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COLUMBIA   UNIVERSITY 
DEPARTMENT     OF     PHYSIOLOGY 
THE    JOHN    G.   CURTIS    LIBR^ 


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WORKS  OF  J.  A.  MANDEL 


PUBLISHED    BY 


JOHN  WILEY  &  SONS. 


A  Tixt=book  of  Physiological  Chemistry. 

By  Olof  Hamtnarslen,  Professor  of  Medical  and 
Physiological  Chemistry  in  the  University  of 
Upsala.  Authorized  translation,  from  the  second 
Swedish  edition  and  from  the  author's  enlarged 
and  revised  German  edition,  by  John  A.  Mandel, 
Assistant  to  the  Chair  of  Chemistry,  etc.,  in  the 
Bellevue  Hospital  Medical  College  and  in  the  Col- 
lege of  the  City  of  New  York.     8vo,  cloth,  $4.00. 

Handbook  for  Bio-Chemical  Laboratory. 

i2mo,  cloth,  $1.50. 


rninnrjrrfKnn 
A  TEXT-BOOK 


OF 


PHYSIOLOGICAL   CHEMISTRY. 


OLOF  HAMMAKSTEN, 

Professor  of  Medicul  (ind  Physiological  Chemistry  in  the 
University  of  Upsala. 


%x\ihoxxit^  Cninshition 

FBOM  THE  AUTHOR'S  ENLARGED  AND  REVISED 
FOURTH  GERMAN  EDITION 


St 

JOHN  A.  MANDEL, 

Professor  of  Chemistry  and  Physics,  and  of  Physiological  Chemistry,  in  tfte 
New  York  University  and  Bellevue  Hospital  Medical  College. 


THIRD    EDITION, 

SECOND   THOUSAND. 


NEW   YORK: 

JOHN  Wn.EY   &   SONS. 
London:    CHAPMAN  &  HALL,   Limited. 

1901. 


Copyright,  1900, 

BY 

JOHN  A.  MANDEL. 


ROBERT  DRUMMOND,   PRINTER,    NEW   YORK. 


PREFACE  TO  THE  SECOND  GERMAN  EDITION. 


After  the  appearance  of  the  first  Swedish  edition  of  this  text-book  I 
"was  asked  by  several  colaborers  abroad  to  provide  a  German  translation, 
which  was  at  that  time  impossible  for  several  reasons.  But  I  found  it  verv 
difficult  to  decline  a  similar  proposal  whicli  I  received  from  many  col- 
leagues after  the  second  edition  appeared. 

I  yielded,  therefore,  to  their  expressed  wishes;  but  I  found  after  a 
time  that  it  was  impossible  to  obtain  a  translator  in  this  special  province 
of  science,  notwithstanding  the  unwearied  exertions  of  my  publisher. 
Nothing  remained  for  me  but  to  undertake  the  translation  myself  ; 
hence  I  ask  the  reader's  indulgence  for  possible  idiomatic  or  literal  errors. 

Specialists  will  at  once  perceive  that  the  book  before  them  is  not  a 
complete  or  detailed  text-book.  My  intention  was  merely  to  supply 
students  and  physicians  with  a  condensed  and  as  far  as  possible  objective 
representation  of  the  principal  results  of  physiologico-cheniical  research  and 
also  with  the  principal  features  of  physiologico-chemical  methods  of  work. 
It  seems  to  me  that  I  have  followed  a  common,  practical,  even  if  not 
strictly  correct  usage  in  allowing  space  in  this  book  to  the  more  important 
pathologico-chemical  facts,  although  I  have  given  the  book  the  title  Text- 
book of  Physiological  Chemistry. 

The  arrangement  of  subject-matter,  which  deviates  considerably  from 
that  generally  followed  in  text-books,  was  caused  by  the  manner  in  whicli 
physiological  chemistry  is  studied  in  Sweden.  Here  physiologico-  and 
pathologico-chemical  laboratory  practice  is  obligatory  on  all  students  of 
medicine.  In  the  arrangement  of  such  practical  work  I  continually  kept 
in  view  that  it  should  not  consist  of  isolated,  purely  chemical  or  analytico- 
chemical  problems,  but  that,  as  far  as  possible,  it  should  always  go  hand  in 
hand  with  tiie  study  of  the  different  chapters  of  chemical  physiology. 

The  study  of  physiologico-chemical  processes  within  the  animal  body 
must  precede  the  study  of  its  component  parts,  its  fluids  and  tissues;  and 
this  latter  study,  according  to  my  experience,  will  then  only  inspire  true 

)ii 


IV  PREFACE  TO   THE  SECOND    GERMAN  EDITION. 

interest  if.  the  study  of  the  physiological  significance  of  those  component 
parts  be  closely  pursued  in  connection  with  that  of  the  transformations  which 
take  place  in  these  fluids  and  tissues. 

In  view  of  this  arrangement  of  subject-matter,  and  in  order  to  render 
my  book  of  greater  interest  and  utility  to  those  who  do  not  wish  to  take 
cognizance  of  its  analytico-chemical  part,  I  have  distinguished  the  latter  by 
different  setting  of  the  type.  With  the  exception  of  urinary  analysis,  which 
practically  is  of  peculiar  importance  and  which  has  been  treated  somewhat 
elaborately,  this  part  in  general  depicts  only  the  main  points  in  the  methods 
of-  preparation  and  of  analytical  methods.  The  instructor  who  su23erintend& 
the  laboratory  practice  and  who  chooses  the  problems  for  work  has  ample 
opportunity  to  give  the  beginner  the  necessary  advanced  directions,  and  for 
the  more  experienced  student,  as  well  as  for  the  specialist,  the  excellent 
works  of  Hoppe-Seyler,  Neubauer-Huppeet,  and  others  render  more 
explicit  directions  superfluous. 

Olof  Hammaesten". 
Upbala,  October,  1890. 


PREFACE   TO  THE  THIRD   GERMAN  EDITION. 


The  present  edition,  which  differs  from  tlie  second  in  the  arrangement 
of  matter,  contains  three  new  chapters.  The  wonderful  development  of 
our  knowledge  of  the  chemistry  of  the  carboliydrates  in  recent  times  has 
made  it  necessary  to  introduce  a  special  chapter  on  this  subject;  and  as 
the  two  chief  groups  of  organic  foods,  the  protein  substances  and  the  carbo- 
hydrates, are  treated  of  in  special  chapters,  the  third  group,  the  fats,  like- 
wise has  a  chapter  devoted  to  it.  It  also  appears  appropriate  to  treat  the 
rather  extensive  subject  of  the  chemistry  of  resjiiration  in  a  special  chapter 
and  not,  as  heretofore,  in  connection  with  tlie  blood.  Another  deviation 
from  the  earlier  editions  is  that  the  present  edition  is  supplied  with  the 
references  to  the  literature,  in  pursuance  of  the  request  made  on  many  sides. 
This  edition  is  also  thoroughly  revised  and  enlarged  according  to  tlie  advance- 
ment of  the  science;  still  it  was  naturally  impossible  to  incorporate  into  the 
text  the  various  papers  ai-)pearing  or  accessible  to  me  during  the  printing  of 
this  edition. 

Olof  Hammarsten. 
Upsala,  April,  1895. 

V 


PREFACE  TO   THE  FOURTH   GERMAN  EDITION. 


As  this  work  is  not  a  complete  handbook,  but  only  a  concise  text-book 
for  students  and  physicians,  I  have  considered  it  very  desirable,  in  tlie 
preparation  of  this  edition,  not  to  enlarge  the  size  of  the  volume.  In  view 
of  the  vast  amount  of  new  material  supplied  during  the  last  four  years,  this 
task  was  a  very  difficult  one,  and  its  accomplishment  was  made  j^ossible  only 
by  excluding  those  theories  which  in  the  light  of  recent  researches  have 
become  obsolete,  and  by  condensing  some  portions  of  the  matter  of  the  pre- 
vious edition.  For  this  purpose  a  thorough  revision  of  some  of  the  chapters 
and  a  complete  rewriting  of  others  were  necessary.  By  means  of  a  new, 
space-saving  arrangement  of  foot-notes  the  number  of  references  to  litera- 
ture has  been  increased.  The  original  plan  of  the  book,  however,  remains 
unchanged. 

Olof  Hammarsten. 

Upsala,  April  17,  1899. 


TRANSLATOR'S  PREFACE  TO  THE  THIRD 
AMERICAN  EDITION 


Eecognizing  the  importance  of  keeping  a  text-book  up  to  date,  and 
especially  one  on  a  subject  which  is  making  such  rapid  advances  as  physi- 
ological chemistry,  I  was  led  to  make  a  translation  of  the  fourth  German 
edition  soon  after  the  second  American  edition  was  issued.  The  aatlior's 
addenda  have  been  incorporated  into  the  text,  bringing  the  available  litera- 
ture up  to  April  1. 

JoHX  A.  Mandel. 

November,  1899. 

Ti 


CONTENTS. 


CHAPTER  I. 

PAGE 

Inthoduction 1 

CHAPTER  II. 
Protein  Substances 15 

CHAPTER  III. 
Carbohydrates 71 

CHAPTER  IV. 
Animal  Fats 92 

CHAPTER  V. 
The  Animaj.  Cell 99 

CHAPTER  VI. 
The  Blood 123 

CHAPTER  VII. 
Chyle,  Lymph,  Transudations  and  Exudations 183 

CHAPTER  VIII. 
The  Liver 206 

CHAPTER  IX. 
Digestion 249 

CHAPTER  X. 
Tissues  of  the  Connective  SuBST.JiNCE 316 

CHAPTER  XL 
Muscle 332 

CHAPTER   XII. 

Brain  and  Nerves 358 

vil 


TLl  CONTENTS. 

CHAPTER  XIII. 

PAGE 

Organs  of  Generation 370 

CHAPTER  XIV. 
Milk 385 

CHAPTER  XV. 
Urine 405 

CHAPTER   XVI. 
The  Skin  and  its  Secretions 521 

CHAPTER   XVII. 
Chemistry  op  Respiration , „.. .  530 

CHAPTER  ::VIII. 
Metabolism 546 


PHYSIOLOGICAL   CHEMISTRY. 


CHAPTER  I. 
INTRODUCTION. 

It  follows  from  the  law  of  the  conservation  of  force  and  matter  that 
living  beings,  plants  and  animals,  can  produce  neither  new  matter  nor  new 
force.  They  are  only  called  upon  to  appropriate  and  assimilate  already 
existing  material  and  to  transform  it  into  new  forms  of  force. 

Out  of  a  few  relatively  simple  combinations,  especially  carbon  dioxide 
and  water,  together  with  ammonium  compounds  or  nitrates,  and  a  few 
mineral  substances,  which  serve  as  its  food,  the  plant  builds  up  the 
extremely  complicated  constituents  of  its  organism,  proteids,  carbohydrates, 
fats,  resins,  organic  acids,  etc.  The  chemical  work  which  is  performed  in 
the  plant  must  therefore,  in  the  majority  of  cases,  consist  in  syntheses;  but 
besides  these,  processes  of  reduction  take  place  to  a  great  extent.  The 
kinetic  energy  of  the  sunlight  induces  the  green  parts  of  the  plant  to  split 
off  oxygen  from  the  carbon  dioxide  and  water,  and  this  reduction  is  generally 
considered  as  the  starting-point  of  the  following  syntheses.  In  the  first 
place  formaldehyde  is  produced,  CO,  +  11, 0  =  CH,0  -f  0, ,  which  then 
by  condensation  is  transformed  into  dextrose,  and  this  then  serves  in  the 
structure  of  other  bodies.  The  kinetic  energy  of  the  sun,  which  produces 
this  splitting,  is  not  lost;  it  is  only  transformed  into  another  form  of  force 
— into  the  potential  energy  or  chemical  tension  of  the  free  oxygen  on  the 
one  side,  and  the  combinations  less  oxygenated,  pioduced  by  the  synthesis, 
on  the  other  side. 

Tliese  conditions  are  not  the  same  in  animals.  They  are  dependent 
either  directly,  as  the  herbivora,  or  indirectly,  as  the  carnivora,  upon  plant- 
life,  from  which  they  derive  the  three  chief  groups  of  organic  nutritive 
matter — proteids,  carbohydrates,  and  fats.  These  bodies,  of  whicli  the 
protein  substances  and  fat  form  the  chief  mass  of  the  animal  body,  undergo 
Avithin  the  animal  organism  a  cleavage  and  oxidation,  and  yield  as  final 


2  INTROD  UCTION. 

prodncts  exactly  the  above-mentioned  chief  components  of  the  nutrition  of 
2)lants,  namely,  carbon  dioxide,  water,  and  ammonia  derivatives,  which  are 
ricli  in  oxygen  and  have  little  energy.  The  chemical  tension,  which  is 
partly  combined  with  the  free  oxygen  and  partly  stored  up  in  the  above- 
mentioned  more  complex  chemical  compounds,  is  transformed  into  living 
force,  heat,  and  mechanical  work.  While  in  the  plant  reduction  processes 
and  syntheses,  which  are  active  in  the  conversion  of  living  force  into 
potential  energy  or  chemical  tension,  are  the  prevailing  forces,  we  find  in 
the  animal  body  the  reverse  of  this,  namely,  cleavage  and  oxidation 
ji recesses,  which  convert  chemical  tension  into  living  force  {vis  viva). 

This  difference  between  animals  and  plants  must  not  be  overrated,  nor 
must  we  consider  that  there  exists  a  sharp  boundary-line  between  the  two. 
This  is  not  the  case.  There  are  not  only  lower  plants,  free  from  chloro- 
phyll, which  in  regard  to  chemical  processes  represent  intermediate  steps 
between  higher  plants  and  animals,  but  the  difference  existing  between  the 
higher  2)lants  and  animals  is  more  of  a  quantitative  than  a  qualitative  kind. 
Plants  require  oxygen  as  peremptorily  as  do  animals.  Like  the  animal,  the 
plant  also,  in  the  dark  and  by  means  of  those  parts  which  are  free  from 
chlorophyll,  takes  up  oxygen  and  eliminates  carbon  dioxide,  while  in  the 
light  the  oxidation  processes  going  on  in  the  green  parts  are  overshadowed 
or  hidden  beneath  the  more  intense  reduction  processes.  Like  the  animal 
the  fermentive  fangi  transform  chemical  tension  into  living  energy  and 
heat;  and  even  in  a  few  of  the  higher  plants — as  the  aroidece  when  bearing 
fruit — a  considerable  development  of  heat  has  been  observed.  The  reverse 
is  found  in  the  animal  organism,  for,  besides  oxidation  and  splitting,  reduc- 
tion processes  and  syntheses  also  take  place.  The  contrast  which  seemingly 
exists  between  animals  and  plants  consists  merely  in  that  in  the  animal 
organism  the  processes  of  oxidation  and  splitting  are  prevalent,  while  in  the 
plant  those  of  reduction  and  synthesis  have  thus  far  been  observed. 

AVoiiler'  in  1824  furnished  the  first  example  of  synthetical 
PROCESSES  within  the  animal  organism.  He  showed  that  when  benzoic  acid 
is  introduced  into  the  stomach  it  reappears  as  hippuric  acid  in  the  urine, 
after  it  combines  with  glycocoll  (amido-acetic  acid).  Since  the  discovery 
of  this  synthesis,  which  may  be  expressed  by  the  following  equation, 

C.H,.C001I  +  NH,.CH,.COOH  =  NH(C.H,.CO).CH,.COOH  +  H,0, 

Benzoic  acid  Glycocoll  Hippuric  acid 

and  which  is  ordinarily  considered  as  a  type  of  an  entire  series  of  syntheses 
occurring  in  the  body  where  water  is  eliminated,  the  number  of  known 
syntheses  in  the  animal  kingdom  has  increased  considerably.  Many  of 
these  syntheses  have  also  been  artificially  produced  outside  of  the  organism, 

'  Berzelius,  Lebrb.  d.  Cbemie,  ilbersetzl  von  Wobler,  Bd.  4,   Dresden,  1831. 


ANIMAL   OXIDATIONS.  S 

and  nnmerons  examples  of  animal  syntheses  of  which  the  course  is  abso- 
lutely clear  will  be  found  in  the  following  pages.  Besides  tliese  well-studied 
syntheses,  there  occur  in  the  animal  body  also  similar  processes  unquestion- 
ably of  the  greatest  importance  to  animal  life,  but  of  which  we  know 
nothing  with  positiveness.  We  enumerate  as  examples  of  this  kind  of 
synthesis  the  reformation  of  the  red-blood  pigment  (the  haemoglobin),  the 
formation  of  the  different  proteids  from  the  peptones,  the  formation  of  fat 
from  carbohydrates,  and  others. 

Formerly  tlie  view  was  generally  accepted  that  animal  oxidatiox  took 
place  in  the  fluids,  while  to-day  we  are  of  the  opinion,  derived  from  the 
investigations  of  Pfluger  and  his  pupils,'  that  it  is  connected  with  the 
form-elements  and  the  tissues.  The  question  how  this  oxidation  in  the 
form-elements  proceeds  and  how  it  is  induced  cannot  be  answered  with, 
certainty. 

When  a  body  is  oxidized  by  neutral  oxygen  at  ordinary  temperature  or 
at  the  temperature  of  the  body,  the  body  is  called  easily  oxidized  or  auto- 
oxidized  and  the  process  is  called  a  direct  oxidation  or  autooxidation.  As 
the  oxygen  of  the  inhaled  air,  as  also  of  the  blood,  is  neutral,  molecular 
oxygen,  the  old  assumption  that  ozone  occurs  in  the  organism  has  now  been 
discarded  for  several  reasons.  On  the  other  hand  the  chief  groups  of 
organic  nutritives,  carbohydrates,  fat,  and  proteids,  the  last  two  forming 
the  chief  mass  of  the  animal  body,  are  not  autooxidizable  substances.  They 
are  on  the  contrary  bradoxidizable  (Traube)  or  dysoxidizable  bodies. 
They  are  nearly  indifferent  to  neutral  oxygen,  and  it  is  therefore  a  question 
how  an  oxidation  of  these  and  other  dysoxidizable  bodies  is  possible  in  the. 
animal  body. 

In  explanation  it  is  very  generally  admitted  that  the  oxygen  is  made 
active  and  this  causes  a  secondary  oxidation.  It  is  generally  conceded  that 
in  autooxidation  a  cleavage  of  neutral  oxygen  takes  place.  The  autooxidiz- 
able substance  splits  the  oxygen  molecule  and  combines  with  one  of  the^ 
oxygen  atoms,  while  the  other  free  atom  as  active  oxygen  may  oxidize  the. 
simultaneously  present  dysoxidizable  substances.  Such  a  subordinate  oxi- 
dation is  called  an  indirect  or  secondary  oxidation.  The  explanation  of 
animal  oxidations  has  been  attempted  by  the  supposition  that  the  oxygen  is 
made  active  and  thus  produces  secondary  oxidation. 

The  cause  of  the  animal  oxidation  is  considered,  by  PflCger  and 
several  other  investigators,  to  be  dependent  upon  the  special  constitution  of 
the  protoplasmic  proteids.  This  investigator  calls  the  proteids  outside  of 
the  organism,  and  also  those  which  circulate  in  the  blood  and  fluids,  "  non- 
living proteids"  as  compared  to  those  which  are  converted  by  the  activity 

'  PflQger,  Pfluger's  Archiv.  Bdd.  6  and  10  ;  Finkler,  ilnd.,  Bdd.  10  and  14  ;  Oertman., 
ibid.,  Bdd.  14  and  15;  Hoppe-Seyler,  i/nd.,  Bd.  7. 


4  INTRODUCTION. 

of  the  living  cell  into  living  protoplasm,  which  he  calls  "  living  proteids'* 
or  a  special  form  of  proteid  called  "  active  proteid  "  by  Loew.  It  is  now 
iilso  considered  that  this  "living  proteid"  differs  from  the  "non-living 
proteid"  by  a  greater  mobility  of  the  atoms  within  the  molecule,  and  it 
may  be  characterized  by  a  greater  inclination  towards  intramolecular 
changes  of  position  of  these  atoms.  The  reason  for  these  greater  intra- 
molecular movements  Pfluger  ascribes  to  the  presence  of  cyanogen, 
LoEW  to  the  presence  of  aldehydic  groups,  and  Latham  '  attributes  it  to 
the  presence  of  a  chain  of  cyanalcohols  in  the  proteid  mloecule. 

Pfluger  considers  these  differences  between  ordinary  proteids  and 
living  protoplasmic  proteids  as  the  cause  for  the  oxidation  processes  in  the 
animal  organism.  These  processes  show  certain  similarity  to  the  oxidation 
of  phosphorus  in  an  atmosphere  containing  oxygen.  In  this  process  the 
phosphorus  is  not  only  itself  oxidized,  but,  as  it  splits  the  oxygen  molecules 
and  sets  free  oxygen  atoms  (active  oxygen),  it  may  cause  at  the  same  time 
an  indirect  or  secondary  oxidizing  action  upon  other  bodies  present.  In  an 
analogous  way  the  living  protoplasmic  proteid,  which  is  not,  like  dead 
protpid,  indifferent  to  molecular  oxygen,  may  cause  a  splitting  of  the 
oxygen  molecule,  thus  becoming  itself  oxidized,  and  at  the  same  time 
setting  oxygen  atoms  free,  which  may  cause  a  secondary  oxidation  of  other 
less  oxidizable  substances. 

According  to  Pfluger  the  oxygen  may  be  made  active  in  this  way. 
Active  oxygen  may  also  be  produced,  according  to  0.  Nasse,  by  a  hydroxy- 
lization  of  the  constituents  of  the  protoplasm  with  the  splitting  off  of  mole- 
cules of  water.  If  benzaldehyde  is  shaken  with  water  and  air  an  oxidation 
of  the  benzaldehyde  into  benzoic  acid  takes  place,  while  oxidizable 
substances  present  at  the  same  time  may  also  be  oxidized.  The  simul- 
taneous presence  of  potassium  iodide  and  starch  or  tincture  of  guaiacnm 
causes  a  blue  coloration  because  the  hydroxyl  (OH)  takes  the  place  of  the 
hydrogen  in  the  aldehyde  group,  and  these  two  hydrogen  atoms,  one  derived 
from  the  aldehyde  and  the  other  from  the  splitting  of  the  water,  have  a 
splitting  action  on  the  molecular  oxygen.  Nasse  and  Eosing  '  have  found 
that  certain  varieties  of  proteid  have  the  property  of  being  hydroxylized  in 
the  presence  of  water,  and  they  include  among  these  proteids  the  substance 
philothion  prepared  by  De  Key-Pailhade  '  from  yeast  and  animal  tissues 

'  PHDger's  Arcbiv,  Bd.  10  ;  Loew  and  Bokorny,  Pflliger's  Arcbiv,  Bd.  25  ;  and  Loew, 
ilnd.,  Bd.  30;  O.  Loew,  The  Energy  of  Living  Protoplasm.  London,  1896  ; — Latham, 
Britisli  Medical  Journal,  1886. 

«  O.  Na«sc,  Rostocker  Zeitung,  No.  .'534,  1891,  and  No.  363,  189")  ;— E.  Rosing,  Unter- 
stichungen  liber  die  Oxydalion  von  Eiweiss  in  Gegenwart  von  Schwefel.  Inaug.  Dis. 
sert.     Rostock,  1891. 

^  De  Rey-Pailhade.  Recberches  exper.  surlePhilotbion,  etc.  Paris,  1891 ; — Nouvelles 
recherches  sur  Ic  Pbilotbion.     Paris,  1892 ;— and  Chem.  Centralhl.,  1897,  Bd,  2,  S.  595. 


ANnTAL   OXIDATIONS.  6 

and  considered  by  him  as  an  oxidation  ferment.  According  to  Nasse  a 
whole  series  of  oxidations  in  the  animal  body  may  be  accounted  for  by  the 
oxygen  atoms  set  free  in  the  hydroxylization  similar  to  that  of  benzalde- 
hyde. 

Another  verywidely  difTnsed  view  exists  in  regard  to  the  origin  of  the 
activity  of  the  oxygen,  namely,  that  by  the  decomposition  processes  in  the 
tissnes  reducing  substances  are  formed  which  split  the  oxygen  molecule, 
uniting  with  one  oxygen  atom  and  setting  the  other  free. 

The  formation  of  reducing  substances  during  fermentation  and  putre- 
faction is  generally  known.  The  butyric  fermentation  of  dextrose  in  which 
hydrogen  is  set  free — C,H,,0,  =  C^II^O,  -[-  2C0,  +  2 (II J — is  an  example 
of  this  kind.  Another  example  is  the  appearance  of  nitrates  in  consequence 
of  an  oxidation  of  nitrogen  in  cases  of  putrefaction,  which  process  is  ordi- 
narily explained  by  the  statement  that,  in  putrefaction,  reducing,  easily 
oxidizable  bodies  are  formed  which  split  oxygen  molecules,  liberating 
oxygen  atoms  which  afterward  oxidize  the  nitrogen.  It  is  assumed,  also 
that  the  cells  of  the  animal  tissues  and  organs  have  the  property  like  these 
lower  organisms,  which  cause  fermentation  and  putrefaction,  of  causing 
splitting  processes  in  which  easily  oxidizable  substances,  perhaps  also 
hydrogen  in  statu  nascendi  (Hoppe-Seyler),  are  produced.  The  observa- 
tions of  Ehrlich,  that  certain  blue  coloring  matters — alizarin  blue  and 
indophenol  blue — are  decolorized  by  the  tissues  of  the  living  animal  and 
become  blue  again  on  exposure  to  air,  seem  also  to  be  a  proof  of  the  occur- 
rence of  easily  oxidizable  combinations  in  the  tissues.  A  further  proof  of 
this  is  found  in  the  observations  of  C.  Ludwig  and  Alex.  Schmidt,'  that 
in  the  blood  of  asphyxiated  animals,  as  well  as  in  the  absence  of  oxygen,  an 
accumulation  of  reducing,  easily  oxidizable  substances  takes  place. 

In  accordance  with  what  has  been  stated  above,  we  may  assume  that  the 
oxidation  in  the  animal  body  takes  place  in  the  following  manner:  The 
forces  peculiar  to  protoplasm,  unknown  to  us,  but  acting  similarly  to  heat 
or  the  enzymes,  cause  a  cleavage,  producing  reducing  and  readily  oxidizable 
products  on  one  side  and  difficultly  oxidizable  products  on  the  other.  The 
first  may  be  directly  oxidized,  causing  also  a  secondary  oxidation  of  dysoxi- 
dizable  bodies.  The  products  formed  by  these  splittings  and  oxidations 
may  perhaps  in  part  be  burned  within  the  body  without  undergoing  further 
cleavage,  but  they  must  probably  first  undergo  a  further  cleavage  and  then 
succumb  to  consecutive  oxidation,  until  after  repeated  cleavage  and  oxida- 
tion the  final  products  of  metabolism  are  formed. 

Nevertheless  there  are  several  investigators  who  do  not  admit  of  the  snp- 

'  Hoppe-Seyler,  Pflllger's  Arcbiv,  Bd.  13  ;  P.  Ehrlich,  Das  Sauerstoffbediivfniss  des 
Organismus.  Berlin,  1885 ; — Alex.  Schmidt,  Arbeiten  aus  der  physiol.  Anstalt  zu 
Leipzig.     1867. 


6  INTRODUCTION. 

position  of  the  oxygen  becoming  active.  According  to  Traube,  in  antooxi- 
dation  we  have  to  deal  in  the  first  place,  not  with  a  cleavage  of  the  oxygen, 
"but  with  a  splitting  of  water  in  which  the  hydroxyl  groups  of  the  water 
combine  with  the  oxidizable  substance,  while  the  hydrogen  atom  set  free  on 
the  decomposition  of  the  water  unites  with  the  neutral  oxygen,  forming 
hydrogen  peroxide,  which  may  naturally  have  an  oxidizing  action.  Accord- 
ing to  the  view  of  Bach,  which  coincides  essentially  with  the  views  of  Eng- 
LER  and  Wild,  oxygen  atoms  are  not  taken  up  in  autooxidation,  but  entire 
oxygen  molecules,  which  by  the  rupture  of  the  double  bonds  of  the  oxygen 

E— 0  yO 

molecule  form  peroxide  combinations  with  the  formula,  |  or  RY    |  . 

E— 0  ^0 

These  can  then,  like  hydrogen  peroxide,  give  up  an  oxygen  atom  to  a  dy- 
■soxidizable  substance,  passing  into  normal  simple  oxides  R^O  or  E"0.  Bach' 
■explains  in  this  way  the  oxidation  process  of  the  animal  body. 

Medyedew  *  has  studied  the  conditions  for  the  oxidation  of  salicylalde- 
hyde  by  tissue  extracts.  He  has  found  on  oxidation  that  two  molecules  of 
the  above  aldehyde  react  with  oxygen  instead  of  one.  His  investigations 
-also/coincide  with  the  views  of  Bach,  Engler,  and  Wild  that  a  peroxide 

C,H,.OH.C(/ 
-combination,  ^   is    produced    as    intermediate    step    in   this 

C.H,.OH.O^ 

^oxidation. 

All  the  views  presented  thus  far  assume  a  continuous  oxidation  of  the 
primary  active  substance.  The  view  has  also  been  suggested  that  animal 
oxidation  may  be  brought  about  by  oxygen-carriers,  i.e.,  by  bodies  which, 
without  being  oxidized  themselves,  act  in  an  analogous  manner  to  the  nitric 
oxide  in  the  manufacture  of  sulphuric  acid  by  alternately  taking  up  and 
introducing  oxygen  in  the  oxidation  of  dysoxidizable  bodies.  Traube  has 
for  a  long  time  explained  the  oxidations  of  the  animal  body  in  this  way,  and 
he  calls  these  questionable  oxygen-carriers  oxidation  ferments.'^ 

It  has  also  been  positively  proven  by  the  researches  of  Jaquet,  Sal- 
KOwsKi,  Spitzer,  Eohmann,  Abklous  and  Biarnes,  Bertrand,  Bou- 
QUELOT,  De  Eey-Pailiiade,  Medvedew,  Pohl,'  and  others,  that  in  the 

'  M.  Traube,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  15,  18,  19,  22,  and  26;  Engler 
and  Wild,  ibid.,  Bd.  30  ;  Bach,  Le  Mouiteur  scientifique,  1897,  and  Compt.  rend..  Tome 
124. 

'  Plliiger's  Arcliiv,  Bd.  74. 

^  M.  Traube,  Theorie  dor  Fermentwirkungeu.     Berlin,  1858. 

*  Jaquet,  Arch.  f.  exp.  Path.  u.  Phurm.,  Bd.  29;  Salkowski,  Centralbl.  f.  d.  med. 
■Wissensch.,  1892  and  1894  ;  Virch()w'.s  Arch.,  Bd.  147  ;  Spitzer,  Pfluger's  Archiv,  Bdd. 
>60  and  67;  Spitzer  and  RObmann,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  28;  Abelous 


ANIMAL   OXIDATIONS.  7 

blood  and  different  tissues  of  the  animal  body,  as  also  in  plant-cells, 
substiuices  occur  wliich  have  the  property  of  causing  certain  oxidations  and 
are  therefore  called  oxidation  ferments  or  oxidases.  The  exact  knowledge 
of  the  nature  of  Jthese  oxidation  ferments  has  been  somewhat  advanced  by 
Spitzer,  who  has  been  able  to  isolate  ferruginous  nucleoproteids  from 
different  animal  organs,  such  as  the  liver,  kidneys,  testicles,  pancreas, 
which  act  as  oxygen-exciters.  These  proteids,  whose  iron  Spitzer  con- 
siders of  special  importance,  readily  decompose  hydrogen  peroxide,  but  they 
may  also  be  detected  in  other  ways,  such  as  by  tiie  formation  of  indophenol 
from  rr-naphthol  and  paraphenyldiamin  in  the  presence  of  alkali.  It  is 
difficult  at  the  present  time  to  judge  of  the  importance  of  the  oxidation 
ferments  wliich  have  been  isolated  from  dead  tissues,  in  the  oxidation 
processes  of  the  living  animal  body.  Further  investigations  as  to  the 
nature  and  action  of  these  bodies  is  very  much  to  be  desired. 

LoEW,'  who  has  opposed  the  view  as  to  the  oxygen  becoming  active  with 
the  setting  free  of  oxygen  atoms,  has  sought  for  the  reason  of  the  oxidations 
in  the  active  proteid  of  the  cells.  The  active  movement  of  the  atoms 
within  the  active  proteid  molecule  is  transmitted  to  the  oxygen  and  to  the 
oxidizable  substance,  and  when  the  dissolution  of  the  molecule  has  proceeded 
to  a  certain  point  the  oxidation  occurs  by  the  chemical  affinity.  This 
oxidation  is  according  to  Loew  a  catalysis,  which  shows  great  analogy  to 
the  oxidation  of  alcohol  under  the  influence  of  platinum-black. 

Schmiedeberg,^  who  also  denies  the  supposition  that  the  oxygen 
becomes  active,  is  of  the  view  that  the  tissue  by  the  mediation  of  the  oxida- 
tions do  not  increase  the  oxidizing  activity  of  the  oxygen,  but  more  probably 
act  on  the  oxidizing  substances,  making  them  more  accessible  to  oxidation. 

The  many  different  views  in  regard  to  the  oxidation  processes  show  us 
strikingly  how  little  positive  is  known  about  these  processes.  The  occur- 
rence of  numerous  intermediary  decomposition  products  in  the  animal  body 
teaches  us  that  the  oxidations  of  the  constituents  of  the  body  are  not  in- 
stantaneous and  sudden,  but  take  place  step  by  step,  and  hand  in  hand  with 
cleavages.  Most  investigators  are  agreed  that  these  decompositions  are 
similar  to  certain  oxidations  studied  by  Drechsel  '  outside  the  animal 
body,  where  oxidations  and  reductions  in  quick  succession  acted  together. 


cl  Biaru6s,  Arch,  de  physiol.  (5),  Tomes  7,  8,  and  9,  and  Compt.  rend.  see.  bid..  Tome 
46  ;  Beitiaud,  Arch,  de  physiol.  (5),  Tomes  8,  9,  and  Coinpt.  rcud.,  Tomes  122,  133,  124  ; 
Bouiquelot,  Compt.  leud.  soc.  biol.,  Tome  48,  and  Compt.  rend.,  Tome  123;  De  Rey- 
Pailhade.  1.  c;  Medvedew,  Pflilger's  Arch.,  Bd.  65;  Pohl,  Arch.  f.  exp.  Path.  u. 
Pharm.,  Bd.  38. 

'  O.  Loew,  The  Energy  of  Living  Protoplasm.     Loudon,  1896. 

»  Arch.  f.  e.\p.  Path.  u.  Pharm.,  Bd.  14. 

•Jour.  f.  prakt.  Chem.  (N.  F.),  Bdd.  22,  29,  38,  and  C.  Liidwig's  Festschrift,  1887. 


8  INTRODUCTION. 

The  views  are  divided  in  regard  to  the  manner  and  origin  of  this  coopera- 
tive action.' 

The  oxidations  in  the  animal  body  have  long  been  designated  as  a 
combustion,  and  snch  a  view  is  easily  reconcilable  with  the  above-mentioned 
views.  In  combustion  in  the  ordinary  sense,  as,  for  example,  the  burning 
of  wood  or  oil,  we  must  not  forget  that  the  substances  themselves  do  not 
combine  with  oxygen.  It  is  only  after  the  action  of  heat  has  decomposed 
these  bodies  to  a  certain  degree  that  the  oxidation  of  the  products  of  such 
decomposition  takes  place  and  is  accompanied  by  the  phenomenon  of  light. 

An  important  source  of  the  living  energy  developed  in  the  body  is  to  be 
sought  for  in  the  oxidation  effected  by  oxygen  of  strong  potential  energy, 
but  CLEAVAGE  PROCESSES  are  also  important.  In  these  complicated  chemi- 
cal compounds  are  reduced  to  simpler  ones,  and  therefore  the  atoms  change 
from  a  labile  equilibrium  to  a  stabler  one  and  stronger  chemical  affinities 
are  satisfied,  converting  chemical  potential  energy  into  living  energy  {vis 
viva).  The  best-known  example  of  such  a  splitting  process  outside  of  the 
animal  organism  is  the  ordinary  alcoholic  fermentation  of  dextrose, 
CjHj.O,  =  2C0,  +  2C,HgO,  in  which  process  heat  is  set  free.  The  animal 
body^inay  also  have  a  source  of  energy  in  the  cleavage  processes  which  are 
not  dependent  on  the  presence  of  free  oxygen.  The  processes  taking  ^^lace 
in  the  living  muscle  yield  an  example  of  this  kind.  A  removed  muscle, 
which  gives  no  oxygen  when  in  a  vacuum,  may,  as  Hermann  °  has  shown, 
work,  at  least  for  a  time,  in  an  atmosphere  devoid  of  oxygen,  and  give  off 
carbon  dioxide  at  the  same  time. 

We  call  cleavage  processes  which  are  accompanied  by  a  decomposition  of 
water  and  then  a  taking  up  of  its  constituents  hydrolytic  cleavages.  These 
cleavages,  which  play  an  important  role  within  the  animal  body,  and  which 
are  most  frequently  met  with  in  the  processes  of  digestion,  are,  for  example, 
the  transformation  of  starch  into  sugar  and  the  splitting  of  neutral  fats 
into  the  corresponding  fatty  acid  and  glycerin : 

C3H,(C,,H3.0J3  +  3H.0  =  C,H,(OH),  +  3(C,,H3eOJ. 

Tristearin  Glycerin  Stearic  acid 

As  a  rule  the  hydrolytic  cleavage  processes  as  they  occur  in  the  animal 
body  may  be  performed  outside  of  it  by  means  of  higher  temperatures  with 
or  without  the  simultaneous  action  of  acids  or  alkalies.  Considering  the 
two  above-mentioned  examples,  we  know  that  starch  is  converted  into 
sugar  when  it  is  boiled  with  dilute  acids,  and  also  that  the  fats  are  split 
into  fatty  acids  and  glycerin  on  heating  them  with  caustic  alkalies  or  by 
the  action  of  superheated  steam.     The  heat  or  the  chemical  reagents  which 

'  See  M.  Nencki,  Arch,  des  sciences  biol.  de  St.  P6toisbonrg,  Tome  1,  p.  483. 
»  TJntersuchungen  liber  den  StofEwechsel  der  Muskeln.     Berlin,  1867. 


FERMENTS  AND  ENZYMES.  9 

are  nsed  for  the  •  performance  of  these  reactions  would  cause  immediate 
death  if  applied  to  the  living  system.  Consequently  the  animal  organism 
must  have  other  means  at  its  disposal  which  act  similarly,  bnt  in  such  a 
manner  that  they  may  work  without  endangering  the  life  or  normal  consti- 
tution of  the  tissues.  Sucli  means  have  been  recognized  in  the  so-called 
%i7iorganize(l  ferme)its  or  enzymes. 

Alcoholic  fermentation,  as  well  as  other  processes  of  fermentation  and 
putrefaction,  is  dependent  upon  the  presence  of  living  organisms,  ferment 
fungi  and  splitting  fungi  of  different  kinds.  The  ordinary  view,  according 
to  the  researches  of  Pasteur,  is  that  these  processes  are  to  be  considered  as 
phases  of  life  of  these  organisms.  The  name  organized  ferments  ov  ferments 
has  been  given  to  such  micro-organisms  of  which  ordinary  yeast  is  an 
example.  However,  the  same  name  has  also  been  given  to  certain  bodies  or 
mixtures  of  bodies  of  unknown  organic  origin  which  are  products  of  the 
chemical  work  within  the  cell,  and  which  after  they  are  removed  from  the 
cell  still  have  their  characteristic  action.  Such  bodies,  for  example  malt 
diastase,  rennin,  and  the  digestive  ferments,  are  capable  in  the  very  smallest 
quantity  of  causing  a  decomposition  or  cleavage  in  very  considerable 
quantities  of  other  substances  without  entering  into  permanent  chemical 
combination  Avitli  the  decomposed  body  or  with  any  of  the  cleavage  or 
decomposition  i)roducts.  These  formless  or  unorganized  ferments  are 
generally  called  enzymes,  according  to  Kuhxe. 

A  ferment  in  a  more  restricted  sense  is  therefore  a  living  being,  while 
an  enzyme  is  a  product  of  chemical  processes  in  the  cell,  a  product  which 
has  an  individuality  even  without  the  cell,  and  which  may  be  active  when 
separated  from  the  cell.  The  splitting  of  invert-sugar  into  carbon  dioxide 
and  alcoliol  by  fermentation  is  a  fermentative  process  closely  connected  with 
the  life  of  the  yeast.  The  inversion  of  cane-sugar  is,  on  the  contrary,  an 
enzymotic  process  caused  by  one  of  the  bodies  or  mixture  of  bodies  formed 
by  the  living  ferment,  which  can  be  severed  from  this  ferment,  and  still 
remains  active  even  after  the  death  of  the  latter.  Consequently  ferments 
and  enzymes  are  capable  of  manifesting  a  different  behavior  towards  certain 
chemical  reagents.  Thus  there  exist  a  number  of  substances,  among  which 
we  may  mention  arsenious  acid,  phenol,  salicylic  acid,  boracic  acid,  sodium 
fluoride,  chloroform,  ether,  and  others,  which  in  certain  concentration  kill 
ferments,  but  which  do  not  noticeably  impair  the  action  of  the  enzymes. 

The  above  view  as  to  the  difference  between  ferments  and  enzymes  has 
lately  been  essentially  shaken  by  the  researches  of  E.  Buciiner."  He  has 
been  able  to  obtain  from  beer-yeast,  by  grinding  and  strong  pressure,  a  cell 
fluid  rich  in  proteid  which  Avhen  introduced  into  a  solution  of  a  fermentable 

'  E.  Buchner,' Ber.  d.  deutscb.  chem.  Qesellsch.,  Bdd.  30  and  31  ;  E.  Buchner  aud 
Rapp.  ibid.,  Bd   81. 


10  INTRODUCTION. 

sugar  caased  a  violent  fermentation.  The  objections'  suggested  from 
several  sides  that  the  fluid  expressed  still  contained  dissolved  living  cell 
substance  has  been  answered  by  several  important  observations  made  by 
E.  and  H.  Buchnee.'  Among  these  observations  we  must  mention  the 
following:  The  active  constituent  of  the  cell  fluid,  zymase,  is  not  influenced 
in  its  action  by  either  chloroform  or  sodium  arsenite  solution  (1^), 
while  these  bodies,  on  the  contrary,  completely  destroy  the  fermentative 
action  of  the  living  yeast-cell.  The  activity  of  the  zymase  is  not  impaired 
by  quantities  of  glycerin,  which  completely  destroy  fermentation  produced 
by  means  of  the  yeast-cell.  According  to  Buchi^er  alcoholic  fermentation 
is  not  directly  connected  with  the  organized  structure  of  the  cell,  but  pro- 
duced by  soluble  products  secreted  by  the  cells,  or  at  least  separated 
therefrom. 

If  the  conclusions  drawn  by  Buchneh  from  these  important  researches 
are  correct,  and  if,  as  is  to  be  expected,  it  can  be  applied  to  other  micro- 
organisms, then  we  can  understand  the  action  of  the  above-mentioned  anti- 
fermentative  and  anti-putrefactive  substances  in  that  they  prevent  the 
production  of  the  active  bodies  by  killing  the  cells  or  crippling  their  func- 
tions.y 

As  the  enzymes  may  act  outside  of  the  cell,  i.e.,  extracellular,  still  this 
does  not  preclude  the  possibility  that  we  may  also  have  enzymes  which 
develop  their  action  within  the  cell  and  are  therefore  intracellular.  As  an 
example  of  such  an  enzyme  we  may  mention  the  enzyme  existing  in  the 
micrococcus  nrese,  which  has  the  power  of  decomposing  urea,  and  also 
another  enzyme,  produced  by  a  bacterium,  which  decomposes  calcium 
formate  into  calcium  carbonate,  carbon  dioxide,  and  hydrogen. 

It  is  doubtful,  indeed  highly  improbable,  whether  it  has  been  possible 
up  to  the  present  time  to  isolate  any  enzyme  in  a  pure  state.  Therefore 
the  nature  of  the  enzymes  and  their  elementary  composition  are  unknown. 
Such  as  have  been  obtained  thus  far  appear  to  be  nitrogenized  and  to  be 
similar  in  some  degree  to  proteid  bodies.  The  enzymes  are  considered  as 
proteid  bodies  by  many  investigators,  but  this  opinion  has  not  sufficient 
foundation.  It  is  indeed  true  that  the  enzymes  isolated  by  certain  investi- 
gators act  like  genuine  proteid  bodies;  but  it  is  undecided  Avhether  or  not 
the  products  isolated  in  these  instances  were  pure  enzymes  or  were  com- 
posed of  enzymes  contaminated  with  proteids. 


'  II.  Buchner,  Silzungsber.  d.  Gesellscli.  f.  Morphol.  u.  Physiol,  in  Miincben,  Bd. 
13,  1897,  Heft  1,  which  also  contains  the  discussiim  on  this  topic.  See  also  Stavenlingtr., 
Ber.  d.  deutsch.  Chem.  Gesellsch.,  Bd.  30. 

'  The  recent  works  on  this  disputed  question  may  be  found  by  referring  to  Abeles, 
Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  31  ;  Buchner  and  liapp,  ibid.,  Bd.  33;  Wro- 
blewski,  Centralbl.  f.  Physiologie,  Bd.  12.  ' 


ENZYMES.  11 

The  enzymes  may  be  extracted  from  the  tissaes  by  means  of  water  or 
glycerin,  especially  by  the  latter,  which  forms  very  stable  solutions  and 
consefjaently  serves  as  a  means  of  extracting  them.  The  enzymes, 
generally  speaking,  do  not  appear  to  be  diffusible.  They  arc  readily  carried 
down  with  other  substances  when  these  precipitate  in  a  finely  divided  state, 
and  this  j^roperty  is  extensively  taken  advantage  of  in  the  preparation  of 
pure  enzymes.'  The  property  of  many  enzymes  of  decomposing  hydrogen 
peroxide  is,  according  to  Alex.  Schmidt,  not  dependent  upon  the  enzyme, 
but  is  caused  by  the  contamination  of  the  enzyme  with  constituents  from 
the  protoplasm.  This  coincides  with  tlie  observations  of  Jacobsen  "  on 
emulsin,  pancreas  enzyme,  and  diastase,  that  the  catalytic  property  may  be 
destroyed  by  proper  means  without  diminishing  the  specific  euzymotic 
action.  The  continued  heating  of  their  solutions  above  +  SO'""  C.  generally 
destroys  most  of  the  enzymes.  In  the  dry  state,  however,  certain  enzymes 
may  be  heated  to  100''  or  indeed  to  150^-160°. C.  without  losing  their 
power.     The  enzymes  are  precipitated  from  their  solutions  by  alcohol. 

We  have  no  characteristic  reactions  for  the  enzymes  in  general,  and  each 
enzyme  is  characterized  by  its  specific  action  and  by  the  conditions  under 
which  it  operates.  But  it  must  be  stated  that,  however  the  different 
enzymes  may  vary  in  action,  they  all  seem  to  have  this  in  common,  that  by 
their  presence  an  impulse  is  given  to  split  more  complicated  combinations 
into  simpler  ones,  whereby  the  atoms  arrange  themselves  from  an  unstable 
equilibrium  into  a  more  stable  one,  chemical  tension  is  transformed  into 
living  force,  and  new  products  are  formed  with  lower  heat  of  combustion 
than  the  original  substance.  The  presence  of  water  seems  to  be  a  necessary 
factor  in  the  perfection  of  such  decompositions,  and  the  chemical  process 
seems  to  consist  in  the  taking  up  of  tlie  elements  of  water. 

The  action  of  the  enzymes  may  be  markedly  influenced  by  external  con- 
ditions. The  reaction  of  the  liquid  is  of  special  importance.  Certain 
enzymes  act  only  in  acid,  others,  and  the  majority,  on  the  contrary,  act  only 
in  neutral  or  alkaline  liquids.  Certain  of  them  act  in  very  faintly  acid  as 
well  as  in  neutral  or  alkaline  solutions,  but  best  at  a  specific  reaction.  The 
temperature  exercises  also  a  very  important  influence.  In  general  the 
activity  of  enzymes  increases  to  a  certain  limit  with  the  temperature.  This 
limit  is  not  always  the  same,  but  depends,  like  the  destructive  action  of 
high  temperatures,  essentially  upon  the  quantity  of  enzyme  and  other  con- 
ditions.'    The  products  of  the  enzymotic  processes   exercise  a   retarding 


'  Brlicke,  Wiener  Sitziingsbericht,  Btl.  43.     1861. 

*  AI.    Schmiill,    Zur   Blutlebre.       Leipzig,    1892 ;— Jucohsen,     Zeitsclir.    f.   pbysiol. 
Chemie,  Bd.  16,  S.  340. 

*  Tammann,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  16,  S.  271  ;  Pugliesie,  Pfliigers  Arch., 
Bd.  69. 


12  INTRODUCTION. 

influence  in  proportion  as  they  accamnlate.     Additions  of  various  kinds 
may  have  a  retarding  and  others  an  accelerating  action.' 

An  enzyme  considered  in  the  proper  sense  is  one  which  has  the  property 
of  producing  hydrolytic  cleavage.  The  three  most  important  groups  of 
these  are  the  amylohjtic  or  diastatic,  the  p'^'oteolytic  or  those  converting 
proteids  into  soluhle  modifications,  and  the  steatolytic  or  fat-splitting 
enzymes.  Inverfin,  which  splits  disaccharides  into  monosaccharides, 
belongs  to  the  true  enzymes,  also  the  tirea-  splitting  and  glucoside-sjjUtting 
enzymes,  Avhich  occur  especially  in  higher  plants.  The  proteid-coagtdating 
enzymes  occupy  a  special  position  amongst  the  enzymes.  The  mode  of 
action  of  these  enzymes,  amongst  which  we  reckon  chymosin  (rennin),  or 
casein-coagulating,  and  fibrin  ferment,  or  blood-coagulating,  is  still  less, 
known  than  the  others.  It  is  rather  generally  admitted  that  we  here  also 
have  to  deal  with  a  hydrolytic  cleavage,  but  still  this  has  not  been  positively 
confirmed. 

We  are  still  in  the  dark  in  regard  to  the  manner  in  which  these  enzymes 
act.  Starting  with  the  assumption  that  when  the  free  ions  are  set  free  by 
the  action  of  enzymes  the  electrical  conductivity  of  the  water  must  be  raised, 
0.  XAsfeE"  experimented  with  soluble  starch,  partly  boiled  and  partly 
unboiled,  and  diastase,  and  determined  the  resistance  according  to  Kohl- 
bausch's  method  and  observed  a  considerable  increase  in  the  conductivity 
of  the  active  diastase  solutions.  The  enzymes  by  their  action  show  in  many 
regards  a  great  similarity  to  so-called  catalytic  or  contact  action,  and  it  is 
the  generally  accepted  view  that  the  enzyme  action  consists  of  a  transfer  of 
movement  to  the  substance  to  be  split. 

As  above  stated,  the  enzymes  are  of  great  importance  for  the  chemical 
processes  going  on  in  the  digestive  tract,  but  we  have  to  add  that  the 
results  of  their  action  are  greatly  complicated  by  processes  of  putrefaction 
which  take  place  in  the  intestine  at  the. same  time,  and  which  are  caused  by 
micro-organisms.  Micro-organisms  therefore  exercise  a  certain  influence  on 
the  physiological  processes  of  the  animal  body.  These  organisms,  when 
they  enter  the  animal  fluids  and  tissues  and  develop  and  increase,  are  of  the 
greatest  pathological  importance,  and  modern  bacteriology  in  relation  to  the 
doctrine  of  infectious  diseases,  founded  by  Pasteur  and  Koch,  gives 
efficient  testimony  to  these  facts. 

Putrefaction  caused  within  the  animal  fluids  and  tissues  by  lower 
organisms  may  produce,  among  others,  combinations  of  a  basic  nature. 
Such  bodies  were  first  found  by  Sei.mi  in  human  cadavers,  and  called  by 
him  cadaver  alkaloids  or  ptomaines.     These  ptomaines,  which  have  been 


'  Fermi  and  Pernossi,  Zeitsclir.  f.  TTygiene,  Bfl.  18.     An  index  of  the  literature  on 
enzymes  may  be  found  v.  in  Moraczewski,  PflUger's  Arch.,  Bd.  69. 
»  Rostocker  Zttr.,  ?894. 


PTOMAINES  AND  LEUCOMAINES.  13 

isolated  from  cadavers  aud  some  from  putrefying  proteid  mixtures,  have 
been  closely  studied  by  Selmi,  Buiegeu,  and  Gautier  '  and  are  cousideied 
as  products  of  chemical  processes  caused  by  putrefaction  microbes.  The 
first  ptomaine  to  be  analyzed  was  coUidin,  CJ[,,N,  obtained  by  Nencki,' 
on  the  putrefaction  of  gelatin  with  pancreas.  Since  then  many  ptomaines 
have  been  analyzed  by  Gautier  and  especially  by  Brieger.  Certain  of 
the  ptomaines  originate  undoubtedly  from  lecithin  and  other  so-called 
extractives  of  the  tissues,  but  the  majority  seem  to  be  derived  from  the 
protein  substances  by  decomposition. 

Some  ptomaines,  although  all  belong  to  tlie  aliphatic  series,  contain 
oxygen,  and  others  are  free  from  oxygen.  The  majority  of  the  true 
ptomaines  belong  to  the  latter  group.  Most  of  the  ptomaines  isolated  by 
Brieger  are  diamines  or  compounds  derived  from  the  same.  Amongst  the 
diamines  we  have  two,  cadaverin,  or  pentamethylendiamin,  0^11, ^N, ,  and 
jnitrescin,  or  tetramethylendiamiu,  C^H,,Xj ,  which  are  of  special  interest 
because  they  have  been  found  in  the  intestinal  tract  and  urine  in  certain 
pathological  conditions,  namely,  cholera  and  cystinuria.'  Some  of  the 
ptomaines  are  exceedingly  poisonous,  while  others  are  not.  The  poisonous 
ones  are  called  toxines,  according  to  the  suggestion  of  Brieger. 

The  formation  of  such  toxines  in  the  decompositions  caused  by  putrefac- 
tive microbes  makes  it  probable  that  the  lower  organisms  acting  in  infectious 
diseases  also  produce  poisonous  substances  which  may  cause  by  their  action 
the  symptoms  or  complications  of  the  disease.  Brieger,  who  has  become 
prominent  by  his  study  of  this  subject,  has  been  able  to  isolate  from 
typhoid  cultures  a  substance  called  fyphotoxin,  which  has  a  poisonous  action 
on  animals;  and  he  has  also  prepared  another  substance,  teiafiin,  from  the 
amputated  arm  of  a  patient  with  tetanus,  animals  inoculated  with  which  die 
exhibiting  symptoms  of  developed  tetanus.* 

As  above  stated,  the  chemical  processes  in  animals  and  plants  do  not 
stand  in  opposition  to  each  other;  they  offer  differences  indeed,  but  still 
they  are  of  the  same  kind  from  a  qualitative  standpoint.  Pfluger  says 
that  there  exists  a  blood-relationship  between  all  living  cells  of  the 
animal  and  vegetable  kingdoms,  and  that  they  originate  from  the  same 
root;  and  if  the  unicellular  plant  organisms  can  decompose  protein  sub- 

'  Selmi,  Sulle  ptomaine  od  alalcoidi  cadaverici  e  loro  importanza  in  tossicologia. 
Bologua,  1878.  Ber.  d.  deutsch.  cliem.  Gesellscb.,  Bd.  11.  Correspond,  by  H.  Schiff  ;— 
Brieger,  Ueber  Ptomaine,  Parts  1,  2,  and  3.  Berlin,  1885-1886  ;— A.  Gautier,  Traite  de 
chimie  appliquce  a  la  physiologic,  Tome  2,  1873.     Compt.  rendus,  Tome  94. 

'  Ueber  die  Zersetzung  der  Gelatine,  etc.     Bern,  1876. 

*  Brieger,  Berlin,  klin.  "Wochenscbr.,  1887;  Baumann  and  Udransky,  Zeitschr.  f. 
physiol.  Chem.,  Bdd.  13  and  15;  Brieger  and  Stadthagen,  Berlin,  klin.  Wochenscbr., 
1889. 

*  Brieger,  Virchow's  Arch.,  Bdd.  112  and  115.  Also  Sitzuugsber.  d.  Berl.  Akad.  d. 
W.,  1889,  and  Berl.  klin.  Wochenscbr.,  1888. 


14  INTRODUCTION. 

stances  in  sach  a  manner  as  to  produce  poisonous  substances,  why  should 
not  the  animal  body,  which  is  only  a  collection  of  cells,  be  able  to  produce 
under  physiological  conditions  similar  poisonous  substances?  It  has  been 
known  for  a  long  time  that  the  animal  body  possesses  this  ability  to  a  great 
extent,  and  as  well-known  evidence  of  this  ability  we  may  mention  various 
nitrogenized  extractives  and  poisonous  constituents  of  the  secretions  of 
certain  animals.  Those  substances  of  basic  nature  which  are  incessantly 
and  regularly  produced  as  products  of  the  decomposition  of  the  protein, 
substances  in  the  living  organism,  and  which  therefore  are  to  be  considered 
as  products  of  the  physiological  exchange  of  material,  have  been  called 
Uucomaines  by  Gautier  '  in  contradistinction  to  the  ptomaines  and  toxines 
produced  by  micro-organisms.  These  bodies,  to  which  belong  several  well- 
known  animal  extractives,  were  isolated  by  Gautier  from  animal  tissues 
such  as  the  muscles.  The  hitherto  known  leucomaines,  of  which  a  few  are 
poisonous  in  small  amounts,  belong  to  the  cholin,  the  uric  acid,  and  the 
creatinin  group. 

The  leucomaines  are  considered  as  being  of  certain  importance  in  caus- 
ing disease.  It  has  been  contended  that  when  these  bodies  accumulate  on 
account  /of  an  incomplete  excretion  or  oxidation  in  the  system,  an  auto- 
intoxication may  be  produced  (Bouchard'  and  others). 

The  toxines  and  the  poisonous  leucomaines  are,  however,  neither  the 
only  nor  the  most  active  poison  produced  by  the  plant  or  animal  cell. 
Later  investigations  have  shown  that  certain  plants  as  well  as  animals  can 
produce  proteids  which  are  exceedingly  poisonous.  Such  poisonous  proteids 
have,  for  example,  been  isolated  from  the  Jequirity  and  castor  beans,  as  also 
from  the  venom  of  snakes,  spiders,  and  other  animals.  The  toxic  proteids 
produced  by  pathogenic  micro-organisms  are  of  special  interest.  Bodies 
have  been  isolated  from  the  cultures  of  various  pathogenic  microbes  which 
are  exceedingly  poisonous  and  which  reproduce  the  symptoms  of  infection 
more  exactly  than  the  toxines.  These  bodies,  whose  proteid  nature  is  still 
questioned,  have  been  called  toxalbumins  by  Brieger  and  Frankel. 

It  is  of  great  interest  that  we  know  also  of  proteid  bodies  such  as  the 
so-called  alexines  in  the  blood-serum,  which  have  a  germicidal  or  bacteri- 
cidal action.  On  the  other  hand  we  also  have  bodies  of  an  alleged  proteid 
nature  which  produce  an  immunity  in  the  animal  body  against  infection 
with  a  certain  microbe  or  protection  against  the  poison  produced  by  the 
same  microbe,  so-called  antitoxins.  The  great  importance  of  these  observa- 
tions is  apparent,  but  as  it  is  not  within  the  range  of  this  book  we  will  not 
farther  discuss  the  subject. 


'  Bull.   soc.   cbim.,  43,  and  A.  Gautier,  Sur  les  alcaloYdes  derives  de  la  destruction 
hacterienne  ou  physiologique  des  tissus  animaux.     Paris,  1886. 

«  Bouchard,  Le9ons  sur  les  auto-iiitoxirations  dans  les  maladies.     Paris,  1887. 


CHAPTER  II. 
THE  PROTEIN  SUBSTANCES. 

The  chief  mass  of  the  organic  constituents  of  animal  tissues  consists  of 
amorphous,  nitrogenized,  very  complex  bodies  of  high  molecular  weight. 
These  bodies,  which  are  either  proteids  in  a  special  sense  or  bodies  nearly 
related  thereto,  take  first  rank  among  the  organic  constituents  of  the  animal 
body  on  account  of  their  great  abundance.  For  this  reason  they  are  classed 
together  in  a  special  group  which  has  received  the  name  j^roteiu  group 
(from  TtpcoTevo,  I  am  the  first,  or  take  the  first  place).  The  bodies 
belonging  to  these  several  groups  are  called  profei7i  sitbstafices,  although  in 
a  few  cases  the  proteid  bodies  in  a  special  sense  are  designated  by  the  same 
name. 

The  seveT'dl  protein  substances  contain  carbon,  hydrogen,  nitrogen,  and 
oxygen.  The  majority  contain  also  sulphur,  a  few  phosphorus,  and  a  few 
also  iro7i.  Copper,  iodine,  and  bromine  have  been  found  in  some  few  cases. 
On  heating  the  protein  substances  they  gradually  decompose,  producing 
inflammable  gases,  ammoniacal  compounds,  carbon  dioxide,  water,  nitrogen- 
ized bases,  as  well  as  many  other  bodies,  and  at  the  same  time  they  emit  a 
strong  odor  of  burnt  horn  or  wool.  On  deep  cleavage  with  acids  they  all 
yield,  beside;  nitrogenous  bases,  abundance  of  monoamido  acids  of  different 
kinds.' 

It  is  at  present  impossible  to  decide  on  a  classification  of  the  protein 
substances  based  upon  their  properties,  reactions,  and  constitution,  as  well 
as  upon  their  solubilities  and  precipitations,  corresponding  to  the  demands 
of  science.  The  best  classification  is  perhaps  the  following  systematic 
summary  of  the  better  known  and  studied  animal  protein  substances,  due 
chiefly  to  Hoppe-Seyler  and  Drechsel." 

'  According  to  the  view  generally  accepted  up  to  the  present  time  only  those  sub- 
stances are  called  true  proteins  which  also  yielded  monoaraido  acids  on  cleavage.  The 
protamins  will   therefore  bo  discussed  as  an  appendix  to  the  protein  substances. 

*  See  "Eiweisskorper."  Ladenbnrg's  HandwOrterbuch  derChemie.  Bd.  3,  S.  534-589, 
which  gives  a  very  complete  summary  of  the  literature  of  protein  substances  up  to  1885. 

15 


16 


TEE  PROTEIN  SUBSTANCES. 


Albumins . 


Globulins. 


I.  Simple  Froteids  or  Albuminous  Bodies. 

(  Seralbumin, 

Ovalbumin, 

Ladalbumin. 

Fibrinogen^ 

Myosin, 

Musculin, 
.  Crystallin. 
j  Casein, 

\  Ovovitellin  (^),  and  others, 
j  Acid  albuminate, 
\  Alkali  albuminate. 
Albumoses  (and  Peptones). 

j  Fibrin, 

\  Proteids  coagulated  by  beat,  and  others. 


Nucleo-albumins . 


Albuminates 


Coagulated  Proteids . 


Haemoglobins. 
Glycoproteids 


Ifucleoproteids. 


II.  Compound  Proteids. 


Mucins  and  Mucinoids 

Hyalogetis, 

Amyloid, 

Ichthulin,  and  others. 

Helicoproteid. 
j  Nucleohiston, 
\  Cytoglobin,  and  others. 


III.  Albumoids  or  Albuminoids. 

Keratin. 

Elastin. 

Collagen. 

Reticulin. 

(Fibroin,  Sericin,  Cornein,  Spongin,  Conchiolin,  BysBus,  and  others.') 

To  this  summary  must  be  added  that  we  often  find  in  the  investigations 
of  animal  fluids  and  tissues  protein  substances  which  do  not  coincide  with 
the  above  scheme,  or  do  so  only  with  difficulty.  At  the  same  time  it  must 
be  remarked  that  bodies  will  be  found  which  seem  to  rank  between  the 
different  groups,  hence  it  is  very  difficult  to  sharply  divide  these  groups. 

'  Tlie  classification  of  the  proteins  is  a  very  difficult  task,  and  no  one  has  up  to  the 
present  Mine  been  able  to  suggest  such  a  classification  free  from  exceptions.  Under  these 
circumstances,  and  as  it  appears  desirable  not  to  enlarge  upon  the  existing  uncertainty  of 
the  nomenclature  in  use,  the  author  considers  it  unnecessary  to  change  the  aljove  sum- 
mary. In  regard  to  other  classifications,  see  Ncumeister,  Lchrbuch  dor  pliysiol.  Chem., 
2.  Aufl.,  1897,  and  Wroblewski,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  30. 


SIMPLE  P  HOT  EI D  8.  17 

I,  Simple  Proteids  c»r  Albuiiiiiious  Bodies. 

The  simple  proteids  are  never-failing  constituents  of  the  animal  and 
vegetable  organisms.  They  are  especially  fonnd  in  the  animal  body,  where 
they  form  the  solid  constituents  of  the  muscles,  glands,  and  the  blood- 
serum,  and  they  are  so  generally  distributed  that  there  are  only  a  few 
animal  secretions  and  excretions,  sncli  as  the  tears,  perspiration,  and  perhaps 
urine,  in  which  they  are  entirely  absent  or  only  occur  as  traces. 

All  albuminous  bodies  contain  carbon^  hydrogen,  nitrogen,  oxygen,  and 
sulphur  ;  '  a  few  contain  a\so  phosphorus.  Iron  is  generally  found  in  traces 
in  their  ash,  and  it  seems  to  be  a  regular  constituent  of  a  certain  group  of 
the  albuminous  bodies,  namely,  the  nucleo-albumins.  The  composition  of 
the  different  albuminous  bodies  varies  a  little,  but  the  variations  are  within 
relatively  close  limits.  For  the  better  studied  animal  proteids  the  following 
composition  of  the  ash-free  substance  has  been  given: 

C 50.  G    —  54. 5  per  cent. 

n G. 5    —    7.3 

N 15.0   —17.6 

S 0.3    —    2.2 

P 0.42—   0.85      " 

0 21.50  —  23.50      '' 

A  part  of  the  nitrogen  of  the  proteid  molecule  is  easily  split  off  as 
ammonia  by  the  action  of  alkalies  (Nasse).  By  the  action  of  nitrous  acid 
on  protein  substances  only  a  very  small  part,  1-2  p.m.,  of  the  nitrogen 
is  expelled,  showing  that  only  a  small  part  thereof  exists  as  amido  groups  in 
the  protein  molecule.'  Hausmaxn  '  has  conducted  investigations  to  show 
the  distribution  of  the  nitrogen  in  the  proteid  molecule.  After  boiling  with 
hydrochloric  acid  he  determined  the  amid  nitrogen  determinable  as  ammonia 
(a),  then  the  nitrogen  of  the  diamido  bodies  precipitable  by  phospho- 
tungstic  acid  {b),  and  the  non-precipi table  nitrogen  of  the  monamido  acids. 
He  found  the  following  percentages  of  the  total  nitrogen: 

a  b  c 

In  crystallized  ovalbumin ...  .      8.53  21.33  67.80 

"  seralbumin 8.90  24.95  68.28 

"casein 13.37  11.71  75.98 

''gelatin 1.61  35.83  62.56 

■  An  exception  is  found  in  the  mycoprotein  of  putrefaction  bacteria  and  the  anthrax- 
proteiu  of  the  anthrax  bacillus,  which  are  sulphur-free  proteids.  See  Nencki  and 
Schaffer,  Journ.  f.  prakt.  Chem.,  Bd.  20  (N.  F.),  and  Nencki,  Ber.  d.  deutsch.  chem. 
Gesellsch.,  Bd.  17. 

"  See  Niisse.  PtiQger's  Arch.,  Bd.  6  ;  Paal,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  29; 
Schiff,  ibid.,  S.  1354,  and  O.  Loew,  Chemiker  Zeit.,  1896. 

» Zeitschr.  f.  physiol.  Chem.,  Bd.  27. 


18  THE  PROTEIN  SUBSTANCES. 

He  found  approximately  1-2^  amid  nitrogen  in  true  proteids,  which 
is  in  accordance  with  the  results  of  other  investigators.  A  part  of 
the  sulphur  separates  as  potassium  or  sodium  sulphide  on  boiling  with 
caustic  potash  or  soda,  and  may  be  detected  by  lead  acetate  (Fleitmaxn, 
Danilewsky,  Krugek,  Fr.  Schulz  ').  What  remains  can  only  be 
detected  after  fusing  with  nitre  and  sodium  carbonate  and  testing  for 
sulphates.  The  relationship  between  the  sulphur  split  off  by  alkali  to  that 
not  split  off  is  different  in  various  proteids.  In  most  proteids  thus  far 
investigated  the  quantity  of  sulphur  which  can  be  split  off  amounts  to  a 
little  less  than  one  half  of  the  total  sulphur  (Schulz).  The  profceid 
molecule  therefore  contains  at  least  2  atoms  of  sulphur.  The  molecular 
weight  of  the  proteids  is  hard  to  determine  accurately,  and  the  results  given 
for  the  same  proteid,  by  various  investigators,  are  often  contradictory. 
The  molecular  weight  is  generally  very  high.  For  the  alkali  albuminate, 
in  whose  formation  from  native  proteid  a  part  of  the  nitrogen  and  sulphur 
is  split  off,  LiEBERKUHX  has  given  the  formula  0,^11,^3^^3802,.  In  regard 
to  the  elementary  formulse  of  proteids  see  Schmiedeberg.* 

The  constitution  of  the  proteid  bodies,  notwithstanding  numerous 
investigations,  is  still  unknown.  By  heating  proteids  with  barium  hydrate 
and  -v^^ter  in  sealed  tubes  at  l50°-200°  C.  for  several  days,  ScHUTZEisr- 
berger  ^  obtained  a  number  of  products  among  which  were  ammonia, 
carbon  dioxide,  oxalic  acid,  acetic  acid,  and,  as  chief  product,  a  mixture  of 
amido-acids.  This  mixture  contained,  besides  a  little  tyrosin  and  a  few 
other  bodies,  chiefly  acids  of  the  series  C^H^n+iNO^  (leucines)  and 
CJI^n-iNO,  {leuceines).  The  leucines  and  leuceines  are  formed  from  more 
complicated  substances,  with  the  general  formula  O^H^^^N^O^ ,  by  hydrolytic 
splitting.  These  substances  are  called  glucojjroteins  by  Schutzenberger 
on  account  of  their  sweet  taste.  The  sulphur  of  the  proteids  yields 
sulphites.  The  three  bodies,  carbon  dioxide,  oxalic  acid,  and  ammonia, 
are  formed  in  the  same  relative  proportion  as  in  the  decomposition  of  urea 
and  oxamid;  therefore  Schutzbnberger  suggests  that  perhaps  proteid 
may  be  considered  as  a  very  complex  ureid  or  oxamid.  Such  a  conclusion 
cannot  be  derived  from  the  above  decomposition  processes  for  several 
reasons. 

On  fusing  proteids  with  caustic  alkali,  amn.onia,  methyl-mercaptan, 
and  other  volatile  products  are  generated;  also  leucin,  from  which  then 
volatile  fatty  acids,  such  as  acetic  acid,  valerianic  acid,  and  also  butyric 

'  Fleitmann,  Annal.  der  Chem.  und  Pharm..  Bd.  66  ;  Danilewsky,  Zeitschr.  f.  pby- 
siol.  Chem.,  Bd.  7  ;  KrDgcr,  PHiiger's  Archiv,  Bd.  43  ;  F.  Schulz,  Zeitsclir.  f,  physioL 
Chem.,  Bd.  25.  See  also  Suter,  ibid.,  Bd.  20,  and  Drechsel,  Centralbl.  f.  Physiol.,  Bd. 
10,  S.  529,  in  regard  to  forms  of  binding  of  the  sulphur. 

»  Arch.  f.  cxp.  Patli.  u.  Pharm.,  Bd.  39. 

'  Annal.  do  Cliim.  el  Phys.  (5),  16,  and  Bull.  soc.  chira.,  23  and  34. 


CLEAVAGE  PRODUCTS  OF  I'liOTEIDS.  19 

acid,  are  formed;  and  tyrosin,  from  which  hiter  phenol,  indol,  and  skatol 
are  produced.  On  boiling  with  mineral  acids  (or  still  better  by  boiling 
with  hydrocliloric  acid  and  tin  chloride,  IIlasiwetz  and  TIahkkmaxn  '), 
the  proteids  yield  amido-acids,  such  as  leucin,  aspartic  acid,  glutamic  acid, 
and  tyrosin  (and  from  vegetable  albumin  ScnuLzE  and  Barbieri  "  obtained 
«-phenylamidopropionic  acid),  also  sulphuretted  hydrogen,  ethyl  sulphide 
(Dkkchskl '),  lencinimid,*  ammonia,  and  nitrogenous  bases  (Dreciisel). 

Amongst  tlie  bases  obtained  by  Drechsel  '  from  casein,  and  by  his 
pupils  E.  FisciiKK,  ^I.  Sik(JFriei),  and  S.  IIedin  from  other  proteids  and 
gelatin  on  boiling  with  hydrochloric  acid  and  tin  chloride,  we  have  one 
having  the  formula  0,11, ,N,0,  or  C,n,,N,0  +  11,0,  which  seems  to  be 
homologous  to  creatin  or  creatinin  and  called  lysatin  or  lysatini7i  by 
Drechsel.  Another  substance,  called  lijsin^  has  the  formula  C,lI,^X,Oj. 
From  its  formula  we  find  that  it  is  homologous  with  ornithin,  CjH,,X,0, 
(Jaffe),  which  it  resembles  in  certain  respects  (see  Appendix  to  this 
Chapter). 

Besides  these  above-mentioned  bases  Hedin  has  obtained  as  cleavage 
products  of  different  protein  substances  the  bases  arginin^  0,11,^X^0, ,  first 
isolated  by  Schulze  and  Steiger  from  etiolated  lupin  and  pumpkin  seeds 
and  also  histidin,  C.HgNjOj ,  prepared  by  Kossel  from  protamins^ 
Drechsel  has  also  found  diamido-acetic  acid  among  the  cleavage  products 
of  casein.  On  boiling  with  baryta-water  both  lysatinin  and  arginin  yield 
urea  among  the  other  cleavage  products,  and  it  is  therefore  possible  ta 
prepare  urea  from  proteid  by  hydrolysis,  without  oxidation,  making  use  of 
these  bases  as  intermediary  steps. 

On  the  cleavage  of  the  proteid,  globin,  contained  in  the  hfemoglobin 
molecule,  wMtli  hydrochloric  acid,  Proscher'  was  able  to  regain  about  one 
half  of  the  carbon,  about  one  half  of  the  nitrogen,  two  thirds  of  the 
hydrogen,  and  a  little  more  than  one  half  of  the  oxygen  as  tangible  cleavage 
products.  On  the  other  hand  R.  Cohx  '  has  been  successful  in  gaining  about 
97.8<i^  of  the  proteid  (casein)  as  crystallizable  or  tangible  cleavage  jjroducts 
in  his  investigations  on  the  quantitative  proteid  cleavage  with  hydrochloric 


'  Annal.  d.  Chem.  u.  Pharm.,  Bdd.  159  aud  169. 

*  Ber.  d.  deutscb.  chem.  Gesellsch.,  Ed.  16. 
»  Central bl.  f.  Physiol..  Bd.  10. 

*  See  Ritthausen,  Ber  d.  deutscb.  chem.  Gesellsch.,  Bd.  29,  and  R.  Cobu,  Zeitschr. 
f.  pbysiol.  Chem.,  Bd.  22. 

'  Sitzuugsber.  d.  math.-pbys.  Klasse  d.  k.  saclis.  Gesellsch.  d.  Wissenschaften,  1889. 
In  the  memoir  "  Der  Abbau  der  Eiweissstoffe,"  Du  Bois-Reymond's  Arch.,  1891, 
Drechsel  gives  a  good  review  of  his  own  investigations  and  of  those  of  bis  pupils. 
Fischer,  Siegfried,  aud  Hedin.  The  literature  of  the  above-meutioued  bases  will  be 
given  in  the  Appendix  to  this  Chapter. 

*  Zeitschr.  f.  phj'siol.  Chem.,  Bd.  27. 
'  Ibid.,  Bd.  26. 


20  THE  PROTEIN  SUBSTANCES. 

acid.  He  approximately  calculated  the  leucin  as  -40-50,^  and  the  glutamic 
acid  30^.  He  obtained  strikingly  small  quantities  of  basic  products.  He 
also  found  CO,  and  oxalic  acid  among  the  cleavage  products  of  proteids 
with  acid. 

Proteids  are  decomposed  by  the  action  of  proteolytic  enzymes  in  the 
presence  of  water.  First  proteid  bodies  of  lower  molecular  weight  are 
formed — albumoses  and  peptones — and  then  on  further  decomposition 
amido-acids  such  as  leucin,  tyrosin,  and  aspartic  acid.  Both  lysin, 
lysatinin,  arginin,  and  histidin  may  be  produced  on  far-reaching  decomposi- 
tion (in  tryptic  digestion).  On  the  extensive  decomposition  a  chromogen 
may  also  be  formed,  which  gives  a  violet  color  with  chlorine-  or  bromine- 
water.  This  chromogen,  which  is  formed  in  all  far-reaching  decompositions 
of  proteids  where  leucin  and  tyrosin  are  formed,  is  called  proteinocliromogen 
by  Stadelmann,  and  trypto2}lian  by  Neumeister.  Nencki  '  considers  this 
chromogen  as  the  mother-substance  of  various  animal  pigments. 

A  great  many  substances  are  produced  in  the  putrefaction  of  proteids. 
Pirst  the  same  bodies  as  are  formed  in  the  decomposition  by  means  of 
proteolytic  enzymes  are  produced,  and  then  a  further  decomposition  occurs 
with  the  formation  of  a  large  number  of  bodies  belonging  to  both  the 
alipljatic  and  aromatic  series.  Belonging  to  the  first  series  we  have 
ammonium  salts  of  volatile  fatty  acids,  such  as  caproic,  valerianic,  and 
butyric  acids,  also  succinic  acid,  carbon  dioxide,  methane,  hydrogen, 
sulphuretted  hydrogen,  methyl-mercaptan,  and  others.  The  ptomaines  also 
belong  to  these  products  and  are  probably  formed  by  very  different  chemical 
processes  or  even  syntheses. 

E.  Salkowski  divides  the  putrefactive  products  of  the  aromatic  series, 
into  three  groups:  (a)  the  phenol  group,  to  which  tyrosin,  the  aromatic 
oxy -acids,  phenol,  and  cresol  belong;  {l)  the  phenyl  group,  including 
phenylacetic  acid  and  phenylpropionic  acid;  and  lastly  (c)  the  indol  group, 
which  includes  indol,  skatol,  and  skatolcarbonic  acid.  These  various 
aromatic  products  are  formed  during  the  putrefaction  with  access  of  air. 
Nencki  and  Bovet'  obtained  only  p.-oxyphenylpropionic  acid,  phenyl- 
propionic  acid,  and  skatolacetic  acid  on  the  putrefaction  of  proteids  by 
anaerobic  schizomycetes  in  the  absence  of  oxygen.  These  three  acids  are 
produced  by  the  action  of  nascent  hydrogen  on  the  corresponding  amido- 
acid,  namely,  tyrosin,  jDhenylamidopropionic  acid,  and  skatolamidoacetic 
acid,  and  these  three  last-mentioned  amido-acids  exist,  according  to 
Nencki,  preformed  in  the  proteid  molecule. 

'  Stadelmann,  Zeitscbr.  f.  Biologic,  Bd.  26;  Neumeister,  ibid.,  Bd.  26,  S.  329  ; 
Nciicki,  Schweizer.  Wocbenscbr.  f.  Pliarnmcie,  1891,  and  Ber.  d.  deutscli.  chem.  Ge- 
sellsch.,  Bd.  28. 

*  Salkowski,  Zeit.schr.  f.  pbysiol.  Cbeui.,  Bd.  12,  S.  215  ;  Nencki  uiid  Bovel,  Monats- 
beft.  f.  Cbem..  Bd.  10. 


DECOMPOSITION  rno DUCTS   OF  I'liOTKIDS.  21 

On  distillation  with  snlphuric  acid  the  2)roteids  yield  a  little  fnrfurol, 
which  indicates  the  presence  of  a  carbohydrate  group  in  the  proteid  mole- 
cule. According  to  Pavy  even  a  carbohydrate,  which  he  considers  as 
animal  gum,  can  be  split  oil  from  ovalbumin,  and  from  this  a  reducing  sub- 
stance is  formed  on  boiling  with  an  acid.  This  so-called  carbohydrate  is, 
according  toWEYDEMAXX,  certainly  a  nitrogenous  substance,  but  Pavy  has 
succeeded  in  obtaining  the  reducing  substance  directly  from  ovalbumin  by- 
boiling  with  acid,  and  has  prepared  an  osazon  therefrom.  This  osazon, 
whose  melting-point  is  182°-185°,  has  been  prepared  by  Krawkow  '  from 
certain  other  proteids,  and  he  therefore  concludes  that  the  carbohydrate 
group  of  the  various  proteids  is  the  same.  Tlie  fact  that  a  reducing  carbo- 
hydrate can  be  split  off  from  certain  proteids,  although  small  in  amount, 
has  been  positively  confirmed.  Tiie  splitting  off  of  a  carbohydrate  is  not 
possible  from  several  pure  proteids,  such  as  casein,  vitellin,  myosin,  and 
fibrinogen.  Up  to  the  present  time  it  has  been  possible  only  when  impure 
proteids,  such  as  fibrin,  or  mixtures  of  various  protein  substances,  such  as 
lactalbumin,  ovalbumin,  or  seralbumin  were  used.  As  example  we  may  state 
that  Spexzer,  as  well  as  K.  Morxer,  was  unable  to  prepare  a  reducing 
carbohydrate  from  specially  purified  ovalbumin,  while  other  investigators 
claim  to  have  obtained  said  substance.  This  circumstance  can  perhaps  be 
explained  by  the  fact  that  the  egg-albumin  is  a  mixture  of  several  sub- 
stances, among  which  is  a  glycoproteid,  which  has  been  prepared  in  a  crystal- 
line state  from  ovalbumin  by  Hofmeister.''  The  important  question 
whether  a  carbohydrate  group  can  be  split  off  from  pure  proteids  not 
contaminated  with  glycoproteids  requires  further  proof. 

EicHiioi.z  '  has  prepared  an  osazon  from  ovalbumin,  which  has  a  melting- 
point  of  202°-20G°,  while  he  was  unable  to  prepare  an  osazon  from  either 
casein  or  seralbumin.  Osazons  have  been  prepared  by  Blumexthal  and 
Meyer*  from  ovalbumin  and  also  from  the  proteid  of  the  yolk  by  boiling 
with  acids.  The  osazon  from  the  yolk  had  a  melting-point  of  203°  and  waa 
l»vo-rotatory,  Avhile  that  from  ovalbumin  melted  at  200°-205°  and  showed 
no  positive  hevo-rotatory  power.  These  investigators  do  not  consider  the 
carbohydrate  split  off  as  an  integral  constituent  of  the  proteid  molecule. 
They  rather  consider  the  proteids  yielding  carbohydrates  as  glycoproteids, 
and  this  view  is  also  accepted  by  Eichholz.     J.  See.maxn  '"  obtained  9f^ 

'  Puvy,  Tbe  Pliysiolojry  of  the  Carbohydrates.  London,  1894 ; — Weydemaun, 
"Ueber  den  sog.  thierisclie  Ganimi,"  etc.  Inaug.-Dissert.  Marburg,  1896  ;— Kraw- 
kow, Pfliiger's  Arch.,  Bd.  65. 

''  SiKnizer,  Zeitschr.  f.  phj'siol.  Cheni.,  Bd.  24  :  Morner,  Centralbl.  f.  Phj'siol.,  Bd.  7; 
Hofmeister,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  24,  S.  169. 

'  Journal  of  Physiol.,  Vol.  23. 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  32. 

*  Bons'  .\.rch.  f.  Verdaiiuntrskraiikheiteu.  Bd.  4. 


22  TEE  PROTEIN  SUBSTANCES. 

redncing  sabstance,  calculated  as  dextrose,  from  ovalbumin.  According  to 
^Juller's  method  he  was  able  to  prepare  the  h3^drochloric  acid  coni- 
iDination  of  this  substance  in  question.  From  this  behavior  he  draws  the 
conclusion  that  carbohydrates  split  off  by  the  action  of  acid  are  identical 
with  the  nitrogenous  carbohydrate  derivative  glucosamine,  obtained  by  him 
from  ovomucoid,  and  by  Muller  from  mucin. 

On  boiling  with  barium  hydrate,  or  also  in  pepsin  digestion,  Fraxkel  ' 
lias  split  off  a  nitrogenous  substance  from  purified  ovalbumin  which  gave 
neither  a  reaction  witli  Millox's  reagent  nor  the  Biuret  reaction.  It  is 
readily  soluble  in  water  and  dextro-rotatory.  It  does  not  directly  reduce 
copper  or  bismuth  salts,  but  does  strongly  reduce  them  on  previously  boiling 
with  acid.  The  elementary  analysis  indicates  the  formula  ^2(CgH30^.XII,) 
-p  H  0,  where  n  is  generally  represented  by  2.  Frai5"KEL  considers  it  as  a 
derivative  of  a  biose  and  calls  it  "a/Zfamm"  provisionally.  He  considers 
a  chitosamin,  which  stands  in  close  relationship  to  the  osamin  jirepared  by 
Ml'LLER  and  Seemais:^'  from  mucin  and  ovomucoid,  as  the  basis  of  this 
body. 

In , marked  contrast  to  all  of  these  observations  we  have  the  communica- 
tion/of  0.  Weiss.''  According  to  Pavt's  alkali  method  he  obtained  a 
substance  containing  1.8^  nitrogen,  which  yielded  a  reducing  substance 
after  boiling  with  acid.  This  reducing  substance  gave  an  osazon  having  a 
melting-point  of  179°-191°.  According  to  Weiss  it  is  crystallizable  methyl 
pentose  with  a  melting-point  of  91°-93°  and  isomeric  with  rhamnose. 

B}^  the  oxidaliou  of  proteids  in  acid  solutions,  volatile  fattj""  acids,  their  aldehydes, 
iiitriles,  ketones,  as  well  as  benzoic  acid  are  obtained,  also  hydrocyanic  acid  by  oxidizing 
with  potassium  dichromate  and  acid.  Nitric  acid  gives  various  nitro-products,  such  as 
xanthoproteic  acid  (van  dek  Pants),  triuitroalbumiu  (Loew)  or  oxynilrualbumin, 
nilroben/.oic  acid,  and  otliers.  With  aqua  regia  funiaric  acid,  oxalic  acid,  chlorazol,  and 
other  bodies  are  produced.  By  the  action  of  bromine  under  strong  pressure  a  large 
number  of  derivatives  are  obtained,  such  as  bromanil  and  tribromacetic  acid,  bromo- 
forni,  leucin.  leuciiiimid,  oxalic  acid,  tribromamido-benzoic  acid,  peptone,  and  bodies 
similar  to  humus. 

Bytiiedry  distillation  of  proleids  we  obtain  a  large  number  of  decompo.sition  products 
'of  a  disagreeable  burnt  odor,  and  a  porous  glistening  mass  of  carbon  containing  nitrogen 
ds  left  as  a  re-idue.  The  products  of  distillation  are  partly  an  alkaline  liquid  which  con- 
tains ammonium  carbonate  and  acetate,  ammonium  sulphide,  ammonium  cyanide,  an 
infliimmable  oil  and  other  bodies,  and  a  brown  oil  which  contains  hydrocarbons,  nitro- 
gen ized  bases  belonging  to  the  aniline  and  pyridine  series,  and  a  number  of  unknown 
substances. 

It  is  impossible  here  to  discuss  all  the  products  obtained  by  the  action 
of  different  reagents  on  the  proteids,  but  from  the  above-described  decom- 
position products  from  proteids  it  is  clear  that  the  products  belong  in  part 
to  the  fatty  and  in  part  to  the  aromatic  series.  Observers  are  not  decided 
whether  one  or  more  aromatic  groups  exist  preformed  in  the  proteid  mole- 
cule.    According  to  Nencki  the  proteids  contain  three  aromatic  groups  as 


•  Wien.  Sitzungsber.  Math.-naturw.  Klasse,  Bd.  107,  Abth.  II  b. 

*  Central!)],  f.  Physiol.,  Bd.  12. 


OXIDATION  OF  PliOTEIDS.  23 

mentioned  above:  the  tyrosin  (oxyphenylamidopropionic  acid),  the  phenyl- 
amidopropionic  acid,  and  the  skatolamidoacetic  acid.  Maly,'  on  account 
of  the  oxyprotosnlphonic  acid  prepared  hy  him,  considers  it  not  necessary 
to  recognize  more  than  one  aromatic  group  in  the  jjroteid  molecule. 

By  the  oxidation  of  proteid  by  means  of  potassium  permanganate,  Maly 
obtained  an  acid,  oxyprotosnlplionic  acid,  C  51.^1;  H  0.89;  N  14. .50; 
S  1.77;  0  "^5.54,  which  is  not  a  cleavage  product  but  an  oxidation  product 
in  which  the  group  HII  is  changed  into  SO,. Oil.  This  acid  does  not  give 
the  proper  color  reaction  with  Millox's  reagent  caused  by  aromatic 
hydroxyl  derivatives  (see  below),  nor  does  it  yield  the  ordinary  aromatic 
splitting  products  of  the  proteids.  Still  the  aromatic  group  is  not  absent, 
but  it  seems  to  be  in  another  binding  from  that  in  ordinary  proteid.  On 
oxidizing  with  potassium  dichromate  and  acid  this  group  a2)pears  as  benzoic 
acid,  and  on  fusing  with  alkali  benzol  is  given  off. 

On  continuous  oxidation  a  new  amorphous  acid,  peroxyproteic  acid — 
C  4G.:i2;  H  (i.4;3;  N  l->.:30;  S  0.90;  0  34.09,1^— is  produced  from  the  oxy- 
protosnlphonic acid.  The  peroxyproteic  acid  gives  the  Buiret  reaction,  but 
is  not  precipitated  by  most  of  the  reagents  precipitating  proteids. 

According  to  Berxer'^  in  the  formation  of  oxyprotosulphonic  acid  not 
only  does  an  oxidation  take  place,  but  also  at  tiie  same  time  a  deep  cleavage 
due  to  the  presence  of  alkali.  He  was  able  to  show  the  presence  of  albu- 
moses  and  peptones  as  side  products.  These  differed  from  the  correspond- 
ing products  produced  in  digestion  by  not  yielding  any  indol  or  skatol  on 
fusing  with  potash,  by  not  giving  ]\riLLOX's  reaction,  and  not  containing 
sulphur  blackening  lead.  lie  also  found  acetic  acid,  propionic  acid,  and 
butyric  acid,  and  the  presence  of  valerianic  acid  and  basic  bodies  (lysin, 
histidiu)  was  shown  among  the  cleavage  products.  On  the  cleavage  of 
peroxyproteic  acid  with  baryta  he  found  the  cleavage  products  previously 
obtained  by  Maly  (with  the  exception  of  amidovalerianic  acid  and  isogly- 
cerinic  acid),  besides  also  acetic,  propionic,  butyric  acids,  benzaldehyde  and 
pyridin. 

As  in  oxidation  with  potassium  permanganate,  so  also  may  the  proteids 
be  changed  by  the  action  of  the  halogens,  namely,  so  that  they  contain  no 
sulphur  which  can  be  split  off  by  alkali,  or  give  Millox's  reaction,  nor 
yield  tyrosin  as  a  cleavage  product.  By  the  action  of  chlorine,  bromine, 
and  iodine  on  proteids  the  halogens  pass  into  more  or  less  firm  union 
with  the  proteid  (Loew,  Blum,  Blum  and  Vaubel,  Liebreciit,  Hop- 
kins and  Brook,  Hofmeister),  and  it  is  possible  to  prepare  derivatives 

'  Sitzuiigsber.  d.  k.  Akad.  d.  Wisseusch.  Wieu,  Abth.  II,  1885,  and  Abth.  II,  1888. 
Also  MoniUshefte  f.  Cliem.,  Bdd.  6  and  9.  See  also  Boudzynski  and  Zoja,  Zeitacbr.  f. 
pbysiol.  Cheiu..  Bd.  19. 

*  Zeilschr.  f.  physiol.  Cbem.,  Bd.  26, 


24  THE  PROTEIN  SUBSTANCES. 

with  different  bat  constant  quantities  of  halogen  according  to  the  method 
resorted  to  (Hopkins  and  Pinkus  '). 

On  the  putrefaction  of  proteids,  as  well  as  their  decomposition  by 
means  of  acids  or  alkalies  and  also  by  certain  enzymes,  among  other 
products  amido-acids  are  produced,  and  these  have  a  certain  significance  for 
the  probable  formation  of  the  proteids.  It  is  more  than  likely  that  in  the 
synthesis  of  proteids  in  the  plant  from  the  ammonia  or  the  nitric  acid  of 
the  soil,  amido-acids  or  acid  amids,  among  which  asparagin  plays  an  impor- 
tant role,  are  prodnced;  and  from  these  the  albuminous  bodies  are  derived 
by  the  action  of  glucose  or  other  non-nitrogenized  combinations. 

The  three  basic  bodies  lysin,  arginin,  and  histidin  are  formed,  as  shown 
by  KossEL,  as  cleavage  products  of  a  gronp  of  bodies,  the  protamins, 
which  were  first  shown  by  Miescher  and  then  by  Kossel  to  occur  in  fish- 
sperm  as  combinations  of  nucleic  acid  (see  Chapter  V).  The  protamins 
(see  Appendix  to  this  Chapter)  are  basic  bodies  which  have  some  reactions 
in  common  with  the  proteids,  but  which  yield  no  amido-acids  on  cleavage. 
As  they  yield  the  same  basic  products  as  proteids,  they  may,  as  suggested  by 
KossEii,  be  considered  to  a  certain  extent  as  the  nucleus  of  the  proteid 
moledule,  and  the  varions  proteids  may  be  derived  from  this  nuclens  by  the 
addition  of  other  atomic  groups,  monoamido  acids  and  others.^ 

The  question  as  to  the  preparation  of  proteid-like  substances  synthetically  stands  in 
close  relation  with  the  above  stiitemeuts.  In  this  connection  we  must  mention  in  the 
first  place  the  researches  of  Grimaux,  and  then  SchDtzenberger  and  Pickerikq,' wha 
by  the  action  of  phosphorus  penlchluride  or  peutoxiile  on  vaiious  amido  acids  or  by  heat- 
ing aliiiie,  were  able  to  prepare  bodies  such  as  biuret,  alloxan,  xanthin,  or  ammonium 
substances  either  alone  or  mixed  with  other  bodies.  These  substancos  are  similar 
in  several  ways  with  the  proteids,  although  they  cannot  be  considered  as  genuine  pro- 
teids. The  syntheses  of  gelatin  or  nlbumose-like  substances  published  by  Lilfen- 
FEivD'*  will  undoubtedly  be  of  much  greater  importance  when  they  have  been  substanti- 
ated by  others. 

The  animal  albuminous  bodies  are  odorless,  tasteless,  and  ordinarily 
amorphous.  The  crystalloid  spherules  {^Dotterpldttchen)  occurring  in  the 
eggs  of  certain  fishes  and  amphibians  do  not  consist  of  pure  proteids,  but  of 
proteids  containing  large  amounts  of  lecithin,  which  seems  to  be  combined 

'  Loew,  Journ.  f.  prakt.  Chem.  (N.  F.),  Bd.  31  ;  Blum,  Mllnch.  med.  Wochenschr., 
1896  ;  Blum  and  Vaubel,  Journ.  f.  prakt.  Chem.  (N.  F.),  Bd.  57  ;  Liebrecht,  Ber.  d. 
deutsch.  chem.  Gesellsch.,  Bd.  30;  Hopkins  and  Brook,  Journ.  of  Physiol.,  Vol.  22; 
Hopkins  and  Pinkus,  Ber.  d.  deiitsch.  chem.  Gesellsch.,  Bd.  31  :  Hofmeister,  Zeit.«rhr. 
f.  physiol.  Chem.,  Bd.  24. 

'  Kossel,  Sitzungsber.  d.  Gesellsch.  zur  Beford.  d.  ges.  Naturwissensch.  zu  Maibuig, 
No.  5,  1897,  and  Zeitschr.  f.  phy.siol.  Chem.,  Bd.  25. 

'  See  Pickering,  Kings  College,  London,  Physiol.  Lab.  Collect.  Papers,  1897,  where 
the  works  of  Griina\ix  are  also  cited  ;  also  Journal  of  Physiol.,  Vol.  18,  and  Proceed. 
Roy.  Soc.  Vol.  60,  1897  ;  Schiitzenberger,  Compt.  rend.,  Tomes  106  and  112. 

*  Du  Bois-Peymond's  Arch.,  1894  ;  Phy.siol.  Abth..  S.  383  and  555. 


REACTIONS  OF   TlIK  PliOTEIDS.  25 

with  mineral  substances.  CrystuUine  proteids '  liave  been  prepared  from 
seeds  of  varions  plants,  and  lately  crystallized  animal  proteids  (see  seral- 
bumin and  ovalbumin,  Chapters  \1  and  XIII)  have  also  been  j)repared. 
In  the  dry  condition  the  albuminous  bodies  appear  as  a  white  powder,  or 
when  in  thin  layers  as  yellowish,  hard,  transparent  plates.  A  few  are 
soluble  in  water,  others  only  soluble  in  salt  or  faintly  alkaline  or  acid  solu- 
tions, while  others  are  insoluble  in  these  solvents.  All  albuminous  bodies 
Avhen  burnt  leave  an  ash,  and  it  is  therefore  questionable  whether  there 
exists  any  proteid  body  which  is  soluble  in  water  without  the  aid  of  mineral 
substances.  Xevertheless  it  has  not  been  thus  far  successfully  proved  that 
a  native  albuminous  body  can  be  prepared  perfectly  free  from  mineral  sub- 
stances without  changing  its  constitution  or  its  properties.'  The  albumi- 
nous bodies  are  in  most  cases  strong  colloids.  They  diffuse,  if  at  all,  only 
very  slightly  through  animal  membranes  or  parchment-paper,  and  the 
proteids  therefore  have  a  very  high  osmotic  equivalent.  All  albuminous 
bodies  are  optically  active  and  turn  the  ray  of  polarized  light  to  the  left. 

On  heating  a  proteid  solution  it  is  changed,  the  temperature  necessary 
depending  upon  the  proteid  present,  and  with  proper  reactions  of  the  solu- 
tion and  nnder  favorable  external  conditions — as,  for  example,  in  the 
presence  of  neutral  salts — most  proteids  separate  in  the  solid  state  as 
"coagulated"  proteids.  The  different  temperatures  at  which  various 
proteids  coagulate  in  neutral  salt  solutions  give  in  many  cases  a  good  means 
of  detecting  and  sejiarating  these  various  bodies.  The  views  in  regard  to 
the  use  of  these  means  are  divided.' 

The  general  reactions  for  the  proteids  are  very  numerous,  but  only  the 
most  important  will  be  given  here.  To  facilitate  the  study  of  these  they 
have  been  divided  into  the  two  following  groups: 

A.  Precipitation  Reactions  of  the  Proteid  Bodies. 

1.  Coagnlaiion  Test. — An  alkaline  proteid  solution  does  not  coagulate 
ou  boiling,  a  neutral  solution  only  partly  and  incompletely,  and  the  reaction 

'  See  Maschke,  Journ.  f,  prakt.  Chem.,  Bd.  74;  Drecbsel,  ibid.  (N.  F.),  Bd.  19; 
Griibler,  ibid.  (N.  F.),  Bd.  23  ;  Ritthausen,  ibid.  (X.  F.),  Bd.  25  ;  Scbmiedeberg,  Zeit- 
scbr.  f.  pbysiol.  Cbem.,  Bd.  1  ;  Weyl,  ibid.,  Bd.  1. 

*  See  E.  Haruack,  Ber.  d.  deutscb.  cbem.  Gesellscb.,  Bdd.  23,  23,  25  ;  Weiigo, 
Pflilger's  Arcbiv,  Bd.  48  ;  Billow,  ibid.,  Bd.  58. 

*  See  Halliburton,  Journ.  of  Pbysiol.,  Vols.  5  and  11  ;  Coriu  and  Berard,  Bull,  de 
I'Acad.  roy.  de  Belg.,  15;  Haycraft  and  Duggau,  Brit.  Med.  Journ..  1890,  and  Proc. 
Roy.  Soc.  Ed.,  1889  ;  Coria  and  Ansiau.x,  Bull,  de  I'Acad.  roy.  de  Belg.,  Tome  21  ;  L. 
Fredericq,  Centralbl  f.  Pbysiol.,  Bd.  3;  Haycraft,  ibid.,  Bd.  4  ;  Hewlett,  Journ.  of 
Pbysiol.,  Vol.  13  ;  Ducleu.K,  Annal.  Institut  Pasteur,  7.  In  regard  to  the  relationsbip 
of  tbe  neutral  salts  to  tbe  beat  coagulation  of  albumins  see  also  Starke,  Sitzungsber.  d. 
Gesellscb.  f.  Morpb.  u.  Pbysiol.  in  Miincben,  1897. 


26  THE  PROTEIN  SUBSTANCES. 

mnst  therefore  be  acid  for  coagulation.  The  neutral  liquid  is  first  boiled 
and  then  the  proper  amount  of  acid  added  carefully.  A  lloccalent  precipi- 
tate is  formed,  and  if  properly  done  the  filtrate  should  be  water-clear.  If 
-dilute  acetic  acid  be  used  for  this  test,  the  liquid  must  first  be  boiled  and 
then  1,  2,  or  3  drops  of  acid  added  to  each  10-15  c.  c,  depending  on  the 
amount  of  profceid  present,  and  boiled  before  the  addition  of  each  drop.  If 
dilute  nitric  acid  be  used,  then  to  10-15  c.  c.  of  the  previously  boiled  liquid 
15-20  drops  of  the  acid  must  be  added.  If  too  little  nitric  acid  be  added,  a 
soluble  combination  of  the  acid  and  proteid  is  formed  which  is  precipitated 
by  more  acid.  A  proteid  solution  containing  a  small  amount  of  salts  must 
first  be  treated  with  about  l<fo  ISTaCl,  since  the  heating  test  may  fail, 
especially  on  using  acetic  acid,  in  the  presence  of  only  a  slight  amount  of 
proteid.  2.  Behavior  toiuards  Mineral  Adds  at  Ordinary  Temperatures. 
The  proteids  are  precipitated  by  the  three  ordinary  mineral  acids  and  by 
metaphosphoric  acid,  but  not  by  orthophosphoric  acid.  If  nitric  acid  be 
placed  in  a  test-tube  and  the  proteid  solution  be  allowed  to  flow  gently 
thereon,  a  white  opaque  ring  of  precipitated  proteid  will  form  where  the 
two  liquids  meet  (Hellek's  albumin  test).  3.  Precijjitation  ly  Metallic 
Salts:  Copper  sulphate,  neutral  and  basic  lead  acetate  (in  small  amounts), 
mercuric  chloride,  and  other  salts  precipitate  proteid.  On  this  is  based  the 
•use  of  proteids  as  antidotes  in  poisoning  by  metallic  salts.  4.  Precipitation 
liy  Ferro-  or  Ferncyanide  of  Potassium  in  Acetic  Acid  Solution.  In  these 
tests  the  relative  quantities  of  reagent,  proteid,  or  acid  do  not  interfere  with 
the  delicacy  of  the  test.  5.  Precipitation  by  Neutral  Salts,  such  as  Na^SO^ 
or  XaCl,  when  added  to  saturation  to  the  liquid  acidified  with  acetic  acid 
or  hydrochloric  acid.  6.  Precipitation  ly  Alcohol.  The  solution  mast  not 
be  alkaline,  but  must  be  either  neutral  or  faintly  acid.  It  must,  at  the 
same  time,  contain  a  sufficient  quantity  of  neutral  salts.  7.  Precipitation 
Tjy  Tannic  Acid  in  acetic-acid  solutions.  The  absence  of  neutral  salts  or 
the  presence  of  free  mineral  acids  may  not  cause  the  precipitate  to  appear, 
but  after  the  addition  of  a  sufficient  quantity  of  sodium  acetate  the  precipi- 
tate will  in  both  cases  appear.  8.  Precipitation  hy  Phospho-tungstic  or 
PhospUo-molyhdic  Acids  in  the  presence  of  free  mineral  acids.  Potassium,- 
mercuric  iodide  srnd  potassiiwi-Msmiith  iodide  precipitate  albumin  solutions 
acidified  with  hydrochloric  acid.  9.  Precipitation  by  Picric  Acid  in  solu- 
tions acidified  by  organic  acids.  10.  Precipitation  by  Trichloracetic  Acid 
in  2-5^  solutions,  and  11.  by  Salicylsulphonic  Acid.  The  proteids  are 
precipitated  by  nucleic  acid,  tanrocholic  and  chondroitin-sulphuric  acid  in 
acid  solutions. 


REACTIONS  OF  THE  PROTEIDS.  27 


B.  Color  Reactions  for  Proteid  Bodies. 

1.  Millori^s  reaction.^  A  solntion  of  mercury  in  nitric  acid  containing 
some  nitrous  aciil  gives  a  precipitate  with  proteid  solutions  which  at  the 
ordinary  temperature  is  slowly,  hut  at  the  hoiling-point  more  quickly, 
colored  red;  and  the  solution  may  also  he  colored  a  feeble  or  bright  red. 
Solid  albuminous  bodies,  when  treated  by  this  reagent,  give  the  same  colora- 
tion. This  reaction,  whicli  depends  on  the  presence  of  the  aromatic  group 
in  the  proteid,  is  also  given  by  tyrosin  and  other  benzol  derivatives  with  a 
hydroxyl  group  in  the  benzol  nucleus.''  2.  Xatdhoproteic  reaction.  With 
strong  nitric  acid  the  albuminous  bodies  give,  on  heating  to  boiling,  yellow 
Hakes  or  a  yellow  solution.  After  saturating  with  ammonia  or  alkalies  the 
color  becomes  orange-yellow.  3.  Adainkiewicz''  reaction.  If  a  little  proteid 
is  added  to  a  mixture  of  1  vol.  concentrated  sulphuric  acid  and  2  vols, 
glacial  acetic  acid  a  reddish-violet  color  is  obtained  slowly  at  ordinary  tem- 
l)eratnres,  but  more  quickly  on  heating.  Gelatin  does  not  give  this 
reaction.  4.  Biuret  test.  If  a  proteid  solution  be  first  treated  with 
caustic  potash  or  soda  and  then  a  dilute  copper  sulphate  solution  be  added 
drop  by  drop,  first  a  reddish,  then  a  reddish-violet,  and  lastly  a  violet-blue 
color  is  obtained.  5.  Proteids  are  soluble  on  heating  with  concentrated 
hydrochloric  acid,  producing  a  violet  color,  and  when  they  are  previously 
boiled  with  alcohol  and  then  washed  with  ether  (Liebekmaxx  ')  they  give 
a  beautiful  blue  solution.  6.  With  concentrated  sulphuric  acid  and  sugar 
{in  small  quantities)  the  albuminous  bodies  give  a  beautiful  red  coloration. 
Eli,iott  *  has  suggested  the  following  as  a  reaction  for  protein  substances. 
If  dilute  sulphuric  acid  (20  vols,  in  100  vols,  water)  is  allowed  to  act  on  the 
protein  substances  a  bluish-violet  color  or  a  bluish-violet  solntion  is  obtained 
on  gradual  concentration  of  the  acid  at  ordinary  temperature.  Dilute 
hydrochloric  acid  acts  in  the  same  way.  The  solution  shows  a  spectrum 
somewhat  different  from  those  obtained  by  Pettenkofer's,  Liebermaxn's 
or  Adamkiewicz's  reactions.  These  color  reactions  apply  to  all  albuminous 
bodies. 

Mauy  of  these  color  reactions  are  obtained  as  shown  by  Salkowski  ^  by  the  aromatic 
cleavage  products  of  the  proteids.  Millon's  reaction  is  only  obtained  by  the  substances 
of  the  phenol  group  ;  the  Xanthopkoteic  reaction  by  the  phenol  group  and  skatol  or 

'  The  reagent  is  obtained  in  the  following  way  :  1  pt.  mercury  is  dissolved  in  2  pts. 
of  nitric  acid  (of  sp.  gr.  1.42),  first  when  cold  and  later  by  warming.  After  complete 
solution  of  the  mercury'  add  1  volume  of  the  solution  to  3  volumes  of  water.  Allow 
this  to  stand  a  few  hours  and  decant  the  supernatant  liquid. 

*  See  O.  Nasse,  Sitzungsb.  d.  Naturforsch.  Gesellsch.  zu  Halle,  1879 ;  Vaubel  and 
Blum,  Journ.  f.  prakt.  Chem.  (N.  F.).  Bd.  57. 

»  Centralbl.  f.  d.  med.  Wissensch.,  1887. 

'  .lourn.  of  Physiol..  Vol.  23. 

'  Zeitschr.  f,  physiol.  Chem.,  Bd.  12,  S.  215. 


28  THE  PROTEIN  SUBSTANCES. 

skatolcarbonic  acid.  Liebermakn's  reaction  is  uot  given  by  any  of  the  :iromatic  split- 
ting products.  Adamkiewicz's  reaction  is  only  given  by  the  iiidol  group,  especially 
skatolcarbonic  acid.  This  reaction  i.,  considered  as  a  furfurol  reaction  bioughl  about  by 
a  carbohydnue  group  as  well  as  an  aromatic  group  in  the  proteid.  Liebekmann's  reac- 
tion, as  well  as  the  reaction  with  sulphuric  acid  and  sugar,  seems  at  least  to  be  a  furfurol 
reaction.  The  biuret  reaction  is  uot  only  given  by  proteid,  pro'.amin  and  biuret,  but 
also  by  artificially-prepared  colloids  (Gkimaux,  Pickering)  and  many  diauiids.  Ac- 
cording to  H.  ScHiFF,'  the  presence  of  at  least  two  groups  (— CO.NHo)  uiiiied  in  the 
molecule  to  a  single  atom  of  carbon  or  nitrogen,  or  by  one  or  more  groups  (—  C'O.NH) 
united  in  open  chain.  Both  CO.NH3  groups  mny  also  be  directly  united,  as  in  oxaniid. 
Asparagin,  a  natural  decomposition  product  of  proteids,  also  gives  the  biuret  reaction. 
Uobilin  also  gives  a  reaction  similar  to  the  biuret  reaction,  and  the  fact  that  a  body  gives 
the  biuret  reaction  is  not  only  sufficient  proof  of  its  being  a  protein. 

The  delicacy  of  the  same  reagent  differs  for  the  different  albuminotis 

bodies,  and  on  this  acconnt  it  is  impossible  to  give  the  degree  of  delicacy 

for  each  reaction  for  all  albuminous  bodies.     Of  the  precipitation  reactions 

Heller's  test    (if  we  eliminate   the  peptones  and  certain  albnmoses)   is 

recommended  in  the  first  place  for  its  delicacy,  though  it  is  not  the  most 

delicate  reaction,  and  because  it  can  be  performed  so  easily.     Among  the 

precipitation  reactions,  that  with  basic   lead  acetate  (when  carefully  and 

exactly  executed)  and  the  reactions  6,  7,  8,  9,  and  11  are  the  most  delicate. 

The  color  reactions  1  to  4  show  great  delicacy  in  the  order  in  which  they  are 

given^ 

No  proteid  reaction  is  in  itself  characteristic,  and,  therefore,  in  testing 
for  proteids  one  reaction  is  not  sufficient,  but  a  number  of  precipitation  and 
color  reactions  must  be  employed. 

For  the  quantitative  estimation  of  coagulable  proteids  the  determination 
by  boiling  with  acetic  acid  can  be  performed  with  advantage,  since,  by 
operating  carefully,  it  gives  exact  results.  Treat  the  proteid  solution  with 
a  1-2^  common-salt  solation,  or  if  the  solution  contains  large  amounts  of 
proteid  dilute  with  the  proper  quantity  of  the  above  salt  solution,  and  then 
carefully  neutralize  with  acetic  acid.  Now  determine  the  quantity  of  acetic 
acid  necessary  to  completely  precipitate  the  proteids  in  small  measured 
portions  of  the  neutralized  liquid  which  have  previously  been  heated  on  the 
water-bath,  so  that  the  filtrate  does  not  respond  with  Heller's  test.  Now 
warm  a  larger  weighed  or  measured  quantity  of  the  liquid  on  the  water- 
bath,  and  add  gradually  the  required  quantity  of  acetic  acid,  with  constant 
stirring,  and  continue  tlie  heat  for  some  time.  Filter,  wash  with  water, 
extract  with  alcohol  and  then  wnth  ether,  dry,  weigh,  incinerate  and  weigh 
again.  With  proper  work  the  filtrate  should  not  give  Heller's  test.  This 
metliod  serves  in  most  cases,  and  especially  so  in  cases  where  other  bodies 
are  to  be  quantitatively  estimated  in  the  filtrate. 

The  precipitation  by  means  of  alcohol  may  be  used  in  the  quantitative 
estimation  of  proteids.  The  liquid  is  first  carefully  neutralized,  treated 
with  some  NaCl  if  necessary,  and  then  alcohol  added  until  the  solution 
contains  70-80  vol.  per  cent  anhydrous  alcohol.  The  precipitate  is  collected 
on  a  filter  after  24  hours,  extracted  with  alcohol  and  ether,  dried,  weighed, 
incinerated  and  again  Aveighed.  This  method  is  only  applicable  to  liquids 
which  do  not  contain  any  other  substances,  like  glycogen,  which  are  insolu- 
ble in  alcohol. 

'  Ber.  d.  doutsch.  chem.  Gesellsch.,  Bd.  29. 


SVNOrSLS  OF  PRO  PERT  IKS  OF  FROTEIDS.  2'J 

In  both  these  methods  small  fiuantities  of  proteids  may  remain  in  t!ie 
filtrates.  These  traces  may  be  determined  as  follows:  Concentrate  the 
filtrate  sulliciejitly,  remove  any  separated  fat  by  shaking  with  ether,  and 
then  precipitate  with  tannic  acid.  Approximately  O;}^  of  the  tannic  acid 
precipitate,  washed  with  cold  water  and  then  dried,  may  be  considered  as 
proteid. 

In  many  cases  good  resnlts  may  be  obtained  by  precipitating  all  the 
proteid  with  tannic  acid  and  determining  the  nitrogen  in  the  washed  pre- 
cipitate by  means  of  K.teldaiil's  method.  On  multiplying  the  quantity  of 
nitrogen  found  by  0.25  we  obtain  the  quantity  of  proteid. 

The  remov^al  of  proteids  from  a  solution  may  in  most  cases  be  performed 
by  boiling  with  acetic  acid.  Small  amounts  of  proteid  which  remain  in  the 
filtrates  may  be  separated  by  boiling  with  freshly  precipitated  lead  carbonate 
or  with  ferric  acetate,  as  described  by  IIofmeisteu.'  If  the  liquid  cannot 
be  boiled,  the  proteid  may  be  precipitated  by  the  very  careful  addition  of 
lead  acetate,  or  by  the  addition  of  alcohol.  If  the  liquid  contains  sub- 
stances which  are  precipitated  by  alcohol,  such  as  glycogen,  then  tiie  proteid 
may  be  removed  by  the  alternate  addition  of  potassium-mercuric  iodide  and 
hydrochloric  acid  (see  Chapter  VIII,  on  Glycogen  Estimation),  or  also  by 
trichloracetic  acid  as  suggested  by  Ohermayer  and  Frankel.^ 

Synopsis  of  the  Most  Important  Properties  of  the  Different  Chief  Groups 

of  Proteids. 

Those  proteids  which  occur  formed,  in  the  ordinary  sense,  in  the  animal 
fiuids  and  tissues,  and  which  can  be  isolated  from  these  without  losing  their 
original  properties  by  different  chemical  means,  are  called  native  proteids. 
Xew  modifications,  with  other  properties,  may  be  obtained  from  these 
native  proteids  by  the  action  of  heat,  various  chemical  reagents,  such  as 
acids,  alkalies,  alcohol,  and  others,  as  also  by  proteolytic  enzymes.  These 
new  proteids  are  called  modified  '  proteids,  in  contradistinction  to  the 
native  proteids.  The  albumins,  globulins,  and  nucleoalbumins,  as  given  in 
the  scheme  on  page  1(3,  belong  to  the  native  proteids,  while  the  acid  and 
alkali  albuminates,  albumoses,  peptones,  and  the  coagulated  jiroteids  belong 
to  the  modified  proteids. 

The  native  proteids  may  be  precipitated  by  sufficient  amounts  of  neutral 
salts  without  changing  their  properties,  although  the  various  proteids  act 
differently  with  different  neutral  salts.  Some  are  precipitated  by  NaCl, 
others  only  by  MgSO^,  and  still  others  by  only  (NHJ^SO^,  which  is  the 
precipitant  for  nearly  all  proteids.  These  various  properties,  as  also  the 
different  solubility  in  water  and  dilute  salt  solution,  are  used  at  the  present 
time  to  differentiate  between  the  various  proteids  and  groups,  although  it 

'  Zeitschr.  f.  physiol.  Chem.,  Bdd.  2  and  4. 

»  Obermayer,  Wieu.  med.  Jahrbiicher,  1888;  Fritnkel,  PflUger's  Arch.,  Bdd.  52 
and  55. 

'  The  word  denaturierung  as  used  by  Neumeister  and  the  author  is  translated  by  the 
word  modified,  as  it  best  expresses  the  meaning.     The  word  derived  might  also  be  used. 


30  TEE  PROTEIN  SUBSTANCES. 

must  be  stated  that  these  differences  are  only  relative  and  are  often 
uncertain. 

Albumins.  These  bodies  are  soluble  in  water  and  are  not  precipitated 
by  the  addition  of  a  little  acid  or  alkali.  They  are  precipitated  by  the 
addition  of  large  quantities  of  mineral  acids  or  metallic  salts.  Their  solu- 
tion in  water  coagulates  on  boiling  in  the  presence  of  neutral  salts,  but  a 
weak  saline  solution  does  not.  If  NaCl  or  MgSO^  is  added  to  saturation  to 
a  neutral  solution  in  water  at  the  normal  temperature  or  at  -f  30°  C.  no 
precipitate  is  formed;  but  if  acetic  acid  is  added  to  this  saturated  solution 
the  albumin  readily  separates.  When  ammonium  sulphate  is  added  in 
substance  to  saturation  to  an  albumin  solution  a  complete  precipitation 
occurs  at  ordinary  temperature.  Of  all  the  albuminous  bodies  the  albumins 
are  the  richest  in  sulphur,  containing  from  1.6^  to  2.2^. 

Globulins.  These  albuminous  bodies  are  insoluble  in  water,  but  dissolve 
in  dilute  neutral  salt  solutions.  The  globulins  are  precipitated  unchanged 
from  these  solutions  by  sufficient  dilution  with  water,  and  on  heating  they 
coagulate.  The  globulins  dissolve  in  water  on  the  addition  of  very  little 
acid  or  alkali,  and  on  neutralizing  the  solvent  they  precipitate  again. 

The/  solution  in  a  minimum  amount  of  alkali  is  precipitated  by  carbon 
dioxide,  but  the  precipitate  may  be  redissolved  by  an  excess  of  the  precipi- 
tant. The  neutral  solutions  .of  the  globulins  containing  salts  are  partly  or 
completely  precipitated  on  saturation  with  NaCl  or  MgSO^  in  substance  at 
normal  temperatures.  The  globulins  are  completely  precipitated  by  saturat- 
ing with  ammonium  sulphate.  The  globulins  contain  an  average  amount 
of  sulphur,  not  below  Ifo. 

A  sharp  line  between  the  globulins  on  one  side  and  the  artificial  albuminates  on  the 
other  can  hardly  be  drawn.  The  albuminates  are,  indeed,  as  a  rule  insoluble  in  dilute 
common-salt  solutions  ;  but  an  albuminate  may  be  prepared  by  the  action  of  strong  alkali 
which  is  soluble  in  common-salt  solutions  immediately  after  precipitatiou.  We  also 
have  globulins  which  are  insoluble  in  NaCl  after  having  been  in  contact  with  water  for 
some  time. 

Nucleoalbumins.  This  group  of  phosphorized  proteids  are  found  widely 
diffused  in  both  the  animal  and  vegetable  kingdoms.  The  nucleoalbumins 
are  found  in  organs  abounding  in  cells,  but  they  also  occur  in  secretions  and 
sometimes  in  other  fluids  in  apparent  solution  as  destroyed  and  altered 
protoplasm.  The  nucleoalbumins  behave  like  rather  strong  acids;  they  are 
nearly  insoluble  in  water,  but  dissolve  easily  with  the  aid  of  a  little  alkali. 
Such  a  solution,  neutral  or,  indeed,  a  faintly  acid  one,  does  not  coagulate 
on  boiling.  The  nucleoalbumins  resemble  the  globulins  and  the  albumi- 
nates (see  below)  in  solubility  and  precipitation  properties,  but  differ  from 
them  in  being  hardly  soluble  in  neutral  salts.  The  most  important  differ- 
ence between  the  nucleoalbumins,  the  globulins,  and  the  albuminates  is  that 
the  nucleoalbumins  contain  phosphorus.  They  also  differ  from  the  other 
genuine  proteids  by  this  quantity  of  phosphorus  and  stand  on  this  account 


ALKALI  AND   ACID  ALBUMINATES.  31 

close  to  the  nncleoproteids.  They  differ  from  the  hitter  in  that  thej  do 
uot  yield  xunthiii  bodies  on  cleavage.  On  peptic  digestion  most  nucleo- 
albumins  yield  a  proteid  substance  very  rich  in  phosphorus,  which  has  been 
called  para-  or  pseudonuclein  in  contradistinction  to  the  true  nucleins  (see 
Chapter  \').  According  to  Likhermanx  '  pseudonuclein  is  a  combination 
of  proteid  with  metaphosphoric  acid.  The  nucleoalbumins  seem  to  contain 
some  iron. 

The  st'iKiratioii  of  pseudouuclein  iu  the  peptic  digestion  of  nucleoalbumins  canuol  be 
considered  as  positively  chanicterislic  of  the  nucleoalbuiniu  group.  The  extent  of  such 
a  cleavage  is  dependent  upon  the  intensity  of  the  pepsin  digestion,  upon  the  degree  of 
acidity  and  tliu  relationship  between  the  nucleoalbuuiius  and  tiie  digestive  lluids.  The 
separation  of  a  pseudonuclein  may,  as  shown  by  Salkowski,  not  occur  even  in  the 
digestion  of  ordinary  casein,  and  AVkoui.ewski  did  not  obtain  any  pseudonuclein  at  all 
iu  the  digesti(.u  of  tlie  casein  from  human  milk.  In  the  digestion  of  vegetable  nucleo- 
alburnin  Wiman'^  has  also  shown  that  the  fact  whether  we  obtain  a  great  deal  of  pseudo- 
nuclein or  not  is  dependent  \ipon  the  way  in  which  the  digestion  is  performed.  The 
most  essential  characteristic  of  this  group  of  proteids  is  that  they  contain  a  given  amount 
of  phosphorus,  and  the  absence  of  xantbin  bases  among  their  cleavage  products. 

The  nucleoalbumins  are  often  confounded  with  nncleoproteids  and  also 
with  phosphorized  glycoproteids.  From  the  first  class  they  differ  by  not 
yielding  any  xanthin  bodies  when  boiled  with  acids,  and  from  the  second 
group  by  not  yielding  any  reducing  substance  on  the  same  treatment. 

Lecithalbumins.  In  the  preparation  of  certain  proteih  substances  products  are  often 
obtained  containing  lecithin,  and  this  lecithin  can  only  be  removed  with  difficult}'  or 
incompletely  by  a  mixture  of  alcohol  and  ether.  Ovovitellin  is  such  a  protein  body  con- 
taining considerable  lecithin,  and  Hoppe-Seyleh  considers  it  a  combination  of  proteid 
and  lecithin.  Liebermann^  has  obtained  proteids  containing  lecithin  as  an  insoluble 
residue  on  the  peptic  digestion  of  mucous  membranes  of  the  stomach,  liver,  kidneys, 
lungs,  and  spleen.  He  considers  them  as  combinations  of  proteid  and  lecithin  and  calls 
them  lecithaLbuminn. 

Alkali  and  Acid  Albuminates.  Xative  proteids  may,  as  the  researches 
of  recent  date  of  several  investigators  such  as  Sjoqvist,  0.  Cohxheim, 
BuGARSZKY  and  L.  Lieberm-\.nx^  show,  enter  into  combinations  with  acids 
and  alkalies  without  changing  their  properties.  On  the  contrary,  by  the 
sufficiently  strong  action  of  these  reagents  a  modification  may  take  place. 
By  the  action  of  alkalies  all  native  albuminous  bodies  are  converted,  with  the 
elimination  of  nitrogen  or  by  the  action  of  stronger  alkali,  also  with  the 
emission  of  sulphur,  into  a  new  modification,  called  alkali  albuminate, 
whose  specific  rotation  is  increased  at  the  same  time.  If  caustic  alkali  in 
substance  or  in  strong  solution  be  allowed  to  act  on  a  concentrated  proteid 
solution,  such  as  blood-serum  or  egg-albumin,  the  alkali  albuminate  may  be 

'  Ber.  (1.  deutsch.  chem.  Gesellsch.,  Bd.  21. 

'  Salkowski,  Ptillger's  Arch.,  Bd.  63  ; — Wroblewski,  Beitriige  zur  Kenntniss  des 
Frauenkaseius.     Inaug.-Diss.  Bern,  1894; — Wiman,  Upsala  Liikaref.  FOrh.,  N.  F.  2. 

"  Hoppe-Seyler,  Med.  chem.  Untersuch.,  1868  ;  also  Zeitschr.  f.  physiol.  Chem.,  Bd. 
13,  S.  479;  Liebermann,  Pflilger's  Archiv,  Bdd.  50  and  54. 

*  Sjoqvist,  Skand.  Arch.  f.  Physiol.,  Bd.  5  ;  O.  Cohuheim,  Zeitschr.  f.  Biologie,  Bd. 
33  ;  Bugarszky  and  Liebermann,  Pfliiger's  Arch.,  Bd.  72. 


32  THE  PROTEIN  SUBSTANCES. 

obtained  as  a  solid  jelly  wliicli  dissolves  in  water  on  heating,  and  which  is 
called  "  Lieberkuhn's  solid  alkali  albuminate."  By  the  action  of  dilute 
caustic  alkali  solutions  on  dilute  proteid  solutions  we  have  alkali  albumi- 
nates formed  slowly  at  the  ordinary  temperature,  but  more  rapidly  on 
heatin<7-.  These  solutions  may  be  modified  by  the  source  of  the  proteid 
acted  upon,  and  also  by  the  extent  of  the  action  of  the  alkali,  but  still  they 
have  certain  reactions  in  common. 

If  proteid  is  dissolved  in  an  excess  of  concentrated  hydrochloric  acid,  or 
if  we  digest  a  proteid  solution  acidified  with  1-2  p.  m.  hydrochloric  acid  in 
the  warmth,  or  digest  the  proteid  alone  with  pepsin  hydrochloric  acid,  we 
obtain  new  modifications  of  proteid  which  indeed  may  show  somewhat  vary- 
ing properties,  bat  have  certain  reactions  in  common.  These  modifications, 
which  may  be  obtained  in  a  solid  gelatinous  condition  on  sufficient  concen- 
tration, are  called  acid  albuminates  or  acid  albumins,  and  sometimes 
syntonin,  though  we  prefer  to  call  that  acid  albuminate  syntonin  which  is 
obtained  by  extracting  muscles  with  hydrochloric  acid  of  1  p.  m.  F.  GoLD- 
SCHMIDT  '  has  shown  in  the  action  of  acids  on  ovalbumin  that  even  in  very 

dilute  solutions  of  acid  f:T-;HCl)  secondary  albumoses  are  produced  at  the 
\1G         / 


same  time  as  acid  albuminates,  which  shows  that  the  acid  albuminate  forma- 
tion ia  accompanied  by  the  splitting  off  of  albumoses.  He  also  found  that 
the  formation  of  secondary  albumoses  did  not  require  the  previous  formation 
of  primary  albumoses.  The  extent  as  to  the  formation  of  acid  albuminate, 
hemiprotein  (Kuhne's  antialbuminate),  various  albnmoses,  peptones,  and 
further  cleavage  products  is  essentially  dependent  upon  the  temperature 
and  upon  the  concentration  of  the  acid. 

The  alkali  and  acid  albuminates  have  the  following  reactions  in 
common:  They  are  nearly  insoluble  in  water  and  dilute  common-salt  solu- 
tion (see  page  30),  but  they  dissolve  readily  in  water  on  the  addition  of  a 
Tery  small  quantity  of  acid  or  alkali.  Such  a  solution  or  one  nearly  neutral 
does  not  coagulate  on  boiling,  but  is  precipitated  at  the  normal  temperature 
on  neutralizing  the  solvent  by  an  alkali  or  an  acid.  A  solution  of  an  alkali 
or  acid  albuminate  in  acid  is  easily  precipitated  on  saturating  with  NaCl, 
but  a  solution  in  alkali  is  precipitated  with  difficulty  or  not  at  all,  according 
to  the  amount  of  alkali  it  contains.  Mineral  acids  in  excess  precipitate 
solutions  of  acid  as  well  as  alkali  albuminates.  The  nearly  neutral  solutions 
of  these  bodies  are  also  precipitated  by  metallic  salts. 

Notwithstanding  this  agreement  in  the  reactions,  the  acid  and  alkali 
albuminates  are  essentially  different,  for  by  dissolving  an  alkali  albuminate 
in  some  acid  no  acid  albuminate  solution   is   obtained,  nor   is  an   alkali 

•  Ueber  die  Einwirkung  von  Siluron  auf  Eiweissstoffe.  Inaug.-Diss.  Strassburg, 
1898. 


ALBUMOSES  AND  PEPTONES.  33 

albuminate  formed  on  dissolving  an  acid  albuminate  in  water  by  the  aid  of 
a  little  alkali.  In  the  first  case  we  obtain  a  solution  of  the  combination  of 
the  alkali  albuminate  and  the  acid  and  in  the  other  case  a  soluble  combina- 
tion of  the  acid  albuminate  with  the  alkali  added.  The  chemical  process 
in  the  modification  of  proteids  with  an  acid  is  essentially  different  from  the 
modification  with  an  alkali,  hence  the  products  are  of  a  different  kind. 
The  alkali  albuminates  are  relatively  strong  acids.  They  may  be  dissolved 
in  water  with  the  addition  of  CaCO,,  with  the  elimination  of  CO,,  which 
does  not  occur  with  typical  acid  albuminates,  and  they  show  in  opposition 
to  the  acid  albuminates  also  other  variations  which  stand  in  connection  with 
their  strongly  marked  acid  nature.  Dilute  solutions  of  alkalies  act  more 
energetically  on  jjroteids  than  do  acids  of  corresponding  concentration.  In 
the  first  case  a  part  of  the  nitrogen,  and  often  also  the  sulphur,  is  split  off, 
and  from  this  property  we  may  obtain  an  alkali  albuminate  by  tlie  action 
of  an  alkali  upon  an  acid  albuminate;  but  we  cannot  obtain  an  acid  albumi- 
nate by  the  reverse  reaction  (K.  MoRNER  '),  For  this  reason  the  calling 
of  the  modified  proteid  obtained  by  the  action  of  alkali  or  acid,  protein, 
and  the  combinations  of  this  protein  with  alkali,  alkali  albuminate  and  the 
combination  with  acid,  acid  albuminate,  leads  to  a  misunderstanding  or  to 
a  wrong  conception. 

Desamidoalbuminic  acid  is  au  alkali-albuminate  which  Schmiedeberg'  obtaiued  by 
llie  actiuu  of  such  weak  alkali  that  a  pail  of  the  uitrogen  was  evolved,  but  the  quantity 
of  sulphur  remained  the  same.  The  proteid  combination  obtaiued  by  Blum  bj'  the  action 
of  formol  on  proteid  and  called  by  bim  protogen,'^  has  similarities  with  the  alkali-albu- 
miuates  in  regard  to  solubilities  and  precipitation,  but  is  not  identical  therewith. 

The  preparation  of  the  albuminates  has  been  given  above.  By  the 
action  of  alkalies  or  acids  upon  a  proteid  solution  the  corresponding 
albuminate  may  be  precipitated  by  neutralizing  with  acid  or  alkali.  The 
washed  precipitate  is  dissolved  in  water  by  the  aid  of  a  little  alkali  or  acid, 
and  again  precipitated  by  neutralizing  the  solvent.  If  this  precipitate 
which  has  been  washed  in  water  is  treated  with  alcohol  and  ether,  the 
albuminate  will  be  obtained  in  a  pure  form. 

Albumoses  and  Peptones.  Peptones  are  designated  as  the  final  products 
of  the  decomposition  of  albuminous  bodies  by  means  of  proteolytic  enzymes, 
in  so  far  as  these  final  products  are  still  true  albuminous  bodies,  while  we 
designate  as  albumoses,  proteoses,  or  propeptones  the  intermediate  products 
produced  in  the  peptonization  of  proteids  in  so  far  as  they  are  substances 
not  similar  to  albuminates.  Albumoses  and  peptones  may  also  be  produced 
by  the  hydrolytic  decomposition  of  the  proteids  with  acids  or  alkalies,  also 
by  the  putrefaction  of  the  same.     They  may  also  be  formed  in  very  small 

'  Pdilger's  Archiv,  Bd.  17. 

•  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  39. 

'  Blum,  Zeitschr.  f.  physiol.  Chera.,  Bd.  22.  The  older  investigations  of  Loew  may 
be  found  in  Maly's  Jahresber.,  1888.  On  the  action  of  formaldehyde,  see  also  Benedi- 
centi,  Du  Bois-Rcvmond's  Arch.,  1897. 


34  THE  PROTEIN  SUBSTANCES. 

qnantities  as  by-prodncts  in  the  investigations  of  animal  fluids  and  tissues, 
and  the  question  to  what  extent  these  exist  preformed  under  physiological 
conditions  requires  very  careful  investigation. 

Between  the  peptone  which  represents  the  final  cleavage  product  and 
the  albumose  which  stands  closest  to  the  original  proteid  we  have 
undoubtedly  a  series  of  intermediate  products.  Under  such  circumstances 
it  is  a  difficult  problem  to  try  to  draw  a  sharp  line  between  the  peptone  and 
the  albumose  group,  and  it  is  just  as  difficult  to  define  our  conception  of 
peptones  and  albumoses  in  an  exact  and  satisfactory  manner. 

The  albumoses  have  been  considered  as  those  albuminous  bodies  whose 
neutral  or  faintly  acid  solutions  do  not  coagulate  on  boiling  and  which,  to 
distinguish  them  from  peptones,  were  characterized  chiefiy  by  the  following 
properties.  The  watery  solutions  are  precipitated  at  the  ordinary  tempera- 
ture by  nitric  acid  as  well  as  by  acetic  acid  and  potassium  ferrocyanide,  and 
this  precipitate  has  the  peculiarity  of  disappearing  on  heating  and  reappear- 
ing on  cooling.  If  a  solution  of  albumoses  is  saturated  with  NaCl  in 
substance,  the  albumoses  are  partly  precipitated  in  neutral  solutions,  but 
on  the  addition  of  acid  saturated  with  the  salt  they  completely  precipitate. 
This  precipitate,  which  dissolves  on  warming,  is  a  combination  of  albnmose 
with  the  acid. 

"We  formerly  designated  as  peptone  those  proteid  bodies  which  are  readily 
soluble  in  water  and  which  do  not  coagulate  by  heat,  whose  solutions  are 
precipitated  neither  by  nitric  acid,  nor  by  acetic  acid  and  potassium  ferro- 
cyanide, nor  by  neutral  salts  and  acid. 

The  reactions  and  properties  which  the  albumoses  and  peptones  had  in 
common  were  formerly  considered  as  the  following:  They  give  all  the  color 
reactions  of  the  proteids,  but  with  the  biuret  test  they  give  a  more  beautiful 
red  color  than  the  ordinary  proteids.  They  are  precipitated  by  ammoniacal 
lead  acetate,  by  mercuric  chloride,  tannic,  phospho-tungstic,  phospho- 
molybdic  acids,  potassium-mercuric  iodide  and  hydrochloric  acid,  and  lastly 
by  picric  acid.  They  are  precipitated  but  not  coagulated  by  alcohol, 
namely,  the  precipitate  obtained  is  soluble  in  water  even  after  being  in 
contact  with  alcohol  for  a  long  time.  The  albumoses  and  peptones  alsa 
have  a  greater  diffusive  power  than  native  albuminous  bodies,  and  the 
diffusive  power  is  greater  the  nearer  the  questionable  substance  stands  to 
the  final  product,  the  now  so-called  jiure  peptone. 

These  old  views  have  undergone  an  essential  change  in  the  last  few 
years.  After  IIeynsius'  '  observation  that  ammonium  sulphate  was  a 
general  precipitant  for  proteids,  also  peptone  in  the  old  sense,  Kuiine"  and 

•  P  Auger's  Archiv,  Bd.  34. 

2  See  Kilbnc,  Verliandl.  d.  naturhistor.  Vereins  zu  Heidelberg  (N.  F.),  3 ;  J.  Wenz, 
Zeitschr.  f.  Biologie,  Bd.  23  ;  KUlme  and  Cbitteuden,  Zeitschr.  f.  Biologie,  Bd.  23;  R. 
Neumeister,  ibid.,  Bd.  23  ;  Kiihue,  ibid.,  Bd.  29. 


ALBU MOSES  AND  PEPTONES.  35 

his  pupils  proposed  this  salt  as  a  means  of  separating  albumoses  and 
peptones.  Those  products  of  digestion  which  separate  on  saturating  their 
solution  with  ammonium  sulpliate  are  considered  by  KCuxe  and  indeed  by 
most  of  the  modern  investigators  as  albumoses,  while  those  which  remain 
in  solution  are  called  peptones  or  pure  peptone.  This  pure  peptone  is 
formed  in  relatively  large  amounts  in  pancreatic  digestion,  while  in  pepsin 
digestion  it  is  only  formed  in  small  quantities  or  after  prolonged  digestion. 

According  to  Schutzexbeugeu  and  Kuhxk'  the  proteids  yield  two 
chief  groups  of  new  albuminous  bodifes  Avhen  decomposed  by  dilute  mineral 
acids  or  with  proteolytic  enzymes;  of  these  the  anti  group  shows  a  greater 
resistance  to  further  action  of  the  acid  and  enzyme  than  the  other,  namely, 
the  hcmi  group.  These  two  groups  are,  according  to  Kuiixe,  united  in 
the  dilferent  albumoses,  even  though  in  various  relative  amounts,  and  each 
albumose  contains  the  anti  as  Avell  as  the  hemi  group.  The  same  is  true  for 
the  peptone  obtained  in  pepsin  digestion,  hence  he  calls  it  amplioi^eptone. 
In  tryptic  digestion  a  cleavage  of  the  amphopeptone  takes  place  into  anti- 
peptone  and  liemii)eptone.  Of  these  two  peptones  the  hemipeptone  is  further 
split  into  amido  acids  and  other  bodies  while  the  antipeptone  is  not 
attacked.  By  the  sufficiently  energetic  action  of  trypsin  only  one  peptone 
is  at  last  obtained,  the  so-called  antipeptone.  According  to  the  researches 
of  Kutscher'  the  antipeptone  obtained  in  the  pancreatic  digestion  is  not 
a  chemical  individuality,  but  a  mixture  in  which  the  hexon  bases  histidin 
and  arginin,  besides  monamido  acids,  have  been  detected.  This  also  follows 
from  the  observations  made  by  Balke  that  the  antipeptone  prepared  by 
him  could  be  separated  into  two  parts  by  phospho-tungstic  acid,  one  part 
rich  in  bases  and  the  other  rich  in  acids.  For  these  reasons  Kutscher  also 
denies  the  chemical  individuality  of  carnic  acid  (see  page  4o),  which 
Siegfried  and  Balke  consider  as  identical  with  antipeptone.  "With  this 
view  the  work  of  Balke  is  hard  to  reconcile,  as  this  investigator  has 
prepared  several  metallic  salts  of  antipeptone  which  corresponds  to  Sieg- 
fried's formula  for  carnic  acid.  As  we  are  not  Justified  in  doubting  the 
reliability  of  either  investigator  we  can  possibly  seek  the  contradictory 
statements  in  the  manner  of  procedure  of  the  two  investigators.  Balke 
allowed  the  digestion  to  go  on  for  only  four  days,  while  Kutscher,  on  the 
contrary,  allowed  it  to  continue  for  forty  days;  and  as  Kutscuer,  in  a  sub- 
sequent work,'  has  shown  that  by  sufficiently  energetic  and  continuous  trypsin 
digestion  the  antipeptone  (the  substance  which  gives  the  biuret  reaction)  is 
completely  decomposed  or  exists  only  as  traces,  it  is  possible  that  Kutscher 

'  SclilitZLMiberger,  Bull,  de  la  soc.  chimique  de  Paris,  23  ;  Kuhue,  Yeihandl.  d. 
naturhist.  Vereius  zu  Heidelberg  (N.  F),  Bd.  1;  and  Klihiic  aud  Chittenden,  Zeitscbr. 
f.  Biologie.  Bd.  19.     See  also  Paal,  Ber.  d.  deutscb.  cbem.  Gesellscb.,  Bd.  27. 

«  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  25,  S.  195,  aud  Bd.  26,  S.  110. 

*  Die  Endprodukte  der  Trypsiuverdauuug,  Habilitationsscbiift,  Strassburg,  1899. 


36  THE  PROTEIN  SUBSTANCES. 

in  his  lengthy  digestion  experiments  split  the  chief  part  of  Balke's  anti- 
peptone.  This  qiTestion  requires  further  elucidation.  On  account  of 
obserrations  given  in  the  previous  memoir  Kutscher  is  of  the  opinion  that 
at  least  in  the  proteids  of  the  pancreas  gland  the  occurrence  of  an  anti 
group  may  be  excluded.  He  also,  for  other  reasons,  differs  from  the 
common  view  of  Kuhne,  in  regard  to  the  digestive  cleavage  of  proteids. 
According  to  him  it  would  be  simplest  and  best  to  return  to  the  old  nomen- 
clature and  call  the  primary  albumoses  propeptone  and  the  deuteroalbnmoses 
and  Kuhne's  j^eptone,  on  the  contrary,  peptone. 

KuHNE  and  his  joupils,  who  have  conducted  these  complete  investiga- 
tions on  the  albumoses  and  peptones,  classify  the  various  albumoses  accord- 
ing to  their  different  solubilities  and  precipitation  powers.  In  the  pepsin 
digestion  of  fibrin'  they  obtained  the  following  albumoses :  {a)  Hetero- 
albnmose,  insoluble  in  water  but  soluble  in  dilute  salt  solution;  (5) 
Fj-otalbumose,  soluble  in  salt  solution  and  water.  These  two  albumoses  are 
precipitated  by  ISTaCl  in  neutral  solutions,  but  not  completely.  Hetero- 
albumose  may,  by  being  in  contact  with  water  for  a  long  time  or  by  drying, 
be  converted  into  a  modification,  called  (c)  Dysalhumose,  which  is  insoluble 
in  dpiite  salt  solutions,  [d)  Deuieroalhumose  is  an  albumose  which  is 
soluble  is  water  and  dilute  salt  solution  and  which  is  incompletely  precipi- 
tated from  acid  solution  by  saturating  with  NaCl  and  not  precipitated  from 
neutral  solutions.  This  precipitate  is  a  combination  of  the  albumose  with 
acid  (Herth°).  The  he teroalbumose  is  essentially  the  same,  as  described 
by  Brucke,  as  peptone. 

The  albumoses  obtained  from  different  proteid  bodies  do  not  seem  to  be 

identical,  but  differ  in  their  behavior  to  precipitants.     Special  names  have 

been  given  to  these  various  albumoses  according  to  the    mother-proteid, 

namely,   glohuloses^    viteUoses,    caseoses,    myosinoses,    etc.      These    various 

albumoses  are  further  distinguished,  a,s  proto-,  hereto-,  and  deutero -caseoses 

for  example.     All  the  albumoses  formed  in  the  digestion  of  animal  and 

vegetable  proteid  are  embraced  in  the  common  name  proteoses  by  Chitten- 

DEX.^     Certain   proteoses  have  also  been  obtained   in  a  crystalline  state 

(Sciirotter). 

Neumeister*  designates  as  atmidalbumose  that  body  which  is  obtained  by  the  action 
of  siiperlieated  steam  on  fibrin.  At  the  same  time  he  also  obtained  a  substance  called 
atmidalbuvdii,  Avhich  stands  between  the  albuminates  and  the  albumoses. 

*  See  Kuhne  and  Chittenden,  Zeitschr.  f.  Biologic,  Bd.  20. 
'  Monatshefte  f.  Chem.,  Bd.  5. 

2  Kiihne  and  Chittenden,  Zeitschr.  f.  Biologic,  Bdd.  22  and  25  ;  Neumelster,  ibid., 
Bd.  23;  Chittenden  and  Ilartwell,  Journ.  of  Phy,siol.,  Vols.  11  and  12  ;  Chittenden  and 
Painter,  Studies  from  the  Laboratory,  etc.,  Yale  University,  Vol.  2,  New  Haven,  1891  ; 
Chittenden,  iWrf.,  Vol.  3;  Sebelien,  Chem.  Ceutralblatt,  1890;  Chittenden  and  Good- 
win, Journ.  of  Physiol.,  Vol.  12. 

*  Zeitschr.  f.  Biologic.  Bd.  26.  See  also  Chittenden  and  Meara,  Jourii,  of  Physiol., 
Vol.  15,  and  Salkowski,  Zeitschr.  f.  Biologic,  Bd.  34. 


ALBUMOSES  AND  PEPTONES.  37 

Of  the  soloble  albnmoses  Neumeister  designates  protoalbumose  and 
heteroalbumose  as  j)n'7>iarij  albnmoses,  while  the  denteroalbnmoses,  wliich 
are  closely  allied  to  the  pej)tones,  he  calls  secondary  albionoscs.  As  essen- 
tial dilTerence  between  the  primary  and  secondary  albumoses  he  suggests  the 
following: '  Tlfe  primary  albumoses  are  precipitated  by  nitric  acid  in  salt- 
free  solutions,  wliile  the  secondary  albumoses  are  only  precipitated  in  salt 
solutions,  and  certain  deuteroalbumoses,  such  as  deuterovitellose  and  den- 
teromyosinose,  are  only  precipitated  by  nitric  acid  in  solutions  saturated 
with  NaCl.  The  primary  albumoses  are  preci2)itated  from  neutral  solutions 
by  copper  sulphate  solution  (2  :  100),  also  by  XaCl  in  substance,  while  the 
secondary  albnmoses  are  not.  The  primary  albumoses  are  completely  pre- 
cipitated from  tlieir  solution  saturated  with  XaCl  by  the  addition  of  acetic 
acid  saturated  with  salt,  while  the  secondary  albumoses  are  only  partly 
precipitated.  The  primary  albumoses  are  readily  precipitated  by  acetic 
acid  and  i)otassium  ferrocyanide,  while  the  secondary  are  only  incomjiletely 
precipitated  after  some  time.  The  primary  albumoses  are  also,  according 
to  Pick,"  completely  precijiitated  by  ammonium  sulphate  (add  to  one  half 
saturation),  while  the  secondary  albumoses  remain  in  solution. 

The  true  peptones  are  exceedingly  hygroscopic,  and  when  perfectly  dry 
sizzle  like  phosphoric  anhydride  when  treated  with  water.  They  are 
exceedingly  soluble  in  water,  diffuse  more  readily  than  the  albumoses,  and 
are  not  precipitated  by  ammonium  sulphate.  In  contradistinction  to  the 
albnmoses  the  true  peptones  are  not  precipitated  by  nitric  acid  (even  in 
solution  saturated  with  salt),  by  acetic  acid  saturated  with  salt  and  sodium 
chloride,  potassium  ferrocyanide  and  acetic  acid,  picric  acid,  trichloracetic 
acid,  mercuric-potassium  iodide  and  hydrochloric  acid.  They  arc  precipi- 
tated by  phospho-tungstic  acid,  phospho-molybdic  acid,  corrosive  sublimate 
(in  the  absence  of  neutral  salts),  absolute  alcohol  and  tannic  acid,  but  the 
precipitate  may  redissolve  on  the  addition  of  an  excess  of  the  precipitant. 
As  important  difference  between  ampho-peptone  and  antipeptone  we  must 
also  mention  that  the  first  gives  Millox's  reaction  while  the  antipeptone 
does  not. 

Ill  regard  to  the  precipitation  by  alcohol  we  must  call  attention  to  the  observations  of 
Fkankel  that  not  only  are  the  acid  coinbinaiious  of  peptone  (Paal)  soluble  in  alcohol, 
biU  abo  the  free  peptone,  and  Frankel  has  even  suggested  a  method  of  preparation 
based  on  this  behavior.  ScniioTTER*  has  also  prepared  crystalline  albumoses  which 
were  soluble  in  hot  alcohol,  especially  methyl  alcohol. 

According  to  the  ordinary  view  the  albnmoses  are  intermediary  steps  in 
the  formation  of  peptone,  and  indeed  that  from  the  primary  albumoses  the 
deuteroalbumose  is  derived  and  from  thi*s  then  the  peptone.     In  opposition 

'  Neumelster,  Zeitschr.  f.  Biologie,  Bdd.  24,  26. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  24. 

'  Frilnkel,  Zur  Keuntnisse  der  Zerfallsprodukte  des  Eiweisses  bci  peptischer  und 
tryptischer  Verdauung.     Wien,  1896  ;— SchrOtter,  Monatshefte  f.  Chem.,  Bdd.  14,  16. 


38  TEE  PROTEIN  SUBSTANCES. 

to  this  view  it  seems  remarkable  that,  as  found  by  Kuhne/  tlie  deutero- 
fibrinoses  diffnse  less  readily  than  the  protofibrinoses,  and  also,  according  to 
Sabanejew,  the  denteroalbumoses  have  a  higher  molecular  weight  (3200) 
than  the  protalbumoses  (2467-2643).  The  peptones  have  a  lower  molecular 
weight,  as  shown  by  Sabanejew,  Paal,  Sjoqvist,^  to  lie  between  400  and 
250  for  various  preparations,  Schrottee  found  the  molecular  weight  of 
his  albumoses  to  be  600-700.  According  to  Paal  the  acid-combining 
power  of  the  hydration  products  produced  in  peptonization  increases  as  the 
molecular  weight  decreases.  Cohkheim  '  found  this  statement  true,  as  he 
discovered  that  the  antipeptone  had  a  much  higher  hydrochloric  acid-com- 
bining power  than  the  albumoses.  He  also  found  that  the  heteroalbumose 
united  with  a  much  greater  quantity  of  acid  than  the  deuteroalbumose. 

ScHROTTER'*  objects  to  the  above  view  as  to  the  albumoses  being  intermediary  steps 
in  the  formation  of  peptone,  inasmuch  as,  according  to  him,  no  albumoses  are  first  formed 
by  tlie  action  of  acids  on  proteids  which  then  yield  peptone,  but  the  proteid  is  simul- 
taneously split  into  albumoses  and  peptones. 

As  above  stated,  we  consider  the  behavior  to  ammonium  sulphate  as  the 
absolute  difference  between  albumoses  and  peptones.  It  is  still  doubtful 
whethei"  the  behavior  of  a  single  salt,  the  ammonium  sulphate,  yields  suffi- 
<;ient  basis  for  the  characterization  of  two  groups  of  albuminous  bodies,  the 
albumoses  and  peptones;  and  this  question  is  warranted  since,  according  to 
^eumetster,  we  have  a  deuteroalbumose  (formed  from  the  protalbumose  in 
peptic  digestion)  which  is  not  comjjletely  precipitated  by  ammonium 
sulphate.  It  seems  that  the  transformation  of  proteids  into  peptones  takes 
place  through  a  number  of  intermediate  steps  similar  to  the  trans- 
formation of  starch  into  sugar  through  a  series  of  dextrins,  and  as 
ammonium  sulphate  is  not  a  means  of  separation  between  dextrins  and 
sugar,  although  it  precipitates  certain  dextrins,  but  not  all,  so  also  it  is  a 
question  whether  it  can  serve  as  a  means  of  separation  for  the  albumoses 
.and  peptones.  A  complete  separation  of  these  several  intermediate  products, 
as  well  as  their  purification,  is  such  an  extremely  difficult  task  that  it  is 
nearly  impossible  at  present  to  say  how  far  such  a  differentiation  is 
warranted  or  feasible. 

In  recent  times  other  points  of  difference  between  the  peptones  and  albumoses  has  been 
sought  for,  and  SciiKOTTEUaiul  Frankei.  ^  consider  the  sulphur  as  buch.  Sciiuotter  des- 
ignates the  following  as  the  difference  between  albumoses  and  peptones.  The  albumoses 
<;ontain  more  nitrogen  and  have  a  higiier  moiefular  weight  and  contain  sulpiiur.  Ac- 
cording to  Fra'nkel  the  peptones  are  always  free  from  sulphur.  The  albumoses,  on  the 
•contrary,  contain  sulphur,  and  lie  has  only  found  one  aibumose  (in  Kuhne's  sense)  which 
cdid  not  contain  sulphur. 

'  Zeitsclir.  f.  Biologic,  Bd.  29. 

'  Sabanejew,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  26;  Paal,  ibid.,  Bd.  27;  Sjo- 
.qvist,  Skand.  Arch.  f.  Physiol.,  Bd.  5. 

*  Paal,  1.  c. ;  Cohnheim,  Zeitschr.  f.  Biologie,  Bd.  33. 

*  Monatshefte  f.  Chem.,  Bd.  16. 
»  Schrijtter,  1.  c. ;  Frankel,  1.  c. 


ALB U MOSES  AND  PEPTONES.  39 

The  question  as  to  the  difference  between  albnmoses  and  peptones 
has  lately  taken  another  phase,  as  it  is  a  question  whether  the  so-called 
pure  peptones  are  true  proteids  or  not.  According  to  the  researches  of 
Siegfried  and  his  pupils,'  antipeptone  is  identical  with  carnic  acid  (see 
page  43).  If  this  is  true,  then  antipeptone  is  a  monobasic  acid  with  the 
formula  C,„Il,jN,0, ,  having  a  still  smaller  molecular  weight  than  the 
protaniins,  which  can  hardly  be  considered  as  proteid.  Under  such  circum- 
stances it  seems  perhaps  best  to  drop  the  name  antipeptone  if  we  continue 
to  designate  such  bodies  pejitones,  which  are  still  true  proteids  (in  ordinary 
sense).  In  the  sufficiently  energetic  trypsin  digestion  no  peptone  at  all 
is  produced  only  simpler  cleavage  products,  and  the  so-called  amphopeptone 
formed  in  pepsin  digestion  is  the  only  one  which  remains,  the  careful  study 
of  which  will  be  of  the  greatest  interest. 

Lawrow'^  has  recently  published  his  investigations  on  the  peptic  and 
tryptic  digestive  products.  These  observations  show  that  the  products  not 
precipitated  by  ammonium  sulphate  are  not  true  proteids,  but  consist  of  a 
mixture  of  decomposition  products  of  true  proteids.  The  action  of  various 
albumoses  and  peptones,  as  also  antialbumid,  as  well  as  gelatoses  and  gelatin 
peptone,  upon  the  blood-pressure,  blood-coagulation,  etc.,  has  been  studied 
by  Chittenden  '  and  his  pupils,  and  in  connection  with  this  work  they  also 
^Ive  a  few  chemical  investigations  as  to  the  questionable  bodies.  An 
antipeptone  which  was  prepared  from  pure  antialbumid  by  trypsin  digestion 
contained  on  an  average  C  50.93;  N  13,58;  and  S  1.62^.  The  low  per- 
centage of  nitrogen  indicates  that  the  body  was  not  contaminated  by  basic 
substances,  or  only  to  an  insignificant  extent.  On  cleavage  by  boiling  with 
20^  hydrochloric  acid  and  then  determining  the  total  nitrogen,  the 
ammonia  nitrogen,  and  tlie  basic  nitrogen  contained  in  the  phospho-tungstic 
acid  precipitate,  they  found  that  the  basic  nitrogen  amounted  to  17.2^  of 
the  total  nitrogen  of  antialbumid,  27.9,^  of  the  hemialbumose,  and  20.7^  of 
the  hemipeptone. 

What  relationship  do  the  albumoses  and  peptones  bear  to  the  proteid 
from  which  they  are  formed?  The  numerous  analyses  of  different  albumoses 
made  thus  far  show  chiefly  that,  with  the  exception  of  those  albumoses 
which  stand  closest  to  the  true  peptones,  there  is  no  essential  difference 
between  the  composition  of  the  original  proteids  and  the  corresponding 
albumoses.  The  pure  peptones,  as  well  as  certain  albumoses  standing  close 
to  the  pure  peptones,  seem,  on  the  contrary,  to  contain  about  the  same 
amount  of  hydrogen  and  nitrogen  and  to  be  habitually  poorer  in  carbon  than 
the  primary  albumoses  or  the  proteid.* 

'  See  foot-note  on  carnic  acid,  foot-note  2,  page  43 

»  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  26. 

'  Amer.  Journ.  of  Physiol.,  Vol.  2. 

*  Elementary  analyses  of  albumoses  and  peptones  will   be  found  in  the  works  of 


40  THE  PROTEIN  SUBSTANCES. 

The  elementary  analyses  made  up  to  the  present  time  have  not  given  ns 
a  positive  answer  in  regard  to  the  relationship  existing  between  the  proteids 
on  one  side  and  the  albnmoses  and  peptones  on  the  other.  The  view  that 
the  peptone  formation  is  a  hydrolytic  splitting  is  accepted  by  Hoppe- 
Seyler,  Kuhxe,  HenninCtEK,  and  indeed  by  nearly  all  recent  investi- 
gators. In  support  of  this  view  we  have  the  observations  of  Henninger 
and  Hofmeister/  according  to  which  peptones  (the  albnmoses)  are  con- 
verted into  a  proteid  similar  to  albuminates  by  the  action  of  acetic  acid 
anhydride,  or  by  heating  so  that  water  is  expelled.  According  to 
ScHROTTER^  the  albumoscs  do  not  yield  a  regenerated  proteid  with  acetic 
anhydride,  but  an  acetyl  defivative  insoluble  in  water.  An  albaminate-like 
proteid  may  undoubtedly  also  be  regained  on  heating,  which  is  in  accord 
with  Neumeister's  observations. 

According  to  other  investigators,  as  Maly,  Herth,  Lokw,  and  others,  tlie  formation 
of  peptone  is  a  depolymerizaiion  of  the  proteid.  A  third  view  is  that  proteids  and 
peptones  are  isomeric  bodies;  while  a  fourth  view  (Gkiessmayer ')  claims  that  the  pro- 
teids consist  of  micell  groups  which  on  peptonization  are  first  converted  into  micelli  and 
then  further  into  molecules.  Though  an  ordinary  proteid  solution  contains  micelli  or 
micell  bonds,  so  also  a  peptone  solution  contains  proteid  molecules. 

Th^  preparation  of  different  albumoses  in  a  perfectly  pure  form  is  very 
troubWsome  and  accompanied  with  a  great  many  difficulties.  For  this 
reason  there  will  be  given  here  only  the  general  methods  by  which  the 
different  albumose  precipitates  are  obtained.  If  we  proceed  from  a  solution 
of  fibrin  in  pepsin  hydrochloric  acid,  we  first  remove  the  syntonin  or  some 
coagulable  proteid  present  by  first  neutralizing  and  then  coagulating  by 
heat.  The  neutral  filtrate  is  saturated  with  jSTaCl,  which  precipitates  a 
mixture  of  primary  albumoses.  This  precipitate  is  washed  with  a  saturated 
NaCl  solution,  pressed  and  dissolved  in  dilute  salt  solution.  An  insoluble 
residue  remains,  which  is  called  dysalbumose.  The  solution  of  the  primary 
albumoses  is  repeatedly  and  completely  dialyzed.  Heteroalbumose  separates 
out,  while  the  protalbumose  remains  in  solution  and  may  be  precipitated  by 
alcohol.  Tlie  above  filtrate,  which  has  had  the  primary  albumoses  removed 
and  saturated  Avith  NaCl,  is  treated  with  acetic  acid,  which  has  previously 
been  saturated  with  NaCl,  until  no  further  precipitate  occurs.  This  pre- 
cipitate, which  consists  of  a  mixture  of  primary  and  secondary  albumoses,  is 
filtered  off,  the  filtrate  freed  from  salt  by  dialysis,  and  the  deuteroalbu- 
mose  precipitated  by  ammonium  ^mlphate.  The  various  albumoses  may 
also  be  precipitated  from  the  original  solution  by  ammonium  sulphate, 
dissolved  in  Avater  and  freed  from  ammonium  sulphate  by  means  of  dialysis, 
and  then  separated  as  above  described. 

Kliline  and  Chittenden,  cited  in  foot-note,  page  36;  also  by  Ilerth,  Zeitschr.  f.  physiol. 
Cbcm.,  Bd.  1,  and  Monatshefte  f.  Chem.,  Bd.  5;  Maly,  Ptluger's  Arch.,  Bdd.  9,  13. 
Ilenninger,  Compt.  rend.,  Tome  86  ;  Scbrotter,  1.  c;  Paal,  1.  c. 

'  Hoppe-Seyler,  Physiol.  Chem.,  Berlin,  1881  ;  Klihue,  1.  c. ;  Henninger,  1.  c. ;  Ilof- 
meister,  Zeitsclir.  f.  physiol.  Chem.,  Bd.  2. 

'  Monatshefte  f.  Chem.,  Bd.  17. 

'  Maly,  1.  c;  Herth,  1,  c;  Loew,  Pfluger's  Arch.,  Bd.  31 ;  Griessmayer,  see  Maly's 
Jabresb..  Bd.  14,  S.  26. 


SEPARATION  OF  CLEAVAGE  PRODUCTS.  41 

In  the  separation  of  primary  albnmoses  from  the  secondary,  as  well  as  in 
the  separation  of  the  dilTerent  deuteroalbumoses,  we  can  make  use  of  frac- 
tional precipitation  with  ainmonium  sulphate  as  suggested  by  Pick,  Umijer  ' 
has  investigated  the  proteid-like  cleavage  products  obtained  on  the  pepsin 
digestion  of  ovalLnmin,  seralbumin,  and  serglobulin  by  Pick's  method. 
F,  Alexander'  has  done  the  same  for  casein.  The  usefulness  of  this 
method  has  been  established,  and  though  certain  dilTerences  of  the  various 
proteids  appear,  still  we  always  obtain  an  equal  number  of  cleavage  products, 
which  may  be  separated  by  fractional  precipitation  with  ammonium 
sulphate.  The  first  fraction  contains  the  primary  albumoses,  the  second, 
third,  and  fourth  fractions  the  various  deuteroalbumoses,  and  the  fifth  and 
sixth  two  different  jieptones.  Casein  gave  only  very  little  lieteroalbumose 
and  then  a  peptone.  S,  Fkankel,'  in  the  preparation  of  pure  deutero- 
albumoses, first  removes  the  primary  albumoses  by  precipitation  with  copper 
sulphate.  ^ICller^  separates  the  albumoses  from  the  j^eptones  by  the 
addition  of  an  equal  volume  of  a  30^  ferric  chloride  solution  and  the 
addition  of  alkali  until  the  reaction  is  only  faintly  acid.  The  filtrate  from 
the  voluminous  precipitate  is  treated  with  zinc  carbonate  and  filtered  after 
thorough  stirring.  The  filtrate  is  generally  free  from  albumoses.  Only  in 
solutions  of  AVitte's  peptone  was  it  necessary  to  concentrate  the  filtrate  to 
4~i  its  volume  and  adding  a  little  more  ferric  chloride  and  zinc  carbonate 
to  free  the  solution  from  remaining  traces  of  albumoses. 

In  the  preparation  of  true  peptone  we  make  use  of  a  prolonged  pepsin 
digestion,  but  much  quicker  results  are  obtained  by  the  use  of  trypsin 
digestion.  The  albumoses  must  be  entirely  removed,  which  is  done  by 
alternately  precipitating  in  acid,  neutral  and  alkaline  solution,  witli 
ammonium  sulphate.  According  to  Kuhxe  "  we  proceed  in  the  following 
way:  The  sufficiently  dilute  and  neutral  solution  (free  from  albuminates 
and  coagulable  proteids)  is  first  precipitated,  while  boiling  hot,  with 
ammonium  sulphate.  On  cooling  the  precijiitated  albumoses  and  crystal- 
lized salt  are  removed  by  filtration  and  the  filtrate  heated  to  boiling,  made 
strongly  alkaline  with  ammonia  and  ammonium  carbonate,  again  saturated 
with  ammonium  sulphate  at  tiie  boiling  temperature.  Remove  precipitate 
by  filtration  when  cold,  heat  the  filtrate  again  until  all  odor  of  ammonia  is 
expelled,  saturate  with  ammonium  sulphate  while  hot,  and  acidify  with 
acetic  acid  and  filter  on  cooling. 

The  filtrate  is  freed  from  a  great  part  of  the  salt  by  strongly  concentrate 
ing  the  liquid,  allowing  it  to  cool,  and  removing  the  salt  by  filtration. 
Another  large  portion  of  the  salt  may  be  removed  from  this  filtrate  by  the 
careful  fractional  precipitation  with  alcohol,  which  yields  an  alcoholic  solu- 

■•  Zeitsclir.  f.  pbysiol.  Chcni.,  Bd.  25. 

^  Jbitl,  Bd.  25,  S.  411. 

3  Pick,  1.  c;  Friinkel.  Monatslieftc  f.  Clieru.,  Bd.  18. 

•»  Zeitscbr.  f.  physiol.  Chem..  Bd.  26. 

'  Zeitschr.  f.  Biologic,  Bd.  29. 


42  TUE  PROTEIN  SUBSTANCES. 

tion  rich  in  peptone  with  only  a  small  quantity  of  ammonium  salt.  This 
solution  is  boiled  to  remove  the  alcohol,  and  then  boiled  with  barium  car- 
bonate to  remove  the  ammonium  sulphate.  The  filtrate  is  freed  from 
excess  of  barium  by  the  careful  addition  of  dilute  sulphuric  acid.  This 
filtrate,  which  must  not  contain  an  excess  of  sulphuric  acid,  is  now  concen- 
trated and  the  peptone  precipitated  therefrom  by  alcohol. 

Frankel  has  suggested  another  method  which  is  dependent  upon  the  solubility  of 
the  peptones  in  alcohol.  Baumann  and  Bomer  '  precipitate  the  albumoses  by  zinc 
sulphate. 

For  the  detection  of  albumoses  and  peptones  in  animal  fluids  we  proceed 
as  follows,  according  to  Devoto  :  The  coagulable  proteids  are  removed  by 
prolonged  heating,  the  solution  saturated  with  ammonium  sulphate.  True 
peptones  (besides  deuteroalbumose  not  precipitated)  may  be  detected  in  the 
cold  filtrate  by  means  of  the  biuret  test.  The  remaining  albumoses  are 
contained  in  the  mixture  of  precipitate  and  salt  crystals  collected  on  the 
filter.  The  albumoses  are  dissolved  from  this  mixture  by  washing  with 
water,  and  may  be  detected  in  the  wash-water  by  means  of  the  biuret  test. 
According  to  Halliburton  and  Colls"  traces  of  albumoses  may  be 
formed  in  this  method  by  the  prolonged  heating.  As  the  best  method  they 
suggest  either  the  precipitation  of  the  native  proteids  by  the  addition  of 
IQfo  trichloracetic  acid  solution  or  making  the  native  proteids  insolnble  by 
the  )^ntinuous  action  of  alcohol.  The  last  method  is  not  quite  applicable 
to  blood-serum,  as  the  so-called  fibrin-ferment,  which  also  gives  the  biuret 
test,  is  not  made  insolnble  by  this  procedure. 

If  a  solation  saturated  with  ammonium  sulphate  is  to  be  tested  by  the 
biuret  test,  it  must  first  be  treated  with  a  slight  excess  of  concentrated 
caustic-soda  solution,  keeping  the  solation  cold,  and  after  the  sodium 
sulphate  has  settled  the  liquid  is  treated  with  a  2^  solution  of  copper 
sulphate,  drop  by  drop. 

The  biuret  test  (colorimetric)  and  the  polariscopic  method  have  been 
used  in  the  quantitative  estimation  of  albumoses  and  peptones.  These 
methods  do  not  yield  exact  results. 

Coagulated  Proteids.  Proteids  may  be  converted  into  the  coagulated 
condition  by  different  means:  by  heating  (see  page  25),  by  the  action  of 
alcohol,  especially  in  the  presence  of  neutral  salts,  by  prolonged  shaking 
their  solutions  (Ramsdex'),  and  in  certain  cases,  as  in  the  conversion  of 
fibrinogen  into  fibrin  (Chapter  VI),  by  the  action  of  an  enzyme.  The 
nature  of  the  processes  which  take  place  during  coagulation  is  unknown. 
The  coagulated  albuminous  bodies  are  insoluble  in  water,  in  neutral  salt 
solutions,  and  in  dilute  acids  or  alkalies,  at  normal  temperature.  They  are 
dissolved  and  converted  into  albuminates  by  the  action  of  less  dilute  acids 
or  alkalies,  especially  on  heating. 

Coagulated  proteids  seem  also  to  occur  in  animal  tissues.     We  find,  at 

'  Frilnkel,  1.  c,  Zur  Kenntniss,  etc.;  Bomer,  Cliem.  Centralbl.  1898,  1,  S.  640. 
«  Devoto,  Zeitschr.  f.  physiol.  Clieni.,  Bd.  15  ;  Halliburton  and  Colls,  Journ.  of  Path. 
andBact.,  1895. 

'  Du  Bois-Reymoud's  Arch.,  1894. 


VEGETABLE  AND  POISONOUS  PR0TETD8.  43 

least  in  many  organs  such  as  the  liver  and  other  glands,  proteids  wliich  are 
not  soluble  in  water,  dilute  salt  solutions,  or  very  dilute  alkalies,  and  only 
dissolve  after  being  modified  by  strong  alkalies. 

Appendix. 

Vegetable  Proteids.  A'egetable  proteids  seem  to  have  the  same  essential 
properlieri  as  the  animal  proteids,  and  the  three  chief  groups  of  native 
proteids  occur  in  the  plants  as  well  as  the  animal  organism.  We  recognize 
the  following  as  vegetable  proteids:  albumi)is^  glohulins  (phytovitellin, 
vegetable  myosin,  paraglobulin),  and  micleoalbmnitis  (pea-legumin).  Be- 
sides these  a  special  group  of  coagulated  proteids,  so-called  gluten  proteins, 
occur,  which  are  partly  soluble  in  alcohol.  It  seems  that  too  much  im- 
portance is  given  to  the  solubilities  of  the  vegetable  proteids,  and  more 
exhaustive  investigations  seem  to  be  necessary.' 

Poisonous  Proteids.  Attention  was  called  in  the  first  chapter  to  the  fact 
that  high  i)lants  and  animals,  as  well  as  microbes,  can  produce  proteids 
having  specific,  sometimes  intense,  poisonous  action. 

We  know  very  little  positively  in  regard  to  the  nature  of  these  proteids. 
Those  which  have  been  isolated  belong  to  certain  of  the  proteid  groups — 
some  are  albumins,  others  globulins  or  compound  proteids,  and  the  majority 
seem  to  be  albumoses — still  little  is  known  in  regard  to  their  chemical 
nature.  From  a  chemical  standpoint  we  do  not  differentiate  between  a 
poisonous  and  a  harmless  proteid;  for  example,  between  a  poisonous  and  a 
non-poisonous  globulin.  The  fundamental  question  whether  those  that 
have  been  isolated  as  poisonous  proteids  are  really  poisonous  or  not,  oi 
whether  they  consist  of  a  harmless  proteid  contaminated  with  a  polsonou? 
substance,  cannot  be  considered  as  settled. 

Carnic  acid,  which  is  considered  as  identical  with  antipeptone,  stands  h 
close  relationship  to  the  so-called  true  peptones. 

Carnic  Acid.  This  acid,  discovered  by  Siegfried,  was  first  obtaineLi  tvs 
a  c  eivage  product  of  phospho-carnic  acid  occurring  in  muscles  (see  Chapter 
XI).  Carnic  acid  is  produced  from  the  proteid,  according  to  Siegfried, 
under  the  same  conditions  as  antipeptone,  with  which  Balke'  considers  it 
identical  (see  page  35).  It  is  a  monobasic  acid  with  the  formula 
CjgHijNgOj.  It  is  split  into  lysin,  lysatin,  and  ammonia  by  15^  hydro- 
chloric acid  at  130°  C,  which  seems  remarkable  when  we  consider  the  low 
molecular  weight  of  the  acid  and   the    presence  of  only  three  atoms   of 

'  See  Kjeldabl  :  Undersogelser  over  de  optiske  Forhold  lios  nogle  PlanteiCggelivide- 
stoffer.  Forhaudlingcr  vqd  de  skaudinaviske  Xalurfoiskeies  14.  M5de.  KjObcn- 
bavn,  1892. 

'  Siegfried,  Du  Bois-Reymond's  Arch.,  1894,  and  Zeitschr.  f.  pbysiol.  Cbem.,  Bd. 
21  ;  Balke,  ibid.,  Bd.  22. 


44  THE  PROTEIN  SUBSTANCES. 

nitrogen  in  the  molecule.  On  the  oxidation  of  the  barium  salt  by  barium 
permanganate  oxycarnic  acid,  with  the  formula,  Cg^H^jNgOjj ,  is  obtained, 
which  is  derived  from  three  molecules  of  carnic  acid  with  the  elimination 
of  four  atoms  of  hydrogen. 

Carnic  acid  is  an  extremely  hygroscopic  substance,  being  very  sol  able  in 
water.  It  also  dissolves  in  hot  alcohol  and  separates  out  as  undefined 
crystalline  plates  on  cooling.  It  gives  with  hydrochloric  acid  an  additional 
product  with  the  formula  Cj^Hj^lSTjOj-HCl,  and  also  yields  salts  with  several 
metals.  Among  the  salts  the  silver  salt  with  42.G;o  silver  is  of  special 
importance.  This  acid  acts  like  antipeptone  towards  most  precipitants  and, 
like  this,  is  not  precipitated  by  ammonium  sulphate. 

Tbe  methods  of  preparing  caruic  acid  from  proteids  are  the  same  as  tlie  methods  of 
preparing  pure  untipeptones  in  tryptic  digestion.  According  to  Siegfried  carnic  acid  is 
obtained  from  meat  extract  iu  the  following  way:  The  extract  free  from  proteids  is  com- 
l)lftely  precipitated  with  calcium  chloride  and  ammonia.  The  phosphocarnic  acid  is 
precipitated  from  ihe  filtrate  as  au  iron  combination,  carniferrin,  bj^  ferric  chloride.  This 
carniferrin  is  decomposed  at  50°  by  barium  hydrate,  filtered,  the  excess  of  barium  re- 
moved from  the  filtrate  by  sulphuric  acid,  filtered,  concentrated  and  precipitated  with 
alcohol.     The  acid  is  purified  by  repeated  resolution  and  precipitation  with  alcohol. 

/  II.  Com  pound  Proteitls. 

With  this  name  77e  designate  a  class  of  bodies  which  are  more  complex 
than  the  simj^le  proteids  and  which  yield  as  nearest  splitting  products 
simple  proteids  on  one  side  and  non-proteid  bodies,  such  as  coloring  matters, 
carbohydrates,  xanthin  bodies,  etc.,  on  the  other.' 

The  compound  proteids  known  at  the  present  time  are  divided  into 
three  chief  groups.  These  groups  are  the  hcmnoglohins,  the  glycoproteids, 
and  the  nndeojyroteids.  The  hsemoglobins  Avill  be  treated  of  in  a  following 
chapter  (Chapter  YI),  on  the  blood. 

Glycoproteids  are  those  compound  proteids  which  on  decomposition 
yield  a  proteid  on  one  side  and  a  carbohydrate  or  derivatives  of  the  same  on 
the  other,  but  no  xanthin  bodies.  Some  glycoproteids  are  free  from  phos- 
phorus (mucin  substances,  chondroproteids,  and  hyalogens),  and  some 
contain  phosphorus  (phosphoglycoproteids). 

Mucin  Substances.  We  designate  as  mucins  colloid  substances  whose 
solutions  are  mucilaginous  and  thready,  and  wliich  when  treated  with  acetic 
axjid  give  a  precipitate  insoluble  in  an  excess  of  acid,  and  on  boiling  with 
dilute  mineral  acids  yield  a  substance  capable  of  reducing  copper  oxyhydrate. 
This  last-mentioned  fact,  which  was  first  observed  by  EicinvALD,°  differen- 
tiates mucins  from  other  bodies  which  have  long  been  mistaken  for  it  and 
which  have  similar  physical  properties.     On  the  other  hand,  bodies  whose 


'  Hoppe-Seyler  lias  given  tlie  name  proie'ide  to  these  compound  proteids,  but  as  this 
term  is  misleading  in  Engli.sh  we  do  not  use  it  iu  English  classifications  in  this  sense, 
'  Annal.  d.  Chem.  u.  Pharni.,  Bd.  134. 


MUCINS.  45 

pliysical  properties  dilTer  from  it,  but  wliich  give  a  reducible  substance  on 
boiling  with  dilute  mineral  acids,  liave  also  l)een  designated  as  mucins. 

The  ditTerent  bodies  characterized  as  mucin  substances  correspond,  first, 
either  to  true  vmcins,  or,  second,  to  mucoids  or  mucifwidSy  or  third  to 
vhondruprufcids. 

All  mucin  substances  contain  carbon,  hydrogen,  nitrogen,  sulphur,  and 
v.rggen.  Compared  with  albuminous  bodies  they  contain  less  nitrogen  and, 
as  a  rule,  considerably  less  carbon.  As  immediate  decomposition  products 
they  yield  albuminous  bodies  on  one  side  and  carboliydrates  or  acids  allied 
thereto  on  the  other.  On  boiling  with  dilute  mineral  acids  they  all  give  a 
reducing  substance. 

The  true  mucins  are  characterized  by  their  natural  solution,  or  one 
prepared  by  the  aid  of  a  trace  of  alkali,  being  mucilaginous,  thread-like, 
and  giving  a  precipitate  with  acetic  acid  which  is  insoluble  in  excess  of  acid. 
The  mucoids  do  not  show  these  physical  properties  and  have  other  solubili- 
ties and  precipitation  properties.  As  we  have  intermediate  steps  between 
different  albuminous  bodies,  so  also  we  have  such  between  true  mucins  and 
mucoids,  and  a  sharp  line  between  these  two  groups  cannot  be  drawn. 

True  mucins  are  secreted  by  the  larger  mucous  glands,  by  certain 
mucous  membranes,  also  by  the  skin  of  snails  and  other  animals.  True 
mucin  also  occurs  in  the  connective  tissue  and  navel-cord.  Sometimes,  as 
in  snails  and  in  the  membrane  of  the  frog-egg  (Giacosa  '),  a  mother- 
substance  of  mucin,  a  mucinogen,  has  been  found  which  may  be  converted 
into  mucin  by  alkalies.  Mucoid  substances  are  found  in  cartilage,  certain 
cysts,  in  the  cornea,  the  crystalline  lens,  white  of  egg,  and  in  certain  ascitic 
fluids.  As  the  mucin  question  has  been  very  little  studied,  it  is  at  the 
present  time  impossible  to  give  any  positive  statements  in  regard  to  the 
occurrence  of  mucins  and  mucoids,  especially  as  without  doubt  in  many 
cases  non-mucinous  substances  have  been  described  as  mucins.  So  mucli  is 
sure,  that  mucins  or  nearly  related  bodies  occur  widely  diffused  in  the 
organism  in  certain  tissues.  From  their  decomposition  products  we  derive 
a  great  deal  of  knowledge  in  regard  to  the  formation  and  cleavage  of  carbo- 
hydrates or  kindred  l)odies  (glycuronic  acid)  from  other  complex  groups. 

True  Mucins.  Thus  far  we  have  been  able  to  obtain  only  a  few  mucins 
in  a  pure  and  nnclianged  condition  due  to  the  reagents  used.  The  elemen- 
tary analyses  of  these  mucins  have  given  the  following  results: 

C            H            N  S            O 

Mucin  from  snail   50.32  6.84  i:3.65  1.75  27.44  (Hammarsten) 

Mucin  from  tendon 48.30  6.44  11.75  0.81  32.70  (Loebisch) 

Mucin  from  submaxillary.   ..  48.84  6.80  12.32  0.84  31.20  (Hammaksten) 

The  mucin  of  the  snail-skin,  which  stands  closest  to  keratin,  contains 
more  sulphur  than  the  other  mucins.     The  same  is  true  for  the  mucin 

'  ZeitscUr.  f.  pbysiol.  Chem.,  Bd.  7  ;  also  Hammarsteu,  Pflliger's  Arcbiv,  Bd.  36- 


46  TEE  PROTEIN  SUBSTANCES. 

obtained  from  the  Achilles  tendon  of  oxen  as  prepared  by  Chittenden  and 
GiEs/  which  contains  on  an  average  2.33^  snlphar.  The  sulphur  is,  at 
least  in  certain  mucins,  partly  split  oif  by  alkali,  and  in  others  not. 

By  the  action  of  superheated  steam  on  mucin  a  carbohydrate,  animal 
gnm  (Landwehk),  is  split  off.  This  has  not  been  substantiated  by  other 
investigators  such  as  Folin  and  F.  Muller.'''  Instead  of  a  non-nitrogenous 
gum  a  nitrogenous  carbohydrate  was  obtained. 

On  boiling  mucin  with  dilute  mineral  acids,  acid  albuminate  and  bodies 
similar  to  albumose  or  peptone  are  obtained,  besides  a  reducing  substance. 
MuLLER  obtained  25-32^  reducing  substance  on  boiling  the  mucus  from 
the  respiratory  organs  with  "di  sulphuric  acid.  He  also  prepared  a  crystal- 
line phenylhydrazine  combination  therefrom  having  a  melting-point  of 
198°  C.  and  differing  in  other  regards  from  glucosazon.  He  considers  it 
as  an  osazon  of  a  hexose  which  he  calls  imicose.  Muller  could  not  prepare 
the  sugar  itself,  but  obtained  a  crystalline  substance  containing  6.4^  N  and 
considered  as  mucosamin.  Jazewitz  ^  could  not  obtain  any  sugar  from 
mucin  but  an  osazon  melting  at  185°  C.  and  a  mucosamin.  Muller^  by 
a  different  and  better  method  has  obtained  a  benzoyl  combination,  and  then 
frorn  this  a  crystalline  hydrochloric  acid  combination  of  its  mucosamin,  by 
boiling  mucin  with  acids.  The  crystallographic  researches,  as  well  as  the 
determination  of  its  optical  rotation,  show  so  much  to  the  identity  of  this 
combination  with  chitasamin  hydrochloride  that  Muller  considers  the 
name  mucosamin  unnecessary.  The  osazon  obtained  from  this  combination 
differs,  on  the  contrary,  from  the  glucosazon  in  the  following:  It  melts  at 
192  to  196°,  it  is  readily  soluble  in  alcohol,  and  is  la3vo-rotatory.  According 
to  E.  Fischer,  who  has  investigated  it,  it  is  not  identical  with  glucosazon, 
but  seems  rather  to  be  galactosazon.  On  boiling  mucins  with  hydrochloric 
acid  acetic  acid  may  also  be  sjilit  off,  and  indeed  ^-1  molecule  for  each 
molecule  of  reducing  substance.  By  the  action  of  stronger  acids  we  obtain 
among  other  bodies  leucin,  tyrosin,  and  levulinic  acid.  Certain  mucins,  as 
the  submaxillary  mucin,  are  easily  changed  by  very  dilute  alkalies,  as  lime- 
water,  while  others,  such  as  tendon-mucin,  are  not  affected.  If  a  strong 
caustic-alkali  solution,  as  a  bfo  KOH  solution,  is  allowed  to  act  on  submaxil- 
lary mucin,  we  obtain  alkali  albuminate,  bodies  similar  to  albumose  and 
peptone,  and  one  or  more  substances  of  an  acid  reaction  and  with  strong 
reducing  powers. 

'  Hammarsteii,  Pfliiger's  Arch.,  Bd.  36,  aiul  Zeitschr.  f.  ph3'siol,  Chem.,  Bd.  12  ; 
Loebisch,  ibid.,  Bd.  10,  and  Chittenden  and  Gies,  Journ.  of  Expt.  Med.,  Vol.  1. 

»  Landvvelir,  Zeitschr.  f.  physiol.  Chem.,  Bdd.  8,  9  ;  also  Pfluger's  Arch.,  Bdd.  39 
and  40  ;  Folin,  Zeitschr.  f.  physiol.  Chem.,  T.d.  28;  Fr.  Miiller,  Sitzungsber.  d.  Gesell- 
Bch.  zur  BefOrd.  d.  gcsamnit.  Naturwiss.  zu  Marburg,  1896. 

»  Mailer,  1.  c;  Jazewitz,  Arch.  d.  scien.  bid.  do  St.  Petersbourg,  Tome  5. 

*  Sitzungsber.  zur  BefOrd.  d.  gesammt.  Naturwiss.  zu  Marburg,  1898. 


MUCOTDS.  47 

In  one  or  the  other  respect  the  dillerent  mneins  act  somewhat  differently. 
For  examj)le,  the  siuiil  and  tendon  mucins  are  insoluble  in  dilute  liydro- 
chloric  acid  of  \-l  p.  m.,  while  the  mucin  of  the  submaxillary  gland  and 
the  navel-cord  are  soluble.  Tendon-mucin  becomes  llaky  with  acetic  acid, 
while  the  other  mucins  are  precipitated  in  more  or  less  fibrous,  tough 
masses.     Still  all  the  mucins  have  certain  reactions  in  common. 

In  the  dry  state  mucin  forms  a  white  or  yellowish-gray  powder.  When 
moist  it  forms,  on  tlie  contrary,  ilakes  or  yellowish-white  tough  lumps  or 
masses.  The  mucins  are  acid  in  reaction.  They  give  the  color  reactions  of 
the  albuminous  bodies.  They  are  not  soluble  in  water,  but  may  give  a 
neutral  solution  with  water  and  the  smallest  quantity  of  alkali.  Such  a 
solution  does  not  coagulate  on  boiling,  while  acetic  acid  gives  at  the  normal 
temperature  a  precipitate  which  is  insoluble  in  an  excess  of  the  precipitant. 
If  5-10^  XaCl  be  added  to  a  mucin  solution,  this  can  now  be  carefully 
acidified  with  acetic  acid  without  giving  a  precipitate.  Such  acidified  solu- 
tions are  copiously  precijiitated  by  tannic  acid;  Avith  potassium  ferrocyanide 
they  give  no  precipitate,  but  on  sufiicient  concentration  they  become  thick 
or  viscous.  A  neutral  solution  of  mucin-alkuli  is  precipitated  by  alcohol 
in  the  presence  of  neutral  salts;  it  is  also  precipitated  by  several  metallic 
salts.  If  mucin  is  heated  on  the  water-bath  with  dilute  liydrochloric  acid 
of  about  2^,  the  liquid  gradually  becomes  a  yellowish  or  dark  brown  and 
reduces  copper  oxyhydrate  from  alkaline  solutions. 

The  mucin  most  readily  obtained  in  large  quantities  is  the  submaxillary 
mucin,  which  maybe  prepared  in  the  following  way:  The  filtered  watery 
extract  of  the  gland,  free  from  form-elements  and  as  colorless  as  possible,  is 
treated  with  25^  hydrochloric  acid,  so  that  the  liquid  contains  1.5  p.  m, 
HCl.  On  the  addition  of  the  acid  the  mucin  is  immediately  precipitated, 
but  dissolves  on  stirring.  If  this  acid  liquid  is  immediately  diluted  with 
2-3  vols,  of  water,  the  mucin  separates  and  may  be  purified  by  redissolving 
in  1-5  p.  m.  acid,  and  diluting  with  water  and  washing  therewith.  The 
mucin  of  the  navel-cord  may  be  prepared  in  the  same  way.^  The  tendon- 
mucin  is  prepared  from  tendons  which  have  first  been  freed  from  proteid 
by  common-salt  solution  and  water.  They  are  extracted  with  one  half 
saturated  lime-water,  the  filtrate  is  precipitated  with  acetic  acid,  and  the 
precipitate  purified  by  redissolving  in  dilute  alkali  or  lime-water,  precipitat- 
ing with  acid,  and  washing  with  water  (Rollett,  Loebisch,  Chittenden", 
and  GiEs).'     Lastly,  the  mucins  are  treated  with  alcohol  and  ether. 

Mucoids  or  Mucinoids.  In  this  group  we  must  include  those  non- 
phosphorized  glycoproteids  which  are  neither  true  mucins  nor  chondro- 
proteids  even  though  they  show  amongst  themselves  such  a  difference  in 
behavior  that  they  can  be  divided  into  several  sub-groups  of  mucinoids. 
To  the  mucinoids  belong  pseudoimicin,  the  probably  related  body  colloid, 

'  The  author  has  not  been  able  to  obtaiu  this  pure,  so  the  aiialyis  is  uot  given  in 
the  previous  table  of  the  mucins. 

»  Rollett,  Wieu.  Sitzungsber.,  Bd.  39,  Abth.  2  ;  Loebisch,  Chittenden  and  Gies,  1.  c. 


48  TEE  PROTEIN  SUBSTANCES. 

ovomucoid^  and  other  bodies,  which  on  account  of  their  differences  will  be 

best  treated  of  individually  in  their  respective  chapters. 

Hyalogens.  Under  this  name  Khukenberg'  Las  designated  a  number  of  differing 
bodie's,  wiiicb  are  characterized  by  the  following  :  By  the  action  of  alkalies  they  change, 
with  the  splitting  off  of  sulphur  and  some  nitrogen,  into  soluble  nitrogenized  products 
called  by  him  hyalines  and  which  yield  a  pure  carbohydrate  by  further  decomposition. 
We  lind  that  very  heterogeneous  substances  are  included  in  these  groups.  Certain 
of  these  hyalogens  seem  undoubtedly  to  be  glycoproteids.  Neossin  ■  of  the  Chinese 
edible  swallow's-nest,  membranin  ^  of  Debcemet's  membrane  and  of  the  capsule 
of  the  cr3^stalline  lens,  and  spirogra'pldn  *  of  the  skeletal  tissue  of  the  worm  Spirographis 
seem  to  act  as  such.  Others  on  the  contrary,  such  as  hyalin  ^  of  the  walls  of  hydatid 
cysts,  oniipldn^  from  the  tubes  of  Ouuphis  tubicola,  seem  not  to  be  compound  proteids. 
The  so-called  mucin  of  the  holoihures,'^  and  chondrosin^  of  the  sponge,  Chondrosia  reui- 
formis.  and  others  may  also  be  classed  Avith  the  hyalogens.  As  the  various  bodies  desig- 
nated by  KiiUKENBERG  as  hyalogens  are  very  dissimilar,  it  is  not  of  much  importance  to 
arrange  these  in  special  groups. 

Chondroproteids  are  such  glycoproteids  which  as  closest  cleavage 
products  yield  proteid  and  an  ethereal  sulphuric  acid  containing  carbo- 
hydrate, cliondroitin-sulphuric  acid.  Chondromucoid,  occurring  in  cartilage 
is  the  best  example  of  this  group.  Amyloid  occurring  under  pathological 
conditions  also  belongs  to  this  group.  On  account  of  the  property  of 
chondroitin-sulphuric  acid  of  precipitating  proteid  it  is  also  possible  that 
under  certain  circumstances  combinations  of  this  acid  with  proteid  may  be 
precipitated  from  the  urine  and  be  considered  as  chondroproteids. 

Chondromucoid  has  greatest  interest  as  a  constituent  of  cartilage,  and  on 
this  account  this  body  and  also  its  cleavage  product,  chondroitin-sulphuric 
acid,  will  be  treated  of  in  connection  with  cartilage  (Chapter  X).  On  the 
contrary,  amyloid,  which  has  always  been  treated  of  in  connection  with  the 
protein  substances,  will  be  described  here. 

Amyloid,  so  called  by  Vmcuow,  is  a  protein  substance  appearing  under 
pathological  conditions  in  the  internal  organs,  such  as  the  spleen,  liver,  and 
kidneys,  as  infiltrations;  and  in  serous  membranes  as  granules  with  con- 
centric layers.  It  probably  also  occurs  as  a  constituent  of  certain  prostate 
calculi.  The  chondroproteid  occurring  under  physiological  conditions  in 
the  walls  of  the  arteries  is  perhaps,  according  to  Krawkow,  very  nearly 
related  to  the  amyloid  substance  even  if  not  identical. 

Amyloid  was  first  prepared  pure  recently  by  Krawkow. °     The  sub- 

'  Verb.  d.  physik. -med.  Gesellsch.  zu  Wiirzburg,  1883  ;  also  Zeitschr.  f.  Biologic, 
Bd.  22. 

2  Krukenberg,  Zeitschr.  f.  Biologic,  Bd.  22. 

2  C.  'Ih.  Morner,  Zeitschr.  f.  i)liysiol.  Chem.,  Bd.  18. 

*  Krukenberg,  Wiirzburg,  Verhandl.  1883  ;  also  Zeitschr.  f.  Biologic,  Bd.  22. 

'  A.  Lllcke,  Virchow's  Arch.,  Bd.  19  ;  also  Krukenberg,  Vergleichende  physiol. 
Stud.,  Series  1  and  2,  1881. 

«  Schmiedeberg,  Milth.  aus  d.  zool.  Stat,  zu  Neapel,  Bd.  3,  1882. 
'  Hilger,  Pili'iger's  Archiv,  Bd.  3. 

*  Krukenberg,  Zeitschr.  f.  Biologie,  Bd.  22. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  40,  which  also  contains  the  older  literature. 


AMYLOID  AND  PnOSPHOOLYCOPJiOTEIDS.  49 

stance  prepared  by  liim  contained  C  4:8.80-50.38;  II  (J. 0.5-7. 02;  N  13.79- 
l-i.07;  and  S  2.G5-2.89f^.  Phosphorus  does  not  occur  in  the  pure  sub- 
stance. It  splits,  by  the  iiction  of  alkali,  into  proteid  and  chondroitin- 
sulphuric  acid  (see  Chapter  X)  and  according  to  Krawkow  is  therefore 
perhaps  an  ester-like  combination  of  this  acid  with  proteid. 

Amyloid  is  an  amorphous  white  substance,  insoluble  in  water,  alcohol, 
ether,  dilute  hydrochloric  and  acetic  acids.  It  is  soluble  in  concentrated 
hydrochloric  acid  or  caustic  alkali  with  decomposition.  On  boiling  with 
dilute  hydrochloric  acid  it  yields  sulphuric  acid  and  a  reducing  substance. 
It  is  not  dissolved  by  gastric  juice.  It  is  nevertheless  changed  so  that  it  is 
soluble  in  dilute  ammonia,  while  the  genuine  typical  amyloid  is  insoluble 
therein.  Amyloid  gives  the  xanthoproteic  reaction  and  the  reactions  of 
MiLLOX  and  Auamkiewicz.  Its  most  important  property  is  its  behavior 
with  certain  coloring  matters.  It  is  colored  reddish  brown  or  a  dingy 
violet  by  iodine;  a  violet  or  blue  by  iodine  and  sulphuric  acid;  red  by 
methylaniline  iodide,  especially  on  the  addition  of  acetic  acid;  and  red  by 
aniline  green.  Of  these  color  reactions  those  with  aniline  dves  are  the  most 
important.  The  iodine  reaction  appears  less  constant  and  is  greatly 
dependent  upon  the  physical  condition  of  the  amyloid.  The  color  reactions 
are  dependent  upon  the  presence  of  the  chondroitin-sulphnric  acid  com- 
ponent. 

The  preparation  of  amyloid  may  be  performed  as  follows  according  to 
Kraavkow:  The  finely  divided  mass  of  organ  is  exhausted  first  with  water 
and  then  with  dilute  ammonia,  Avhich  leaves  the  insoluble  amyloid  and 
removes  the  free  or  the  combined  chondroitin-sulphnric  acid  besides  other 
substances.  The  product,  after  being  washed  Avith  water,  is  digested  with 
pepsin  for  several  days  at  38°  C.  The  residue,  after  washing  with  hydro- 
chloric acid  and  water,  is  dissolved  in  dilute  ammonia,  filtered,  again 
precipitated  with  dilute  hydrochloric  acid,  dissolved,  if  necessary,  in 
ammonia,  precipitated  a  second  time  with  hydrochloric  acid,  washed  with 
water,  the  precipitate  dissolved  in  baryta-water,  which  leaves  the  nucleius 
undissolved,  and  the  barium  filtrate  precipitated  with  hydrochloric  acid,  and 
then  washed  with  water,  alcohol,  and  ether. 

Phosphoglycoproteids.  This  group  includes  the  pbosphorized  glycopioteids.  Tbey 
yioM  no  xanthiu  substances  (nuclein  bases)  as  cleavage  products.  Tbey  :ire  not  nucleo- 
l)roteids  and  tberefore  Ibey  must  not  be  considered  togetber  witb  the  glycouuclcopro- 
teids  (uucleoglycoprolelds)  or  mistaken  for  tbem.  On  pepsin  digestion  tbey  may  like 
certain  uucleoalbumins  yield  pseudonuclein,  but  tbey  dilTer  from  tbe  nucleoalljumins 
in  tbat  tbey  yield  a  reducing  substance  on  boiling  witb  dilute  acid.  Tbey  differ  from 
tbe  glycouucleoproteids  in  tbat  tbey  do  not,  as  above  mentioned,  yield  any  xantbin 
bodies. 

Only  two  pbospborized  glycoproteids  are  known  at  tbe  present  time,  namely,  ich- 
thulin,  occurring  in  carp  eggs  and  studied  by  Waltek  '  and  wbich  was  considered  as  a 
vitelliu  for  a  time.  Icbthulin  has  tbe  following  composition  :  C  53.52;  H  7.71 ;  N  15.64; 
S  0.41 ;  P  0.43;  F^  0A0%.  In  regard  to  solubilities  it  is  similar  to  a  globulin.  Walter 
has  prepared  a  reducing  substance  from  tbe  parauucleiu  of  icbthulin  which  gave  a  very 
crystalline  combination  with  pbenylbydrazin. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  15. 


50  THE  PROTEIN  SUBSTANCES. 

Another  phosphoglycoproteid  is  litlicoproteid,  obtaiued  by  the  author'  from  the 
glauds  of  the  snail  Helix  pomatia.  It  has  the  following  composition:  C  46.99;  H6.78; 
N  6.U8  ;  S  0.62  ;  P  0.47/o.  It  is  converted  into  a  gummy,  Isevo-rotatory  carbohydrate, 
called  animal  sinistrin,  by  the  action  of  alkalies.  On  boiling  with  an  acid  it  yields  a 
dextro-rotatory,  reducing  substance. 

Nucleoproteids.  With  this  name  we  designate  those  compound  proteids 
which  yield  trne  nncleins  (see  Chapter  V)  on  j)epsin  digestion  and  those 
which  yield,  besides  proteids,  xanthin  bodies  or  so-called  naclein  bases 
(parin  bases)  on  boiling  with  dilate  mineral  acids. 

The  nucleoproteids  seem  to  be  widely  diffused  in  the  animal  body. 
They  occur  chiefly  in  the  cell-nuclei,  but  they  also  often  occur  in  the  proto- 
plasm. They  may  pass  into  the  animal  fluids  on  the  destruction  of  the 
cells,  hence  nucleoproteids  have  also  been  found  in  blood-serum  and  other 
fluids. 

They  may  be  considered  as  combinations  of  a  proteid  nucleus  with  a  side 
chain,  which  Kossel  calls  the  prostetic  group.  This  side  chain,  which 
contains  the  phosphorus,  may  be  split  off  as  nucleic  acid  (see  Chapter  Y)  on 
treatment  with  alkali.  As  we  have  several  nucleic  acids,  it  follows  that  we 
must/ have  different  nucleoproteids,  depending  upon  the  nucleic  acid  united 
with  the  proteid.  Certain  nucleic  acids  contain  a  readily  sj)lit  off'  sugar 
(pentose  or  hexose),  others  on  the  contrary  not.  In  the  first  case  we 
obtain  from  the  corresponding  nucleoproteid  a  reducing  sugar  on  boiling 
with  dilute  mineral  acid,  while  in  the  other  case  this  is  not  possible.  This 
different  behavior  may  be  accounted  for  by  a  special  group  of  nucleoproteids, 
the  glyconucleoproteids  or  nucleoglycoproteids.  Such  glyconucleoproteids 
occur  in  yeast-cells,  in  the  pancreas,  and,  as  it  ajipears,  are  widely  dis- 
tributed in  the  animal  organism. 

The  native  nucleoproteids  contain  a  variable  but  not  a  high  percentage 
of  phosphorus,  which  Halliburton'  found  to  vary  between  0.5^  and 
1.6^.  On  heating  their  solutions,  as  well  as  by  the  action  of  dilute  acids, 
a  modification  of  the  compound  proteid  takes  place  and  nucleoproteids  of 
strong  acid  character,  poorer  in  proteid  but  richer  in  phosphorus,  are 
formed.  The  native  nucleoproteids  have  faint  acid  properties  and  are  in- 
soluble in  water  but  whose  alkali  combinations  soluble  in  water  split  on 
heating  their  solution  into  coagulated  proteid  and  a  nucleoproteid  rich  in 
phosphorus,  which  remains  in  solution.  In  peptic  digestion  they  yield  so- 
called  true  nuclein.  The  proteid  can  be  precipitated  by  acetic  acid  from  its 
alkali  coml^ination,  and  the  precipitate  dissolves  Avith  more  or  less  readiness 
in  an  excess  of  the  acid.  A  confusion  may  occur  here  with  nncleoalbumins 
and  also  with  mucin  substances.  This  confusion  may  be  avoided  by  warm- 
ing the  body  for  some  time  on  the  watcr-l)ath  with  dilute  sulphuric  acid, 
nearly  neutralizing  the  boiling-hot  fluid  with  barium  hydrate,  filtering  as. 

'  HammarstcD,  Pfinger's  Arch.,  Bd.  36.  «  Journ.  of  Physiol.,  Vol.  18. 


ALB V MOWS   OR  ALBUMINOIDS.  61 

quick  as  possible  while  boiling  hot,  supersaturating  the  filtrate  with  am- 
monia, and  then  on  cooling  (when  a  precipitate  consisting  of  guanin  is 
filtered  oil  and  specially  tested)  testing  for  xanthin  bodies  by  an  ammoniacal 
silver  nitrate  solntion.  Any  precipitate  formed  is  examined  more  closely  by 
the  method  as  given  in  Chapter  \ .  The  nncleoproteids  give  the  color  reac- 
tions of  the  proteids. 

The  properties  of  the  various  nncleoproteids  are  given  in  detail  in  the 
various  chapters  which  follow. 

III.  Albumoids  or  Albuiiiiiioids. 

Under  this  name  we  collect  into  a  special  group  all  those  protein  bodies 
which  cannot  be  placed  in  either  of  the  other  two  groups,  although  they 
differ  essentially  among  themselves  and  from  a  chemical  standpoint  do  not 
show  any  radical  difference  from  the  true  proteid  bodies.  The  most  im- 
portant and  abundant  of  the  bodies  belonging  to  this  group  are  important 
constituents  of  the  animal  skeleton  or  the  cutaneous  structure.  They  occur 
as  a  rule  in  an  insoluble  state  in  the  organism,  and  they  are  distinguished 
in  most  cases  by  a  pronounced  resistance  to  reagents  which  dissolve  proteids, 
or  to  chemical  reagents  in  general. 

The  Keratin  Group.  Keratin  is  the  chief  constituent  of  the  horny 
structure,  of  the  epidermis,  of  hair,  wool,  of  the  nail,  hoofs,  horns, 
feathers,  of  tortoise-shell,  etc.,  etc.  Keratin  is  also  found  as  neurokeratin 
(Kuhne)  in  the  brain  and  nerves.  The  shell-membrane  of  the  hen's  egg 
seems  also  to  consist  of  keratin,  and  according  to  Neumeister  '  the  organic 
matrix  of  the  egg-shells  of  various  vertebrate  animals  belongs  in  most  cases 
to  the  keratin  group. 

It  seems  that  there  exist  more  than  one  keratin,  and  these  form  a  special 
group  of  bodies.  This  fact,  together  with  the  difficulty  in  isolating  the 
keratin  from  the  tissues  in  a  pure  condition  without  a  partial  decomposi- 
tion, is  sufficient  explanation  for  the  variation  in  the  elementary  composition 
given  below.  As  examples  the  analyses  of  a  few  tissues  rich  in  keratin  and 
of  keratins  are  given  as  follows : ' 

C  H  N  S           O 

Human  hair...  50.65  6.36  17.14  5.00  20.85  (v.  Laar) 

Nail 51.00  6.94  17.51  2.80  21.75  (Mulder) 

Neurokeratin....  56.11-58.45  7.26-8.02  11.46-14.32   1.63-2.24  (Kuhne) 

Horn  (averas^e)..  50.86  6.94              3.30         . . .  (Hohbaczewski) 

Tortoise-shell....  54.89  6.56  16.77  2.22  19.56  (Muldp:k) 

Shell-membrane.  49.78  6.64  16.43  4.25  22.90  (Lindvall) 

'  Kilhne  and  Ewald,  Verh.  d.  naturhistor.-med.  Vereins  zu  Heidelberg  (X.  F.),  Bd. 
1  ;  also  Klihue  and  Chittenden,  Zeitschr.  f.  Biologic,  Bd.  23  ;  Neumeister,  ibid.,  Bd.  31. 

*  V.  Laar,  Anual.  d.  Chem.  u.  Pharm.,  Bd.  45  ; — Mulder,  Versuch  einer  allgem. 
physiol.  Chem.,  Braunschweig,  1844-51;  Kiihne,  Zeitschr.  f.  Biologic,  Bd.  26;  Hor- 
baczewski,  see  Drechsel  in  Ladenburg's  HandwOrterbuch  d.  Chem.,  Bd.  3;  Lindvall, 
Maly's  Jahresbericht,  1S81. 


52  THE  PROTEIN  SUBSTANCES. 

MoHii '  has  determined  the  quantity  of  sulj^hur  in  various  keratin  sub- 
stances. Sulphur  is  at  least  in  part  in  loose  combination,  and  it  is  partly 
removed  by  the  action  of  alkalies  (as  sulphides),  or  indeed  in  part  by  boiling 
with  water.  Combs  of  lead  after  long  usage  become  black,  and  this  is  due 
to  the  action  of  the  sulphur  of  the  hair.  On  heating  keratin  with  water  in 
sealed  tubes  to  a  temperature  of  150°  to  200°  C.  it  dissolves,  with  the 
elimination  of  sulphuretted  hydrogen,  forming  a  non-gelatinizing  liquid 
which  contains  albumose  (called  Iceratinose  by  Krukenberg  ")  and  pep- 
tone (?).  Keratin  is  dissolved  by  alkalies,  especially  on  heating,  forming, 
besides  alkali  sulphides,  albumoses  and  peptones  (?). 

The  dconiposition  products  of  keratins  are  moreover  the  same  as  the  true 
proteids.  On  boiling  with  acids  we  obtain  besides  leucin  and  tyrosin,  which 
occurs  in  relatively  great  amounts  (1-5^),  aspartic  acid^  and  glutamic 
acid,^  ammonia,  and  sulphuretted  hydrogen.  Hedin  "  has  obtained  lysin, 
arginin,  and  a  substance  containing  sulphur,  whose  combination  with  HCl 
has  the  composition  Cj^Hg^X^O^.^SCl^ ,  from  horn  shavings. 

There  is  no  doubt  that  the  keratins  are  derived  from  the  proteids. 
Dre^hsel  °  is  also  of  the  opinion  that  in  the  keratin  a  part  of  the  oxygen 
of  the  proteids  is  exchanged  for  sulphur,  and  a  part  of  the  leucin,  or  any 
other  amido-acid,  is  exchanged  for  tyrosin.  Keratin  and  proteids  give  the 
same  decomposition  products,  with  the  exception  that  the  former  gives 
proportionally  a  greater  quantity  of  tyrosin.  Among  the  sulphurized 
cleavage  products  of  keratin  Emmerlixg  found  cystin,  and  Suter'  thio- 
ladic  acid.     Suter  conld  not  detect  either  cystin  or  cystein. 

Bodies  occur  in  the  animal  kingdom  which  form  intermediate  bodies 
between  coagulated  albumin  and  keratin.  C.  Th.  MoRXERMias  detected 
such  a  body  {alhumoid)  in  the  tracheal  cartilage,  which  forms  a  net-like 
trabecular  tissue.  This  substance  appears  to  be  related  to  the  keratins  on 
account  of  its  solubilities  and  on  the  quantity  of  the  sulpuhur  (which  turns 
lead  black)  it  contains,  while  according  to  its  solubility  in  gastric  juice  it 
must  stand  close  to  the  proteids.  Another  substance,  more  similar  to 
keratin,  forms  the  horny  layer  in  the  gizzard  of  birds.  According  to 
J.  IIedenius"  this  substance  is  insoluble  in  gastric  or  pancreatic  juice  and 

'  Zeitschr.  f.  physiol.  Cbem.,  Bd.  20. 

*  Uutersucli.  liber  d.  cheni.  Ban  d.  Eiweisskorper.  Sitzuugsber.  d.  Jeuaiscbcn 
Gesellsch.  f.  Med.  u.  Naturwissoiiscb.,  188G. 

*  Kreusler,  Journ.  f.  prakt.  Cbeni.,  Bd.  107. 

*  Ilorbaczcwski,  Sitzungsber.  d.  k.  k.  Wieu.  Akad.  d.  Wissensch.,  Bd.  80. 

'>  Kgl.  fysiogr.  Sallsk.  i  Lund  bandlingar,  Bd.  4;  also  Maly's  Jabresber.,  1893,  and 
Zeitschr.  f.  physiol.  Chem.,  Bdd.  20  and  21. 

*  Drecbsel  in  Ladenburg's  Ilandwortcrbucli  d.  Cliem.,  Bd.  3. 

'  Emmcrliug,  Bef.  in  Cbcmiker  Zoitg.,  Mo.  80,  1894  ;  Suter,  Zeitschr. ^f.  physiol, 
Chem..  Bd.  20. 

»  See  Maly's  Jabresber.,  1888. 
»  Skan.  Arcb.  f.  Pbysiol..  Bd.  3. 


ELA8TIN.  53 

acts  (juite  similar  to  keratin.      It  contains  only  I'ji  snlphnr,  and  yields  on 
decomposition  only  very  little  tyrosin  besides  considerable  leucin. 

Keratin  is  amorphous  or  takes  the  form  of  the  tissues  from  which  it  was 
prepared.  On  heating  it  decomposes  and  generates  an  odor  of  burnt  iiorn. 
It  is  insoluble  in  water,  alcoliol,  or  ether.  On  heating  with  water  to 
150°-200°  C.  it  dissolves.  It  also  dissolves  gradually  in  caustic  alkalies, 
especially  on  heating.  It  is  not  dissolved  by  artificial  gastric  juice  or  by 
trypsin  solutions.  Keratin  gives  the  xanthoproteic  reaction,  as  well  as  the 
\eaction  with  Millox's  reagent,  although  not  always  typical. 

In  the  preparation  of  keratin  a  finely  divided  horny  structure  is  treated 
first  with  boiling  water,  then  consecutively  with  diluted  acid,  pepsin-hydro- 
chloric acid,  and  alkaline  trypsin  solution,  and,  lastly,  with  water,  alcohol, 
and  ether. 

Elastin  occurs  in  the  connective  tissue  of  higher  animals,  sometimes  ia 
such  large  fiuantities  that  it  forms  a  special  tissue.  It  occurs  most 
abundantly  in  the  cervical  ligament  (ligamentum  nucha"). 

Elastin  is  generally  considered  as  a  sulphur-free  substance.  According 
to  the  investigations  of  Ciiittexdex  and  Hart,  it  is  a  question  whether  or 
not  elastin  does  not  contain  sulphur,  which  is  removed  by  the  action  of  the 
alkali  in  its  preparation.  II.  ScnwARZ  has  been  able  to  prepare  an  elastin 
containing  sulphur  from  the  aorta  by  another  method,  and  this  sulphur  can 
be  removed  by  the  action  of  alkalies,  without  changing  the  properties  of 
the  elastin,  and  recently  Zoja,  Hedin,  and  Bergh  '  have  found  that  elastin 
contains  sulphur.  The  most  trustworthy  analyses  of  elastin  from  the  cervical 
ligament  (Xos.  1  and  2)  and  from  the  aorta  (N:>.  3)  have  given  the  follow- 
ing results: 

S  O 

....  21.94      (HORBACZEWSKl)'^ 

21.79     (Chittenden  and  Haut) 

0.38         (H.  ScuwAKz) 

Zoja  found  0.270,'^  sulphur  and  16.9G^  nitrogen  in  elastin.  IIedin" 
and  Bergh  found  different  quantities  of  nitrogen  in  elastin,  depending  upon 
whether  Horbaczewski's  or  Sciiavarz's  method  was  used  in  its  prepara- 
tion. In  the  first  case  they  found  15.44f^  nitrogen  and  0.55^  sulphur,  and 
in  the  other  14.07,'^  nitrogen  and  O.GG^^  sulphur. 

The  cleavage  products  of  elastin  are  the  same  as  for  the  true  jiroteids, 
with  the  difference  that  glycocoll  but  no  aspartic  and  glutamic  acids  are 
obtained.'  Tyrosin  is  only  obtained  in  small  quantities.  Schwarz  was 
able  to   detect   lysatin    in    the    decomposition    products,   but   IIedix  and 

'  Cliitteiuleu  and  Ilait,  Zeilschr.  f.  Biologic,  Bd.  25;  Sclnvarz,  Zeilscbr.  f.  pbysiol. 
Cbem.,  Bd.  18  ;  Zoja,  ibid.,  Bd.  23  ;  Bergh,  ibid.,  Bd.  25  ;  Hediu,  ibid. 
'  Horbaczewski,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  6. 
*  See  Drccbscl  in  Ladenburg's  Haudworterbucb,  Bd.  3. 


C 

H 

N 

1. 

54.32 

6.99 

16  75 

2. 

54  24 

7.27 

16.70 

3. 

53.95 

7.03 

16.67 

54  THE  PROTEIN  SUBSTANCES. 

Bergh  could  not  find  either  lysin  (lysatin)  or  arginin.  On  putrefaction  by 
anaerobic  micro-organisms  Zoja  foand  carbon  dioxide,  hydrogen,  methane, 
mercaptan,  butyric  acid,  valerianic  acid,  ammonia,  and  possibly  also 
phenylpropionic  acid  and  aromatic  oxyacids.  Indol  and  skatol  have  not 
been  found  in  putrefaction,'  but  Schwarz,  on  the  contrary,  obtained  indol, 
skatol,  benzol,  and  phenols,  on  fusing  aorta-elastin  with  caustic  potash. 
On  heating  with  water  in  closed  vessels,  on  boiling  with  dilute  acids,  or  by 
the  action  of  proteolytic  enzymes,  the  elastin  dissolves  and  splits  into  two 
chief  products,  called  by  Horbaczewski  hemielastin  and  elastin^jeptone. 
According  to  Chittenden  and  Hart,  these  products  correspond  to  two 
albumoses  designated  by  them  protoelastose  and  deuteroelastose.  The  first 
is  soluble  in  cold  water  and  separates  on  heating,  and  its  solution  is  precipi- 
tated by  mineral  acid  as  well  as  by  acetic  acid  and  potassium  ferrocyanide. 
The  watery  solution  of  the  other  does  not  become  cloudy  on  heating,  and  is 
not  precipitated  by  the  above-mentioned  reagents. 

Pure  dry  elastin  is  a  yellowish-white  powder;  in  the  moist  state  it 
appears  like  yellowish-white  threads  or  membranes.  It  is  insoluble  in 
wate^",  alcohol,  or  ether,  and  shows  a  resistance  against  the  action  of 
chehiical  reagents.  It  is  not  dissolved  by  strong  caustic  alkalies  at  the 
ordinary  temperature,  and  only  slowly  at  the  boiling  temperature.  It  is 
very  slowly  attacked  by  cold  concentrated  sulphuric  acid,  and  it  is  relatively 
easily  dissolved  on  warming  with  strong  nitric  acid.  Elastins  of  differing 
origins  act  differently  with  cold  concentrated  hydrochloric  acid;  for  in- 
stance, elastin  from  the  aorta  dissolves  readily  therein,  while  elastin  from 
the  ligamentum  nuchas,  at  least  from  old  animals,  dissolves  with  difficulty. 
Elastin  is  more  readily  dissolved  by  warm  concentrated  hydrochloric  acid. 
It  responds  to  the  xanthoproteic  reaction  and  with  Millon's  reagent. 

On  account  of  its  great  resistance  to  chemical  reagents,  elastin  may  be 
prepared  (best  from  the  ligamentum  nucha?)  in  the  following  way:  First 
boil  with  water,  then  with  1^  caustic  potash,  then  again  Avith  water,  and 
lastly  with  acetic  acid.  The  residue  is  treated  with  cold  b<fo  hydrochloric 
acid  for  twenty-four  hours,  carefully  washed  with  water,  boiled  again  with 
water,  and  then  treated  with  alcohol  and  ether. 

aSchwarz  first  incompletely  digested  the  tissues  with  pepsin,  washed 
first  with  soda  solution  and  then  with  water,  and  boiled  lastly  with  water 
until  the  elastic  substance  was  dissolved  away.  The  dried  and  powdered 
substance  is  again  digested  witli  gastric  juice  and  treated  as  above,  and  then 
boiled  with  water  until  the  contaminating  reticulin-like  substance  is  com- 
pletely removed. 

Collagen,  or  gelatin-forming  substance,  occurs  very  extensively  in  verte- 
brates.    The  llesh  of  cephalopods  is  claimed  to  contain  collagen.''     Collagen 

'  Walcbli,  Journ.  f.  prakt.  Chem.,  Bd.  17. 

'  iloppeSeyler,  Pbysiol.  Chem.     Beiliu,  1877-81.     S.  97. 


COLLAGEN.  55 

is  the  chief  constituent  of  the  fibrils  of  the  connective  tissue  and  (as  ossein) 
of  the  organic  substances  of  the  bony  structure.  It  also  occurs  in  the 
cartilaginous  tissues  as  chief  constituent,  but  it  is  here  mixed  with  otlier 
substances,  producing  what  was  formerly  called  chondrigen.  Collagen  from 
different  tisues  has  not  f{uite  the  same  composition,  and  probably  there  are 
several  varieties  of  collagen. 

By  continuously  boiling  with  water  (more  easily  in  the  presence  of  a 
little  acid)  collagen  is  converted  into  gelatin.  IIofmeister  '  found  that 
gelatin,  on  being  heated  to  130"  C,  is  again  transformed  into  collagen;  and 
this  last  may  be  considered  as  the  anhydride  of  gelatin.  Collagen  and 
gelatin  have  about  the  same  composition :' 

C  H           X  S-fO 

Collai,^eii 50.75  •     6.47  17.86  24.92  (Hofmeister) 

GoliUiu  (from  hartshorn) 49.31  6.55  18.37  25.77  (Mulder) 

Gelatin  (from  boues) 50.00  6.50  17.50  26.00  (Premy) 

Purilieil  gelatin 50.14  6.69  18.12  (Paal) 

Gelatin  contains  regularly  small  amounts  of  sulphur  which  probably 
belongs  to  the  gelatins  and  does  not  exist  there  as  an  impurity  from  the 
proteids.  Vax  Name  '  has  obtained  a  gelatin  from  connective  tissue,  which 
had  been  digested  with  an  alkaline  pancreas  extract  (2.5  p.  m.  Na^COJ  for 
five  days,  which  contained  on  an  average  0.256,'^  sulphur.  C.  Mokxeh* 
has  prepared  a  typical  gelatin,  with  only  0.2^  sulphur,  by  extracting  com- 
mercial gelatin  for  several  days  with  1-5  p.  m.  caustic  potash. 

Tiie  decomposition  products  of  collagen  are  the  same  as  those  of  gelatin. 
Gelatin  under  similar  conditions  as  the  proteids  yields  amido-acids,  sucli  as 
lencin,  aspartic  and  glutamic  acids,  but  no  tyrosin,  which  is  especially 
important.  It  yields,  on  the  contrary,  large  qitan titles  of  glycocoll,  to 
which  the  name  gelatin  sugar  is  given  on  account  of  its  sweet  taste.  Lysin 
and  lysatin  have  also  been  obtained  from  gelatin  by  Drecrsel  and 
E.  Fischer,  and  arginin  by  IIedijt.  '  On  putrefaction  gelatin  yields 
neither  tyrosin,  indol,  nor  skatol,"  in  which  it  differs  from  the  proteids. 
Still  the  aromatic  group  is  not  absent  in  gelatin,  and  it  acts  like  the 
oxidized  proteid,  the  oxyprotsulphonic  acid,  because  it  yields  benzoic  acid 
(Maly  '). 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 

'  Hofniei.«ter,  1.  c. ;  Mulder,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  45-  Fremy,  Jahresber. 
d.  Chem..  1854;  Paal,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  25. 
^  Jouru.  of  Exp.  Med.,  Vol.  2. 
••  Private  communication  from  Miirner. 

*  See  Drechsel,  Der  Abbau  der  Eiweisskorper.     Du  Bois-Reymond's  Archiv,  1891  ;— 
Hedin,  Zeitschr.  f.  physiol,  Chem.,  Bd.  21. 

*  See  literature  on  the  cleavage  products  of  gelatin  :  Drechsel  in  Ladeaburg's  Hand- 
wOrterbuch,  Bd.  3. 

'  Monatshefte  f.  Chem.,  Bd.  10. 


56  THE  PROTEIN  SUBSTANCES. 

Collagen  is  insolnble  in  water,  salt  solutions,  dilute  acids,  and  alkalies, 
but  it  swells  up  in  dilute  acids.  By  continuons  boiling  with  water  it  is 
converted  into  gelatin.  It  is  dissolved  by  the  gastric  juice  and  also  by  the 
pancreatic  jnice  (trypsin  sohition)  when  it  has  previously  been  treated  with 
acid  or  heated  with  water  above  +  '^0°  C  By  the  action  of  ferrous 
sulphate,  corrosive  sublimate,  or  tannic  acid,  collagen  shrinks  greatly. 
Collagen  treated  by  these  bodies  does  not  putrefy,  and  tannic  acid  is  there- 
fore of  great  importance  in  the  preparation  of  leather. 

Gelatin  or  glutin  is  colorless,  amorphous,  and  transparent  in  thin  layers. 
It  swells  in  cold  water  without  dissolving.  It  dissolves  in  warm  water, 
forming  a  sticky  liquid,  which  solidifies  on  cooling  when  sufficiently  con- 
centrated. The  quantity  of  ash  contained  in  gelatin  is  of  the  greatest 
importance  in  the  gelatinization  of  gelatin  solutions,  as  shown  by  0.  Nasse 
and  A.  Kkuger,"''  namely,  a  diminished  quantity  of  ash  diminishes  the 
gelatinizing  power. 

Gelatin  solutions  are  not  precipitated  on  boiling,  neither  by  mineral 
acids,  acetic  acid,  alum,  lead  acetate,  nor  mineral  salts  in  general.  A 
gelatin  solution  acidified  with  acetic  acid  may  be  precipitated  by  potassium 
ferrocyanide  on  carefully  adding  the  reagent.  Gelatin  solutions  are  precipi- 
tated by  tannic  acid  in  the  presence  of  salt;  by  acetic  acid  and  common 
salt  in  substance;  mercuric  chloride  in  the  presence  of  HCl  and  JSTaCl; 
metaphosphoric  acid,  phosphomolybdic  acid  in  the  presence  of  acid;  and 
lastly  by  alcohol,  especially  when  neutral  salts  are  present.  Gelatin  solu- 
tions do  not  diffuse.  Gelatin  gives  the  biuret  reaction,  but  not  Adamkie- 
"Wicz's.  It  gives  Millon's  reaction  and  the  xanthoproteic  acid  reaction  so 
faintly  that  it  probably  occurs  from  an  impurity  consisting  of  proteids. 
According  to  Morxer,  pure  gelatin  gives  a  beautiful  Milloist's  reaction,  if 
not  too  much  reagent  is  added.  In  the  other  case  no  reaction  or  only  a 
faint  one  is  obtained. 

By  continuous  boiling  with  water  gelatin  is  converted  into  a  non-gelatin- 
izing modification  called  /S-glutin  by  Nasse.  According  to  Nasse  and 
Kruger  the  specific  rotatory  power  is  hereby  reduced  from  —  167.5°  to 
about  —  136°.'  On  prolonged  boiling  with  water,  especially  in  the  presence 
of  dilute  acids,  also  in  the  gastric  or  tryptic  digestion,  the  gelatin  is  trans- 
formed into  gelatin  albumoses,  so-called  gelatoses  and  gelatin  ])epiones.,  which 
diffuse  more  or  less  readily. 

According  to  IIofmeister  two  new  substances,  semigluiin  and  liemi- 
collin,  are  formed.  The  former  is  insolnble  in  alcohol  of  70-80,*^  and  is 
precipitated  by  platinum  chloride.     The  latter,  whicli  is  not  precipitated 

'  Killinc  find  Ewald,  Verb.  d.  imliirhist.  med.  Vcrciiis  in  Heidelberg,  1877,  Hd.  1. 

»  See  Maly's  Jahrcsber.,  Bd.  19. 

*  In  regard  to  the  rotation  of  /J-glutin,  see  Franini,  PUUger's  Arch.,  Bd.  G8. 


RETICULIN.  67 

by  platinum  chloride,  is  soluble  in  alcohol.  Chittenden  and  Solley  ' 
have  obtained  in  the  peptic  and  tryptic  digestion  a  proto-  and  a  deutero- 
gelatose,  besides  some  true  peptone.  The  elementary  composition  of  the 
gelatosea  does  not  essentially  dilTer  from  that  of  the  gelatin.  On  compara- 
tive analyses  of  gelatin,  deuterogelatose  and  gelatin  peptone,  Chittenden* 
and  his  pupils  tind  nearly  the  same  elementary  composition  for  the  gelatin 
and  gelatose,  while  the  gelatin  peptone  was  about  2^  poorer  in  carbon  and 
about  0.6,<^  poorer  in  nitrogen  than  the  gelatin.  Paal'  has  prepared 
gelatin  peptone  hydrochlorides  from  gelatin  by  the  action  of  dilute  hydro- 
chloric acid.  Some  of  these  salts  are  soluble  in  ethyl  and  methyl  alcohol, 
and  others  insoluble  therein.  Tiie  peptones  obtained  from  these  salts 
contain  less  carbon  and  more  hydrogen  than  the  glutin  from  which  they 
originated,  showing  that  hydration  has  taken  place.  Tiie  molecular  weight 
of  the  gelatin  peptone  as  determined  by  Paal  by  IiAOULt's  method  was 
200  to  352,  while  that  for  gelatin  was  878  to  960. 

Collagen  may  be  obtained  from  bones  by  extracting  them  with  hydro- 
chloric acid  (which  dissolves  the  earthy  phosphates)  and  then  carefully 
removing  the  acid  witli  water.  It  may  be  obtained  from  tendons  by 
extracting  with  lime-water  or  dilute  alkali  (which  dissolve  the  proteids  and 
mucin)  and  then  thoroughly  washing  with  water.  Gelatin  is  obtained  by 
boiling  collagen  with  Avater.  The  finest  commercial  gelatin  always  contains 
a  little  proteid,  which  may  be  removed  by  allowing  the  finely  divided 
gelatin  to  swell  up  in  water  and  thoroughly  extracting  with  large  quantities 
of  fresh  water.     Then  dissolve  in  warm  water  and  precipitate  with  alcohol. 

Collagen  may  also  be  purified  from  proteids  as  suggested  by  Van  Xame 
by  digesting  with  an  alkaline  trypsin  solution  or  by  extracting  the  gelatin 
for  days  with  1-5  p.  m.  caustic  potash,  as  suggested  by  Mokner.  The 
typical  properties  of  gelatin  are  not  changed  by  this. 

Chondrin  or  cartilage  gelatin  is  only  a  mixture  of  glutin  with  the  specific  constituents 
of  the  cartilage  and  tlieir  transformation  products. 

Reticulin.  The  reticular  tissues  of  the  lymphatic  glands  contain  a 
variety  of  fibres  which  have  also  been  found  by  Mall  in  the  spleen, 
intestinal  mucosa,  liver,  kidneys,  and  lungs.  These  fibres  consist  of  a 
special  substance,  reticulin,  investigated  by  Siegfried.* 

Reticulin  has  the  following  composition:  C  52.88;  11  6.97;  N  15.63; 
S  1.88;  P  0.3-4;  ash  2.27.  The  phosphorus  occurs  in  organic  combination. 
It  yields  no  tyrosin  on  cleavage  with  hydrochloric  acid.  It  yields,  on  the 
contrar}',   sulphuretted  hydrogen,  ammonia,   lysin,   lysatinin,    and    amido- 

'  Hofmeister,  Zeitschr.  f.  pbysiol.  Cbem.,  Bd.  3;  Chittenden  and  Solley,  Journ.  of 
Physiol.,  Vol.  12. 

*  Amer.  Journ.  of  Physiol.,  Vol.  2. 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  2.3. 

••  Mall,  Abhandl.  d.  math.  phys.  Klasse  d.  Kgl.  sachs.  Gesellsch.  d.  "VViss.,  1891. 
Siegfried,  Ueber  die  chem.  eigenscli.  der  rcticulirten  Gewebe.  Habil-Schrift.  Leipzig, 
1892. 


58 


THE  PROTEIN  SUBSTANCES. 


valerianic  acid.  On  continnons  boiling  with  water,  or  more  readily  witli 
dilate  alkalies,  reticnlin  is  converted  into  a  body  which  is  precipitated  by 
acetic  acid,  and  at  the  same  time  phosphorus  is  split  off. 

Eeticulin  is  insoluble  in  water,  alcohol,  ether,  lime-water,  sodium 
carbonate,  and  dilute  mineral  acids.  It  is  dissolved,  after  several  weeks, 
on  standing  with  caustic  soda  at  the  ordinary  temperature.  Pepsin  hydro- 
chloric acid  or  trypsin  do  not  dissolve  it.  Eeticulin  responds  to  the  biuret, 
xanthoproteic,    and   Adamkiewicz's   reactions,    but    not   with   Millon's 

reagent. 

It  may  be  prepared  as  follows,  according  to  Siegfried:  Digest  intes- 
tinal mucosa  with  trypsin  and  alkali.  Wash  the  residue,  extract  with 
ether,  and  digest  again  with  trypsin  and  then  treat  with  alcohol  and  ether. 
On  careful  boiling  with  water  the  collagen  present  either  as  contamination 
or  as  a  combination  with  reticulin  is  removed.  The  thoroughly  dried 
residue  consists  of  reticulin. 

Ichthylepidin  is  an  organic  substance,  so  called  by  Morner.^  which  occurs  with  col- 
lagen in  tisbscaks  and  form  about  i  of  the  organic  substance  of  the  same.  This 
substance  with  15.9^  nitrogen  and  1.1,^  sulphur  stands  on  account  of  its  properties  rather 
close  to  elastiu.  It  is  insoluble  in  cold  and  hot  water,  as  well  as  in  dilute  acids  and  alka- 
lies at  the  ordinary  temperature.  On  boiling  with  these  it  dissolves.  Pepsin  hydro- 
chlor/c  acid,  as  well  as  an  alkaline  trypsin  solution,  also  dissolve  it.  It  gives  beautiful 
reac^ODS  with  Millon's  reagent,  xanthoproteic  reaction,  and  the  biuret  test.  At  least  a 
part  of  the  sulphur  is  split  ofE  by  the  action  of  alkali. 

Skeletins  are  a   number   of   nitrogenized   substances   which  form  the 

skeletal  tissue  of  various  classes  of  invertebrates  so  designated  by  Keukeis"- 

BERG."     These   substances   are   cJiitin,    spotigin,    conchiolin,    cornein,    and 

fibroin  (silk).     Of  these  chitin  does  not  belong  to  the  proteinsubstances, 

and  fibroin  (silk)  is  hardly  to  be  classed  as  a  skeletin.     Only  those  so-called 

skeletins  will  be  given  that  actually  belong  to  the  protein  group. 

Spongin  forms  the  chief  mass  of  the  ordinary  sponge.  It  gives  no  gelatin.  On  boil- 
ing with  acids,  according  to  the  older  statements  it  yields  leucin  and  glycocoll  and  no 
tyrosin.  Zalocostas  claims  to  have  found  tyrosin  and  also  butalanin  and  glycalanin 
(C5H12N2O4).  After  HuNDESiiAGEN  had  shown  the  occurrence  of  iodine  and  bromine 
in  organic  combination  in  different  sponges  and  designated  the  albumoid  containing 
iodine,  iodospongia,  Hamack^  later  isolated  from  the  ordinary  sponge,  by  cleavage  with 
mineral  acids,  an  iodospongin  which  contained  about  %  iodine  and  4.5^  sulphur. 
Conchiolin  is  found  in  the  shells  of  mussels  and  snails  and  also  in  the  egg-shells  of  these 
animals.  It  yields  leucin  but  no  tyrosin.  The  Byssus  contains  a  substance,  closely 
related  to  conchiolin.  which  is  soluble  with  difficulty.  Cornein  forms  the  axial  system  of 
the  Autipalhes  and  Gorgonia.  It  gives  leucin  and  a  crystallizable  substance,  cornicrys- 
talliii.  According  to  DuECnsEL  ■*  the  axial  system  of  the  gorgonia  cavolini  contain 
nearly  S'/o  of  the  dry  substance  in  iodine.  The  iodine  occurs  in  organic  combination  with 
n  iodized  albumoid,  gorgonin,  Avhich  is  a  cornein.  Drechsel  obtained  leucin,  tyrosin, 
lysin,  ammonia,  and  an  iodized  amido  acid,  iodogorgonic  acid,  which  has  the  composition  of 
a  monoiodo-amido  butyric  acid,  as  cleavage  products  of  gorgouin.  Fibroin  and  Sericin 
are  the  two  chief  constituents  of  raw  silk.  Qy  the  action  of  superheated  water  the  sericin 
dissolves  and  gelatinizes  on  cooling  (silk  gelatin),  while  the  more  difficultly  soluble  fibroin 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  24. 

*  GrundzUge  einer  vergl.  Physiol,  d.  thier.  Geriistsubst.     Heidelberg,  1885. 

»  Zalocostas,  Compt.  rend.,  Tome  107  ;  Hundeshagen,  Maly's  Jahresber.,  1895  ;  Har- 
nack,  Zeitschr.  f.  physiol.  Chem.,  Bd.  24. 

*  Zeitschr.  f.  Biologie,  Bd.  33. 


PROTAMINS.  59 

reTnains  undissolved  in  the  shape  of  the  original  fibre.  On  boiling  witii  acid  tlie  fibroin 
yieids  alaiiin  (Weyl'),  glycoeoli,  and  a  great  deal  of  lyrosin.  Fibroin  is  dissolved  in  odd 
concentraled  liyilrochloric  iii:id  with  Ibf  explusion  of  l,"?  nitrogen  as  ammonia,  aiid  it  is 
converted  into  another,  nearly  related  substance  called  sn-icoin  (Weyl).  Sericin  yields 
no  glycocoil,  but  leucin  and  serin  (amidoethylenlactic  acid).  Tlie  composition  of  the 
jibove-meutioued  Uodies  is  as  follows):' 

C  H  N  S  O 

Conchiolin  (from  snail-eggs)  50  92  6.88  17.86  0.31  24.34  (Kuukenberg) 

Spongin 46.50  6.30  16  20  0.5  27.50  (Ckoockewitt) 

48.75  6.35  16.40  (Pohkelt) 

Cornein 48.96  5.90  16.81  ....  28.33  (Kuukenbekg) 

Fibroin 48.23  6.27  18.31  ....  27.19   (Cka.meh) 

'•       48.30  6.50  19.20  ....  26.00   (Vignon) 

Sericin 44.32  6.18  18.30  ....  30.20  (Cuamer) 

Appendix  to  Chapter  II. 

A.    PROTAMINS   AND   HISTONS. 

Protamins.  In  close  relationship  to  the  proteids  stands  a  group  of  sub- 
stances, the  protamins,  discovered  by  Miescher,  which  are  designated  by 
KossEL  as  the  simplest  proteids  or  as  the  nucleus  of  the  protein  bodies. 
They  correspond  to  the  proteids  in  that  they  give  the  three  basic  bodies, 
lysin,  arginin,  and  histidiu,  on  cleavage  but  differ  from  the  proteids, 
amongst  other  things,  in  not  yielding  any  amido-acids  as  cleavage  products. 
RUPPEL '  has  found  that  the  watery  extract  of  finely  divided  tubercle  bacilli 
when  faintly  alkaline  or  completely  neutral  has  the  property  of  precipitating 
certain  proteids  from  their  solution.  This  property  is  dependent  upon  a 
substance  precipitable  by  acetic  acid  which  he  considers  as  a  combination  of 
a  protamin  tuberculosamin  with  a  nucleic  acid,  tuberculinic  acid.  Free 
nucleic  acid  exists  in  the  watery  extract,  although  the  reaction  is  faintly 
alkaline  or  neutral  (?). 

Protamin  was  discovered  by  Miescuer*  in  salmon  spermatozoa.  Later 
KossEL  isolated  and  studied  similar  bases  from  the  spermatozoa  of  herring 
and  sturgeon.  As  all  these  bases  are  not  identical,  Kossel  uses  the  name 
protamins  to  designate  the  group  and  calls  the  individual  protamins 
sahnin,  chipein,  and  sturin.     Kurajeff  "  has  prepared  a  protamin  from 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  21. 

*  Krukenberg,  Ber.  d.  deutsch.  chem.  Gesellsch.,  .Bdd.  17,  18,  and  Zeitschr.  f. 
Biologic,  Bd.  22  ;  Croockewitt,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  48  ;  Posselt,  ibid.,  Bd. 
45;  Cramer,  Journ.  f.  prakt.  Chem.,  Bd.  96  ;  Viguon,  Compt.  rend.,  115. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

♦  In  regard  to  protamins,  see  Miescher  in  the  histo-chemical  and  physiological  works 
of  Fr.  Miescher,  Leipzig,  1897;  Piccard,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  7; 
Schmiedeberg.  Arch.  f.  e.xp.  Path.  u.  Pharm.,  Bd.  37;  Kossel,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  22  (Ueber  die  basischeu  Stoffe  des  Zellkerns)  and  Bd.  25,  S.  165  and  190, 
and  Sitzungsber.  der  Gesellsch.  zur  Beford.  der  ges.  Naturwiss.  zu  Marburg,  1897  ; 
Kossel  and  Mathews,  Zeitschr.  f.  physiol.  Chem.,  Bdd.  23  and  25. 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 


60  THE  PROTEIN  SUBSTANCES. 

the  spermatozoa  of  mackerel,  which  he  calls  scombrin,  which  stands  close  to 
clnpein  (or  salmin),  but  is  not  identical  therewith.  The  simplest  formula 
for  the  snlphate  is  C,„H.„N,,0,2H,S0,. 

The  protamins  are  substances  rich  in  nitrogen  (30^  N  or  more)  of  a 
basic  nature.  Salmin,  which  is  identical  with  clupein  (Kossel),  has  the 
formula  C,jH,gN,02,  according  to  Mieschee  and  Schmiedeberg,  and 
CjJI^lSr^O, ,  according  to  Kossel.  Sturin  has  probably  the  formula 
CjjHjgNjgO,.  These  statements  of  Kossel  as  to  the  composition  of  clupein 
(or  salmin)  have  been  found  incorrect  by  recent  investigations  of  the  same 
author.  On  heating  with  dilute  mineral  acids,  as  also  by  tryptic  digestion, 
the  protamins  first  yield  protamin  peptone,  protone,  from  which  the  three 
bases,  lysin,  arginin,  and  histidin,  are  derived  on  further  cleavage  (Kossel 
and  Mathews).  A  molecule  of  salmin,  according  to  Kossel,  yields  a 
molecule  each  of  histidin  and  lysin  besides  three  molecules  of  arginin. 
Sturin,  en  the  contrary,  yields  one  molecule  histidin  besides  three  molecules 
arginin  and  tAVO  molecules  lysin.  Neither  lysin  nor  histidin,  but  only 
arginin,  occurs  in  clnpein,  which  is  also  true  for  scombrin.  The  other  con- 
stituents of  the  molecule  of  these  protamins  are  still  unknown.  Kossel 
washable  to  detect  a  body  with  the  composition  of  amido-valerianic  acid  in 
clupein.  We  must  wait  for  further  elucidation  as  to  the  nature  of  the 
protamius  before  we  can  give  anything  positive  as  to  the  relationship  of 
these  bodies  to  the  protein  substances. 

Solutions  of  these  bases  in  water  are  alkaline  and  have  the  property  of 
giving  precipitates  with  ammoniacal  solutions  of  proteids  or  primary 
albumoses.  These  precipitates  are  called  histons  by  Kossel.  The  salts 
with  mineral  acids  are  soluble  in  water,  but  insoluble  in  alcohol  and  ether. 
They  are  more  or  less  readily  precipitated  by  neutral  salts  (NaCl).  Among 
the  salts  of  the  protamins  the  sulphate,  picrate,  and  the  double  platinum 
chloride  are  the  most  important  and  are  used  in  the  preparation  of  the 
protamins.  The  protamins  are  like  the  proteids,  lasvogyrate.  They  give 
the  biuret  test  beautifully,  but  not  Millon's  reaction.  The  protamin  salts 
are  precipitated  in  neutral  or  even  faintly  alkaline  solutions  by  phospho- 
tungstic  acid,  tungstic  acid,  picric  acid,  chromic  acid,  and  alkali  ferro- 
cyanides.  Tlie  two  protamins  salmin  (clupein)  and  sturin  differ  from  each 
other  chiefly  by  a  different  composition,  different  solubilities,  and  somewhat 
different  behavior  of  the  sulphate. 

The  protamins  are  prepared,  according  to  Kossel,  by  extracting  the 
heads  of  the  spermatozoa,  which  have  previously  been  extracted  with 
alcohol  and  ether,  with  dilute  sulphuric  acid  (1-2^),  filtering,  and  precipitat- 
ing with  4  vols,  of  alcohol.  The  sulphate  may  be  purified  by  repeated  solution 
in  water  and  precipitation  with  alcohol,  and  if  necessary  conversion  into  the 
picrate.  Miesciter  extracts  with  very  dilute  hydrochloric  acid,  neutralizes 
the  excess  of  acid,  and  precipitates  the  base  as  the  double  platinum  salt. 


msTON.  61 

As  above  remarked,  Kossel  considers  the  protamins  as  tlie  simplest 
proteids.  If,  as  is  thus  far  generally  the  case,  we  only  consider  such  bodies 
true  protein  substances  which  on  decomposition  not  only  yield  basic  bodies 
but  also,  and  chielly,  monamido-acids,  we  are  rather  inclined  to  consider, 
with  Kossel,  the  protamins  as  the  nucleus  of  the  proteids,  so  as  not  to 
entirely  destroy  our  conception  of  protein  bodies.  Still,  before  we  admit 
this,  the  two  following  conditions  must  be  elncidated:  1.  It  must  be  shown 
that  all  protein  substances  yield  the  three  protamin  bases  as  cleavage 
products,  a  fact  which  has  not  been  quite  positively  confirmed  (see  Elastin). 
While  IIedix  and  Bergii  '  could  not  find  either  lysin,  arginin,  or  histidin 
among  the  cleavage  products  of  elastin,  still,  on  the  contrary,  Kossel  and 
Kutschek'  have  been  able  to  detect  a  very  small  amount  of  arginin,  0.3^, 
in  the  cleavage  products  of  this  albumoid.  In  fibroin,  G.  Wetzel  ^  could 
either  not  detect  any  or  only  very  inconsiderable  quantities  of  basic  nitrogen, 
O.Oftf  of  the  total  nitrogen.  Conchiolin  yielded  8.60,^  of  the  total  nitrogen 
as  basic  nitrogen.  Among  the  decomposition  products  Wetzel  found  a 
substance  whose  hydrochloride  showed  the  same  crystallization  as  histidin 
hydrochloride,  but  had  a  different  melting-point.  2.  We  must  obtain 
further  explanation  in  regard  to  the  molecular  weight  of  peptones,  for,  as 
the  thing  stands  at  present,  the  proteid  peptone  as  well  as  the  gelatin 
peptone,  which  are  generally  considered  as  proteids,  have  a  lower  molecular 
weight  (250-400)  than  the  protamins  (salmin  751  and  sturin  879,  according 
to  Kossel). 

Histon  is  the  name  given  by  Kossel  ^  to  a  substance  isolated  by  him 
from  the  red  corpuscles  of  goose-blood.  It  is  similar  in  certain  behavior  to 
the  peptones  in  the  old  sense  (the  albumoses).  This  histon  has  the  same 
amount  of  carbon  and  hydrogen  as  ordinary  proteid,  but  contains  somewhat 
more  nitrogen,  about  18^.  When  prepared,  as  suggested  by  Kossel,  from 
blood-corpuscles  by  extraction  with  hydrochloric  acid,  precipitation  of  the 
acid  solution  by  rock  salt,  and  dialyzation  until  free  from  salt,  it  gives  the 
three  following  characteristic  reactions  in  neutral,  salt-free  solution: 
1.  The  solution  does  not  coagulate  on  boiling.  2.  With  ammonia  the  salt- 
free  solution  gives  a  precipitate  insoluble  in  an  excess  of  the  ammonia. 
3.  Nitric  acid  caused  a  precipitate,  which  disappeared  on  warming,  and 
reappeared  on  cooling. 

Later  bodies  have  been  described  as  histous  which  show  a  different 
behavior  in  one  way  or  another.     Liliexfelu  has  prepared  a  histon  from 

»  Zeitsclir.  f.  physiol.  Chcm.,  Bd.  25. 

^  Ibid.,  B(l.  25,  S.  551. 

*Ibid.,  B(l.  26. 

*  Kossel,  Zeitscbr.  f.  physiol.  Cliem.,  Bd.  8,  and  Sitzungsber.  der  Gesellsch.  zur 
BefOrd.  d.  ges.  Wissenscb.  zu  Marburg,  1897  ;  Lilienfeld,  Zeitscbr.  f.  pbysiol.  Cbem., 
Bd.  18  ;  Scbulz,  ibid.,  Bd.  24  ;  Mathews,  ibid.,  Bd.  23. 


62  TEE  PROTEIN  SUBSTANCES. 

leucocytes,  whose  solntion  coagalated  on  boiling,  yielding  a  coagnlnm 
readily  soluble  in  mineral  acids.  This  histon  acted  like  Kossel's  histon 
■with  ammonia.  Sciiulz  considers  the  proteid,  globin,  set  free  on  the 
cleavage  of  haemoglobin,  as  a  histon,  although  it  is  extremely  soluble  in 
ammonia  and  does  not  dissolve  in  an  excess  of  ammonia,  only  in  the  presence 
of  ammonium  chloride.  Mathews  has  isolated  a  body,  which  he  calls 
arhacin,  from  the  spermatozoa  of  the  sea-urchin  (arbacia),  and  which  he 
considers  as  a  histon,  but  which  differs  from  the  other  histons  in  that  it 
cannot  be  precipitated  by  ammonia.  The  neutral  solution  of  this  histon  is 
precipitated  by  the  above-mentioned  (page  GO)  protamiu  precipitatants. 
It  has  not  been  shown  how  the  other  so-called  histons  act  with  these  pre- 
cipitants. 

It  seems  that  bodies  of  various  kinds  have  been  described  as  histons, 
therefore  the  author  does  not  feel  justified  in  giving  a  clear  and  precise 
definition  of  histon.  According  to  Kossel  the  histons  are  probably  com- 
binations of  protamins  and  proteid. 

R^  Hydrolytic  Cleavage  Products  of  the  Protein  Substances.' 
1.  Monamido  Acids. 

Leucin,  C.HulS^Oj,  or  amido-caproic  acid,  more  recently  called 
a-amido^isobutylacetic  acid,  (CH3),CH.CH,.CH(NHJ.C00H.  Leucin  is 
formed  not  only  in  the  trypsin  digestion  of  proteids,  but  also  from  the 
protein  substances  by  their  decomposition  on  boiling  with  diluted  acids  or 
alkalies,  by  fusing  with  alkali  hydrates,  and  by  putrefaction.  Because  of 
the  ease  with  which  leucin  and  tyrosin  are  formed  in  the  decomposition  of 
protein  substances,  it  is  difficult  to  positively  decide  whether  these  bodies 
when  found  in  the  tissues  are  constituents  of  the  living  body  or  are  only  to 
be  considered  as  decomposition  products  formed  after  death.  Leucin  has 
been  found  as  a  normal  constituent  of  the  pancreas  and  its  secretion,  in  the 
spleen,  thymus,  and  lymph-glands,  in  the  thyroid  gland,  in  the  salivary 
glands,  in  the  kidneys,  brain,  and  liver.  It  also  occurs  in  the  wool  of 
sheep,  in  dirt  from  the  skin  (inactive  epidermis)  and  between  the  toes,  and 
its  decomposition  products  have  the  disagreeable  odor  of  the  perspiration  of 
the  feet.  It  is  found  pathologically  in  atheromatous  cysts,  ichthyosis  scales, 
pas,   blood,    liver,    and   urine    (in  diseases  of   the   liver   and   phosphorus 

'  As  it  is  not  -within  the  scope  of  this  work,  we  cannot  enter  into  details  in  regard  to 
all  the  cleavage  products  of  the  protein  substances.  These  may  be  found  in  liandbooks 
of  chemistry.  For  this  reason  the  most  important  cleavage  products  of  proteids  will  be 
given  in  the  appendix  to  the  protein  substances,  carnic  acid  and  peptones  having  already 
been  described.  For  practical  reasons  the  two  amido  acids,  leucin  and  tyrosin,  will  be 
treated  of  together,  although  it  would  je  more  theoretically  correct  to  treat  the  acids  of 
the  aliphatic  and  aromatic  series  separately. 


LEUCIN.  63 

poisoning).  Leuciu  occurs  often  in  invertebrates  and  also  in  the  plant 
kingdom.  On  hydrolytic  cleavage  various  protein  substances  yield  different 
amounts  of  lencin.  Erlenmeyeh  and  Schuffer  obtained  3G-45,^  from 
the  cervical  ligament,  Coiix  32^  from  casein,  and  Nexcki  1.6-Z^  from 
gelatin.' 

Leucin  has  been  prepared  synthetically  by  IIufner'  from  isovaleralde- 
hyde-ammonia  and  hydrocyanic  acid.  This  leucin  is  optically  inactive. 
Inactive  leucin  may  also  be  prepared,  as  shown  by  E.  Schulze  and 
BossHARD,'  by  the  cleavage  of  proteids  with  baryta  at  1G0°  C.  or  on  heating 
ordinary  leucin  with  baryta-water  to  the  same  temi)erature.  The  la^vo- 
rotatory  modification  may  be  formed  from  the  inactive  leucin  by  the  action 
of  penicillum  glaucum.  The  leucin  obtained  in  the  pancreatic  digestion  of 
proteids,  as  well  as  in  their  cleavage  with  hydrochloric  acid,  seems  always  to 
be  the  dextro-rotatory  variety.  Cohn  '  has,  however,  obtained  a  leucin 
differing  from  tiie  ordinary  leucin  in  the  tryptic  digestion  of  fibrin. 
HuFXER  has  prepared  an  isomer  of  leucin  from  monobromcaproic  acid  and 
ammonia.  It  is  a  question  whether  there  exist  natural  leucins  correspond- 
ing to  normal  caproic  acid.  On  oxidation  the  leucins  yield  the  correspond- 
ing oxyacids  (leuciiiic  acids).  Leucin  is  decomposed  on  heating,  evolving 
carbon  dioxide,  ammonia,  and  amylamin.  On  heating  with  alkalies,  as  also 
in  putrefaction,  it  yields  valerianic  acid  and  ammonia. 

Leuciu  crystallizes  when  jiure  in  shining,  white,  very  thin  plates,  usually 
forming  round  knobs  or  balls,  either  appearing  like  hyalin  or  alternating 
light  or  dark  concentric  layers  which  consist  of  radial  groups  of  crystals. 
Leucin  as  obtained  from  the  animal  fluids  and  tissues  is  very  easily  soluble 
in  water  and  rather  easily  in  alcohol.  Pure  leucin  is  soluble  with  difficulty; 
according  to  certain  statements  it  dissolves  in  about  29  parts  of  water  at 
ordinary  temperatures  or  little  higher,  and  according  to  others  in  4G  parts. 
This  difference  may  be  due,  according  to  Gmelin,'  to  the  fact  that  the 
optically  active  leucins  may  be  variable  mixtures  of  the  dextro-  and  Isvo- 
rotatory  modifications.  The  inactive  leucin  is  most  insoluble.  The  specific 
rotation  of  the  ordinary  leucin,  dissolved  in  hydrochloric  acid,  is 
(«')D  =  +  17.5. 

Leucin  is  readily  soluble  in  alkalies  and  acids.  It  gives  crystalline  com- 
pounds with  mineral  acids.     If   hydrochloric   acid  leucin  is  boiled  with 

*  Erlenraeyer  and  Scboflfer,  cited  from  Maly,  Chem.  d.  Verdauungssjlfto,  in  Her- 
mann's Haudb.  d.  Physiol.,  Bd.  5,  Theil  3,  S.  209  ;  Cohn,  Zeitschr.  f.  pbysiol.  Chem., 
Bd.  22  ;  Nencki,  Jouru.  f.  prakt.  Chem.  (N.  F.),  Bd.  15. 

2  Journ.  f.  prakt.  Chem.  (N.  F.),  Bd.  1. 

^  See  Zeitschr.  f.  pbysiol.  Chem.,  Bdd.  9  and  10. 

*  Iloppe-Seyler's  Handbucb,  6.  Aufl.,  S.  134,  and  Cohn,  Zeitschr.  f.  pbysiol.  Chem., 
Bd.  20. 

*  Zeitschr.  f.  physiol  Chem.,  Bd.  18. 


64  THE  PROTEIN  SUBSTANCES. 

aloohol  containing  3-4^  HCl  long  narrow  crystalline  prisms  of  hydro- 
chloric acid  leucinethylester  melting  at  134°  are  formed.  On  slowly  heating 
to  170°  C.  it  melts  and  sublimes  in  white,  woolly  flakes  which  are  similar 
to  sublimed  zinc  oxide.  A  marked  odor  of  amylamin  is  generated  at  the 
same  time. 

The  solution  of  leucin  in  water  is  not,  as  a  rule,  precipitated  by  metallic 
salts.  The  boiling-hot  solution  may,  however,  be  precij^itated  by  a  boiling- 
hot  solution  of  copper  acetate,  and  this  is  made  use  of  in  separating  leucin 
from  other  substances.  If  the  solution  of  leucin  is  boiled  with  sngar  of 
lead  and  then  ammonia  be  added  to  the  cooled  solution,  shining  crystalline 
leaves  of  lencin-lead  oxide  separate.  Leucin  dissolves  copper  oxyhydrate 
but  does  not  red  nee  on  boiling. 

Leucin  is  recognized  by  the  appearance  of  the  balls  or  knobs  under  the 
microscope,  by  its  action  when  heated  (sublimation  test),  and  by  Scherer's 
test.  This  last  consists  in  the  lencin  yielding  a  colorless  residue  when 
carefully  evaporated  with  nitric  acid  on  platinum-foil,  and  this  residue 
when  warmed  with  a  few  drops  of  caustic  soda  gives  a  color  varying  from  a 
pale  fellow  to  brown  (depending  on  the  purity  of  the  leucin),  and  on 
further  concentrating  over  the  flame  it  agglomerates  into  an  oily  drop  which 
rolls  about  on  the  foil. 

Tyrosin,  CJI,,]SrO„  or  jy-oxYPHENYL-AMiDOPROPiONic  acid,  HO.C^H^.- 
C3H,(]SrH5).COOH,  is  derived  from  most  protein  substances  (not  gelatin 
and  reticulin)  under  the  same  conditions  as  leucin,  which  it  habitually 
accompanies.  From  genuine  proteids  such  as  casein  3-4,^,  from  horn  sub- 
stance 1-0 fo,  from  elastin  0.25^,  and  from  fibroin  about  b<fo  have  been 
obtained  by  Weyl  and  others.'  It  is  especially  found  with  leucin  in  large 
quantities  in  old  cheese  {Tvpos),  from  which  it  derives  its  name.  Tyrosin 
has  not  with  certainty  been  found  in  perfectly  fresh  organs.  It  occurs  in 
the  intestine  in  the  digestion  of  albuminous  substances,  and  it  has  about 
the  same  physiological  and  pathological  importance  as  leucin. 

Tyrosin  was  prepared  by  Erlenmeyer  and  Lipp'  from  p-amido- 
phenylalanin  by  the  action  of  nitrous  acid.  On  fusing  with  caustic  alkali 
it  yields  p-oxybenzoic  acid,  acetic  acid,  and  ammonia.  On  putrefaction  it 
may  yield  p-hydrocoumaric  acid,  oxyphenyl-acetic  acid,  and  j)-cresol. 

Tyrosin  in  a  very  impure  state  may  be  in  the  form  of  balls  similar  to 
leucin.  The  purified  tyrosin,  oti  the  contrary,  appears  as  colorless,  silky, 
fine  needles  which  are  often  grouped  into  tufts  or  balls.  It  is  soluble  with 
difficulty  in  water,  being  dissolved  by  2454  parts  water  at  -{-  20°  C.  and  154 
parts  boiling  water,  separating,  however,  as  tufts  of  needles  on  cooling.     It 

>  See  Maly,  1.  c,  Bd.  5,  Tbeil  2,  S.  212  ;  R.  Cobn,  1.  c;  Weyl,  Ber.  d.  deutsch.  chem. 
Gesellscli.,  Bd.  21. 

■  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  15. 


TTliOSIN.  65 

dissolves  more  easily  in  the  presence  of  alkalies,  ammonia,  or  a  mineral  acid. 
It  is  difficultly  soluble  in  acetic  acid.  Crystals  of  tyrosin  separate  from  an 
aninioniacal  solution  on  the  siiontaneous  evaporation  of  the  ammonia.  The 
solution  of  the  tyrosin  obtained  from  protein  substances  by  the  action  of 
acids  has  always  a  faint  laevo-rotatory  power.  Tyrosin  prepared  synthetically 
or  by  decomposition  of  proteids  by  baryta  is  optically  inactive.'  Tyrosin  is 
not  soluble  in  alcohol  or  ether.  It  is  identified  by  its  crystalline  form  and 
by  the  following  reactions : 

Piria's  Test.  Tyrosin  is  dissolved  in  concentrated  sulphuric  acid  by 
the  aid  of  heat,  by  which  tyrosin-siilphuric  acid  is  formed;  it  is  allowed  to 
cool,  diluted  with  water,  neutralized  by  BaCO, ,  and  filtered.  On  the  addi- 
tion of  a  solution  of  ferric  chloride  the  filtrate  gives  a  beautiful  violet  color. 
This  reaction  is  disturbed  by  the  presence  of  free  mineral  acids  and  by  the 
addition  of  too  much  ferric  chloride. 

IIoFMAXX's  Test.  If  some  water  is  poured  on  a  small  quantity  of 
tyrosin  in  a  test-tube  and  a  few  drops  of  Millox's  reagent  added  and  then 
the  mixture  boiled  for  some  time,  the  liquid  becomes  a  beautiful  red  and 
then  yields  a  red  precipitate.  Mercuric  nitrate  may  first  be  added,  then, 
after  this  has  boiled,  nitric  acid  containing  some  nitrous  acid. 

Scherer's  Test.  If  tyrosin  is  carefully  evaporated  to  dryness  Avith 
nitric  acid  on  jjlatinum-foil,  a  beautiful  yellow  residue  (nitro-tyrosin  nitrate) 
is  obtained,  which  gives  a  deej)  reddish-yellow  color  with  caustic  soda. 
This  test  is  not  characteristic,  as  other  bodies  give  a  similar  reaction. 

Leucin  and  tyrosin  may  be  prepared  in  large  quantities  by  boiling 
albuminous  bodies  or  albuminoids  with  dilute  mineral  acids.  Ordinarily 
we  boil  hoof-shavings  {'I  2'>arts)  with  dilute  sulphuric  acid  (5  jiarts  concen- 
trated acid  and  13  parts  water)  for  ^-i  liours.  After  boiling  the  solution  it 
is  diluted  with  water  and  neutralized  while  still  warm  with  milk  of  lime  and 
then  filtered.  The  calcium  sulphate  is  repeatedly  boiled  with  water,  and 
the  several  filtrates  are  united  and  concentrated.  The  lime  is  precij^itated 
from  the  concentrated  liquid  by  oxalic  acid  and  the  precipitate  filtered  off, 
repeatedly  boiled  with  water,  all  filtrates  united  and  evaporated  to  crystal- 
lization. "What  first  crystallizes  consists  chiefly  of  tyrosin  with  only  a  little 
leucin.  By  concentration  a  new  crystallization  may  be  produced  in  the 
mother-lifiuor,  which  consists  of  lencin  with  some  tyrosin.  To  separate 
leucin  and  tyrosin  from  each  other  their  different  solubilities  in  water  may 
be  taken  advantage  of  in  preparing  them  on  a  large  scale,  but  surer  and 
better  results  are  obtained  by  tiie  following  method  of  Hlasiavetz  and 
Habermanx.''  The  crystalline  mass  is  boiled  with  a  large  quantity  of 
water  and  enough  ammonia  to  dissolve  it.  To  this  boiling-hot  solution 
enough  basic  lead  acetate  is  added  until  the  precipitate  formed  is  nearly 
white;  now  filter,  heat  the  light  yellow  filtrate  to  boiling,  neutralize  with 

'  See  Mauthner,  Wien.  Sitzungsber.,  Bd.  85,  and  E.  Scbulze,  Zeitschr.  f.  pbysiol. 
€bem.,  Bd.  9. 

«  Aunal.  d.  Cbem.  u.  Phann.,  Bd.  1G9,  S.  160. 


CG  THE  PROTEIN  SUBSTANCES. 

sulphuric  acid,  and  filter  while  boiling  hot.  After  cooling,  nearly  all  the 
tjTOsin  is  precipitated,  while  the  lencin  remains  in  the  solution.  The 
tyrosin  may  be  purified  by  recrystallizing  from  boiling  water  or  from 
ammoniacal  water.  The  above-mentioned  mother-liquor  rich  in  lencin  is 
treated  with  H^S,  the  filtrate  concentrated  and  boiled  with  an  excess  of 
freshly  precipitated  copper  oxyhydrate.  A  part  of  the  leucin  is  precipitated, 
and  the  residue  remains  in  the  solution  and  partly  crystallizes  as  a  cuprous 
compound  on  cooling.  The  copper  is  removed  from  the  jorecipitate  and 
solution  by  means  of  H,S,  the  filtrate  decolorized  when  necessary  with 
animal  charcoal,  strongly  concentrated  and  allowed  to  crystallize.  The 
leucin  obtained  from  the  precipitate  is  quite  pure,  while  that  from  the  solu- 
tion is  somewhat  contaminated. 

If  one  is  working  with  small  quantities,  the  crystals,  which  consist  of  a 
mixture  of  the  two  bodies,  may  be  dissolved  in  water  and  this  solution 
precijiitated  with  basic  lead  acetate.  The  filtrate  is  treated  with  H^S,  the 
new  filtrate  evaporated  to  dryness,  and  the  residue  treated  with  warm 
alcohol,  which  dissolves  the  leucin  but  not  the  tyrosin.  The  remaining 
tyrosin  is  purified  by  recrystallization  from  ammoniacal  alcohol.  Lencin 
may  be  purified  by  recrystallization  from  boiling  alcohol,  or  by  precipitating 
it  as  leucin  lead  oxide,  treating  the  j^recipitate  suspended  in  water  with 
HjS  and  evaporating  the  filtered  solution  to  crystallization.  In  purifying 
crude/  leucin  KoHMANosr '  prejiares  the  hydrochloric  acid  comjDound,  and 
purifies  by  solution  in  a  little  water,  and  recrystallizes  by  cooling  the  solu- 
tion, and  from  these  he  prepares  the  hydrochloric  acid  leucinethyl  ester. 

To  detect  the  presence  of  leucin  and  tyrosin  in  animal  fluids  or  tissues 
the  proteids  must  first  be  removed  by  coagulation  with  the  addition  of 
acetic  acid  and  then  precipitated  by  basic  lead  acetate.  The  filtrate  is 
treated  with  H^S,  this  filtrate  evaporated  to  a  sirup  or  to  dryness,  and  the 
two  bodies  in  the  resid^^e  are  separated  from  each  other  by  boiling  alcohol 
and  then  purified  as  above  stated. 

Glycocol  1,  or  araido-acetic  acid.  This  acid  has  not  been  oblained  as  a  cleavage  product 
of  true  proteids,  but  only  in  the  cleavage  of  gelatin  and  other  albuminoids.  As  glycocol! 
is  of  greater  interest  as  a  cleavage  product  of  gl3^cocholic  acid  and  certain  other  conju- 
gated acids,  it  will  be  treated  of  iu  Chapter  VIII. 

Alanin,  CJIvNO, ,  or  a-amido  projMouic  acid,  CH3.CH(NHs)C00H,  has  been  ob- 
tained by  TVevl^  as  a  cleavage  product  of  fibroin  fiom  raw  silk.  Cystin,  occurring 
occa.sionally  in  the  urine,  is  considered  as  a  derivative  of  alanin. 

Phenylalanin,  or  «-phenylamido])ropionic  acid,  C6H5.C'H2.CH(NH2)COOH,  first  ob- 
tained by  ScnuLZE  and  BAKBiEia  as  a  cleavage  product  of  vegetable  proteid.  The  for- 
mation of  this  acid  in  the  cleavage  of  casein  with  hydrochloric  acid  and  tin  chloride 
is  also  proliablo  according  to  E.  Sciiui.ZE.^ 

Butalanin,  (JjI.iNO,,  or  o-aniidovalerianic  acid,  CH2(ISrH2)(CHa)3COOH.  This  acid 
■was  lirst  detected  in  tl)e  pancreas  by  v.  Gorup-Besanez,  ihen  b)'  Schulze  and  Barbieri 
in  lupin  seeds,  also  by  E.  and  H.  Salkowski  in  the  putrefaction  of  fibrin,  meat  and 
gelatin  {II.  Salkowski),  and  by  Siegfried  among  the  cleavage  products  of  reticulin, 
and  by  Zalocostas*  among  those  of  spongin. 

Tliis  acid  forms  colorless  leaves  or  starry  groups  of  needles.  It  melts  at  157-158° 
with  decomposition.  It  is  readily  soluble  in  water,  dissolves  with  difficulty  in  boiling 
alcohol,  but  is  nearly  insoluble  in  alcohol  and  ether. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  30,  S.  1980. 

^  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  21. 

2  Schulze  and  Barbieri,  ihid.,  Bd.  16  ;  E.  Schulze,  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 

*  V.  Gorup-Besan<z,    Annul,    d.    Chem.  u.    Pharm.,  Bd.  98  ;  Schulze  and  Barbieri, 


ASPARTIC  AND   GLUTAMIC  ACIDS.  67 

Aspartic  Acid,  C,II,XO^,  or  amido-succixic  acu),  CJI,(XlIJ.(COOn).^- 
This  acid  is  obtained  in  the  trypsin  digestion  of  fibrin  and  gelatin.  It  may 
also  be  obtained  by  the  decomposition  of  albuminous  bodies  or  albuminoids 
with  acids.  IIla'Siwetz  and  IIahhu.mann'  '  obtained  23.8,^  aspartic  acid, 
although  not  quite  pure,  from  ovalbumin  and  0.3;o  from  casein.  It  is  very 
widely  diffused  in  the  vegetable  kingdom  as  the  amid  aspakagixe  (amido- 
succinic-acid  amid),  Avhich  seems  to  be  of  the  greatest  importance  in  the 
development  and  formation  of  the  albuminous  bodies  in  the  plants. 

Aspartic  acid  dissolves  in  "^oG  parts  water  at  +  10°  C.  and  in  18.G  parts 
boiling  water,  and  crystallizes  on  cooling  as  rhombic  prisms.  The  acid 
prepared  from  protein  substances  is  optically  active,  and  is  dextrogyrate  in 
a  solution  strongly  acid  with  nitric  acid,  and  dextrogyrate  or  la^vogyrate  iu 
a  watery  solution,  dependent  upon  the  temperature.'  It  forms  with  cojiper 
oxide  a  crystalline  combination  which  is  soluble  in  boiling-hot  Avater  and 
nearly  insoluble  in  cold  water,  and  which  may  be  used  in  the  preparation  of 
the  pure  acid  from  a  mixture  with  other  bodies.  In  regard  to  methods  of 
preparation  see  Hlasiwetz  and  Habermaxx,  and  E.  Schulze.' 

Glutamic  Acid,  CJl^XO^,  or  amido-ptrotartaric  acid,  C3lI^(XHJ. 
(C'OOH)j.  Tliis  acid  was  first  found  am'ong  the  cleavage  products  of 
vegetable  proteids  by  Ritthausen  and  Kreusler.  Since  then  Hlasiwetz. 
and  Habermaxx  have  found  it  among  the  cleavage  jiroducts  of  animal, 
proteids  and  obtained  29^  glutamic  acid  from  casein.  It  has  also  been- 
prepared  by  Siegfried  from  the  albuminoid,  reticnlin.* 

Glutamic  acid  crystallizes  in  rhombic  tetrahedra  or  octahedra  or  iu  small 
leaves.  It  melts  at  135-140°  with  partial  decomposition.  It  dissolves  in 
100  parts  water  at  1G°  C.  and  in  1500  parts  80^  alcohol.  It  is  insoluble  in 
alcohol  and  ether.  The  glutamic  acid  obtained  from  proteids  by  boiling 
with  an  acid  is  dextro-rotatory,  while  that  obtained  by  heating  with  barium 
hydrate  is  optically  inactive.  It  forms  a  beautifully  crystalline  combination 
with  hydrochloric  acid,  which  is  nearly  insoluble  in  concentrated  hydro- 
chloric acid.  This  combinatior.  is  used  in  the  isolation  of  glutamic  acid.. 
On  boiling  with  copper  oxyhydrate  a  beautiful  crystalline  copper  salt,  which 

Journ.  f.  prakt.  Chem.  (N.  F.).  Bd.  27  ;  E.  and  H.  Salkowski,  Ber.  d.  deutsch.  chem. 
Gesellscb.,  Bd.  16  ;  H.  Salkowski,  ibid.,  Bd.  31  ;  Siegfried,  see  foot-note,  page  57  ;  Za- 
locoslas,  Compt.  rend.,  107. 

'  Anual.  d.  Chem.  u.  Pliarm.,  Bdd.  159  u.  169. 

'  See  Landolt,  Das  optiscbe  Dreluuigsvermogen  org.  Substanzen,  Braunsckweig^ 
1879,  and  Cook,  Ber.  d.  deutsch.  chem.  Gesellscb.,  Bd.  30. 

'Hlasiwetz  and  Habermunn.  Annal.  d.  Chem.  u.  Pharm.,  Bd.  1G9 ;  E.  Scbuize,. 
Zeitscbr.  f.  physiol.  Chem.,  Bd.  9. 

••  Rittbaus  u  and  Kreusler,  Journ.  f.  prakt.  Chem.  (N.  F.),  Bd.  3;  Hlasiwetz  and 
Ilabermann,  1.  c,  Bd.  159;  Siegfried,  1.  c.,  foot-note,  page  57. 


•68  THE  PROTEIN  SUBSTANCES. 

is  soluble  with   difficulty,   is  obtained.     In  regard   to    the  preparation   of 

glutamic  acid  see  Hlasiwetz  and  Habermann,  and  E.  Schulze.' 

Orloff-  makes  use  of  the  nickel  salts  in  the  separation  of  the  various  amide  acids. 
Gh'COCoU  and  alauin  give  cr3'stalliue  salts,  which  are  soluble  with  difhculty  on  boiling 
with  an  excess  of  nickel  carbonate.  Aspartic  acids  give  a  non-crystalline  nickel  salt 
which  is  readily  soluble,  while  leuciu  does  not  give  any  nickel  salt  on  boiling  with  nickel 
carbonate. 

2.  Basic  Bodies. 

The  most  important  basic  products  of  hydrolytic  cleavage  of  protein 
snbst:ances  are  lysin  (lysatin),  arginin,  and  histidin.  These  are  called  hexon 
bases  by  Kossel. 

Lysin,  C,H,^X^O,,  probably  diamido-capeoic  acid,  CJi„(N"Hj2C00H, 

is    homologous    to    ornithin    (diami do- valerianic   acid  ?).     Lysin    has   been 

obtained  by  Drechsel  and  his  pupils  not  only  from  different  proteids,  but 

also  from  several  albuminoids  on  boiling  them  with  acids.     It  is  also  formed 

in  the  tryptic  but  not  in  the  pej)tic  digestion  of  proteids,  and  also  in  the 

cleavage  of  protamins  (Kossel).'     Lysin  is  readily  soluble  in  water,  but 

does/not  crystallize.     It  is  dextro-rotatory,  but  becomes  optically  inactive  on 

hewing  with  barium  hydrate  to  150°  C.     With  hydrochloric  acid  it  gives 

two  hydrochlorides,  and  with  platinum  chloride  it  gives  a  chloroplatinate 

precipitable  by  alcohol  with  the  composition  CJIj.N'^O^.H^PbClg  +  C,H^OH. 

Lysin  gives   two  silver  salts,   one   of   which   has   the  formula  Ag]Sr03  -j- 

€JI,,N,0,,  and  the  other  with    the  formula  AgN03  -f  C„H,,N,0,.H^^03 

(Hedix).     It   gives   no   silver   combination   insoluble   in   soda  (Kossel). 

With  benzoylchloride  and  alkali  lysin  forms  a  conjugated  acid,  lysiiric  acid, 

CJI,„Xj02(C,H^0),0j  (Drechsel),  which  is  homologous  with  ornithuric 

acid,  and  decomposes  into  benzoic  acid  and  lysin  on  being  heated   with 

concentrated  hydrochloric  acid  to  140-150°  C."     Lysuric  acid  may  be  used 

in  the  separation  of  lysin,  first  preparing  the  acid  barium  salt  (C.  Will- 

DENOW  '). 

Ornithin,  CBHiaNiOj,  probably  diamido-valerianic  acid,  C4H7(ISrH2)5COOH.  It  is 
formed  besides  benzoic  acid  in  the  cleavage  of  the  conjugated  ornithuric  acid,  discovered 
by  Jaffe,  and  which  is  eliminated  by  birds  on  feeding  benzoic  acid.  It  is  also  pro- 
duced with  urea  in  the  cleavage  of  arginin  with  baryta-water  (Schulze  and  Winter- 
stein*).  Ornithin  gives  a  salt  crystallizing  in  broad  colorless  leaves,  with  nitric  acid. 
It  gives  an  odor  similar  to  semen  ou  warming  with  caustic  soda.     On  putrefaction 


'  Hlasiwetz  and  Habermann,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  169  ;  E.  Schulze, 
Zcit.schr.  f.  physiol.  Chem.,  Bd.  9. 

'•'  Cenlralbl.  f.  d.  med.  Wissensch.,  1897,  S.  642. 

^  The  works  on  lysin  and  lysatin  may  be  found  in  Drechsel :  Der  Abbau  der 
EiwcissloUe  in  Du  Bois-Reymond's  Arch.,  1891,  and  also  Hedin,  Zeitschr.  f.  physiol. 
Chem..  Bd.  21  ;  Kossel,  ibid.,  Bd.  25. 

*  Drechsel,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  28. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  25. 

*  .Taffe,  ibid.,  Bdd.  10  and  11  ;  Schulze  and  Wiutersteiu,  ibid.,  Bd.  30. 


BASIC  BODIES.  69 

Elmnokr'  has  obtained  putrescin,  which  shows  that  In  ornithi'n  an  amido  group  fakes 
the  0  jiosition. 

Diamido  acetic  Acid,  CalloNaOj  =  CII(NII  .)A"OOII,  was  obtained  by  DniiciiSEL* 
HiiKiim'  tlie  cleavage  products  on  boiling  proteids  with  tin  and  hydrochloric  acid.  It 
iryslallizes  in  prisms  and  forms  a  moubenzoyl  combination,  which  is  not  very  soluble  iu 
water,  and  nearly  insoluble  iu  alcohol,  and  which  is  used  iu  tJie  isolation  of  the  acid. 

Lysatin  or  Lysatinin.  The  formula  of  this  substance  is  either 
0,n,,X,0,  or  C'JIjjJS'jO  -j-  11,0.  In  the  first  case  the  base  is  homologOTtS 
to  creatiti,  CJI,X,0, ,  in  the  other  case  to  creatinin,  C\II,X,0,  and  it  is 
for  this  reason  the  body  is  called  lysatin  as  well  as  lysatinin.  This  base  is 
formed  under  the  same  conditions  as  lysin,  and  according  to  Hedin  it  is 
perhaps  only  a  mixture  of  lysin  and  arginin. 

The  base  readily  deconi])oses,  and  on  boiling  with  baryta-water  it  yields 
urea.  It  gives  a  double  silver  salt  with  the  formula  CJIjjN^Oj.IIXO,  + 
AgNOj ,  which  is  soluble  in  water  but  insoluble  in  alcohol-ether,  and  which 
is  used  in  the  separation  and  i^urification  of  the  base. 

Arginin,  CJIj^jS'^O,,  was  first  discovered  by  Schulze  and  Steigek  in 
etiolated  lupin  and  pumpkin  sprouts.  It  was  later  detected  by  Hedin  in 
the  cleavage  products  of  horn  substance,  gelatin,  and  several  proteid  bodies. 
IIedix  obtained  the  following  amounts  of  arginin  from  horn  substance^ 
gelatin,  conglutin,  albumin  from  egg-yolk,  ovalbumin,  and  casein  respec- 
tively: 2.25;  2.G;  2.75;  2.3;  0.8;  0.8^.  Schulze  and  IxOxgger  obtained 
specially  large  quantities  of  arginin,  about  lOfo,  from  the  proteid  of  the 
conifer  seeds.  Arginin  also  occurs  among  the  products  of  trypsin  digestion 
(Kossel  and  Kutscher). 

Arginin  is  a  crystalline  substance,  which  yields  urea  and  apparently  also 
ornithin  on  boiling  with  barium  hydrate  (see  above).  Several  crystalline 
salts  and  double  salts  are  known  of  this  base,  among  which  the  silver  salt  is 
the  most  important.  The  silver  salt,  AgNO,  +  0,H,^N^O,  +  ^11,0,  sepa- 
rates on  slow  crystallization  in  beautiful  prismatic  crystals.  It  is  the  least 
soluble  of  all  the  silver  salts,  and  is  best  suited  for  the  isolation  of  the  base. 
With  silver  salt  and  free  alkali  or  barium  hydrate,  arginin  gives  an  insoluble 
silver  compound  (Kossel).' 

Histidin,  CgH^XjO, ,  was  first  discovered  by  Kossel  as  a  cleavage 
product  of  the  protamius  (sturin).  After  this  it  was  found  by  IIedix  ^ 
among  the  cleavage  products  of  proteids  on  boiling  them  with  dilute  acid, 
and  by  Kutscher  among  the  products  of  trypsin  digestion. 

Histidin  crystallizes  in  colorless  needles  or  lamellje.  Its  watery  solution 
is  not  precipitated  by  silver  nitrate  alone,  but  on  the  careful  addition  of 
ammonia  an  amorphous  precipitate  readily  soluble  in  an  excess  of  ammonia 

'  Ber.  d.  deutsch.  chem.  Gesullsch.,  Bd.  31. 

•  Ber.  d.  silchs.  Ges.  d.  Wissensch.,  Bd.  44. 

•''  Sciiulze  and  Steiger,  Zeitschr.  f.  physiol.  Chem.,  Bd.  11  ;  Uedin,  ibid.,  Bd.  21  ; 
Schulze  (and  Rongger  ,  ibid.,  Bd.  24  ;  Kutscher,  ibid.,  Bd.  25;  Kossel,  ibid. 

*  Kossel,  Sitzungsber.  d.  kgl.  Preuss.  Akad.  d.  Wissensch.,  Bd.  18,  and  Zeitschr.  f. 
physiol.  Chem.,  Bd.  25  ;  Ilediu,  ibid.,  Bd.  22. 


70  THE  PROTEIN  SUBSTANCES. 

is  obtained.  The  hydrochloride  crystallizes  in  beautiful  lamellated  crystals,' 
It  is  optically  inactive,  dissolves  rather  readily  in  water,  but  is  insoluble  in 
alcohol  and  ether.  Histidin  acts  like  arginin  with  silver  salt  and  alkali. 
Histidin  carbonate  is  precijjitated  by  mercuric  chloride  (Kossel). 

The  principle  of  the  preparation  of  these  bases  consists  in  first  precipitat- 
ing all  the  bases  with  phosiDho-tungstic  acid,  which  leaves  the  amido  acids 
in  solution.  The  precipitate  is  decomposed  in  boiling  water  with  barium 
Jiydroxide  and  the  bases  obtained  from  the  filtrate  as  silver  combinations. 
In  regard  to  details  we  refer  the  reader  to  the  above-cited  works  of  Deechsel 
and  Hedin.  Kossel  first  separates  the  histidin  from  the  other  bases  by 
precipitation  with  mercuric  chloride,  but  according  to  more  recent  investi- 
gations Kossel^  finds  that  the  mercuric  chloride  method  cannot  be  used  as 
a  general  method  of  separating  arginin  from  histidin,  because  one  can  never 
be  sure  whether  or  not  the  histidin  is  not  contaminated  with  arginin. 
According  to  Kossel  lysin  may  be  readily  prepared  as  a  picrate,  which  is 
obtained  on  adding  an  alcoholic  solution  of  picric  acid  to  a  concentrated 
watery  solution  of  the  free  base.  Arginin  may  be  separated  from  lysin  by 
precipitating  with  silver  sulphate  and  barium  hydroxide. 

'  See  Bauer,  Zeitschr.  f.  physiol.  Chem.,  Bd.  22. 
J  « Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 


CHAPTER   III. 
THE   CARBOHYDRATES. 

We  designate  with  this  name  bodies  which  are  especially  abundant  in 
the  jilant  kingdom.  As  the  protein  bodies  form  the  cliief  portion  of  the 
solids  in  animal  tissnes,  so  the  carbohydrates  form  the  chief  portion  of  the 
dry  substance  of  the  plant  structure.  They  occur  in  the  animal  kingdom 
only  in  proportionately  small  quantities  either  free  or  in  combinations  with 
more  complex  molecules,  forming  compound  proteids.  Carbohydrates  are 
of  extraordinarily  great  importance  as  food  for  both  man  and  animnls. 

The  carbohydrates  contain  carbon,  hydrogen,  and  oxygen.  The  last  two 
elements  occur  in  the  same  proportion  as  they  do  in  water,  namely,  2:1, 
and  this  is  the  reason  why  the  name  carbohydrates  has  been  given  to  them. 
This  name  is  not  quite  pertinent,  if  strictly  considered;  because  even 
though  we  have  bodies,  such  as  acetic  acid  and  lactic,  which  are  not  carbo- 
hydrates and  still  have  their  oxygen  and  hydrogen  in  the  relationship  to 
form  water,  nevertheless  we  also  have  a  sugar  (rhamnose,  CgII,,Oj)  which 
has  these  two  elements  in  another  proportion.  Heretofore  it  was  thought 
possible  to  characterize  as  carbohydrates  those  bodies  which  contained 
6  atoms  of  carbon,  or  a  multiple,  in  the  molecule,  but  this  is  not  considered 
valid  at  the  present  time.  We  have  true  carbohydrates  containing  less  than 
6  and  also  those  containing  7,  8,  and  9  carbon  atoms  in  the  molecule.  The 
carbohydrates  have  no  properties  or  characteristics  in  general  which  differ- 
entiate them  from  other  bodies;  on  the  contrary,  the  various  carbohydrates 
are  in  many  cases  very  different  in  their  external  properties.  Under  these 
circumstances  it  is  very  difficult  to  give  a  positive  definition  of  carbo- 
hydrates. 

From  a  chemical  standpoint  we  can  say  that  all  carbohydrates  are 
aldehyde  or  ketone  derivatives  of  polyhydric  alcohols.  The  simplest  carbo- 
hydrates, the  simple  sugars  or  monosaccharides,  are  either  aldehyde  or 
ketone  derivatives  of  these  alcohols,  antl  the  more  complex  carboliydratea 
seem  to  be  derived  from  these  by  the  formation  of  anhydrides.  It  is  a  fact 
that  the  more  complex  carbohydrates  yield  two  or  even  more  molecules  of 
the  simple  sugars  when  made  to  undergo  hydrolytic  splitting. 

The  carbohydrates  are  generally  divided  into  three  chief  groups,  namely» 
monosaccharides,  disaccharides,  and  polysaccharides. 

71 


72  THE  CARBOHYDRATES. 

Our  knowledge  of  the  carbohydrates  and  their  strnctaral  relationships 
has  been  very  mncli  extended  by  the  pioneering  investigations  of  Kiliais'i  ' 
and  especially  those  of  E.  Fischer.' 

As  the  carbohydrates  occur  chiefly  in  the  plant  kingdom  it  is  naturally 
not  the  place  here  to  give  a  complete  discussion  of  the  numerous  carbo- 
hydrates known  up  to  the  present  time.  According  to  the  plan  of  this 
work  it  is  only  possible  to  give  a  short  review  of  those  carbohydrates  which 
occur  in  the  animal  kingdom  or  are  of  special  importance  as  food  for  man 
and  animals. 

Moiiosaccliarid.es. 

All  varieties  of  sugars,  the  monosaccharides  as  well  as  disaccharides,  are 
characterized  by  the  termination  "  ose,"  to  which  a  root  is  added  signifying 
their  origin  or  other  relations.  According  to  the  number  of  carbon  atoms, 
or  more  correctly  oxygen  atoms,  contained  in  the  molecule  the  monosaccha- 
rides are  divided  into  trioses,  tetroses,  pentoses,  hexoses,  hepioses,  and  so  on. 

All  monosaccharides  are  either  aldehydes  or  ketones  of  polyhydric 
alcohols.  The  first  are  termed  aldoses  and  the  other  ketoses.  Ordinary 
glucosfe  is  an  aldose,  while  ordinary  fruit-sugar  (levulose)  is  a  ketose.  The 
difference  may  be  shown  by  the  structural  formula  of  these  two  varieties  of 
sugar : 

Glucose    =  CH,(OH).CH(OH).CH(OH).CH(OH).CH(OH).CHO; 
Levulose  =  CH,(OH).CH(OH).CH(OH).CH(OH).CO.OH,(OH). 

A  difference  is  also  observed  on  oxidation.  The  aldoses  can  be  con- 
verted into  oxyacids  having  the  same  quantity  of  carbon,  while  the  ketoses 
yield  acids  having  less  carbon.  On  mild  oxidation  the  aldoses  yield  mono- 
basic oxyacids  and  dibasic  acids  on  more  energetic  oxidation.  Thus 
ordinary  glucose  yields  gluconic  acid  in  the  first  case  and  saccharic  acid  in 
the  second. 

Gluconic  acid    =  CH,(OII).[CH(Ori)],.COOII ; 
Saccharic  acid  =  COOH.[CII(OH)],.COOH. 

The  monobasic  oxyacids  are  of  the  greatest  importance  in  the  artificial 
formation  of  the  monosaccharides.  These  acids,  as  lactones,  can  be  con- 
verted into  their  respective  aldehydes  (corresponding  to  the  sugars)  by  the 
action  of  nascent  hydrogen.  On  the  other  hand  they  may  be  transformed 
into  stereo-isomeric  acids  on  heating  with  chinolin,  pyridin,  etc.,  and  the 
stereo-isomeric  sugars  may  be  obtaihed  from  these  by  reduction. 

'  Ber.  (1.  deutsdi.  chem.  Gesellscb.,  Bdd.  18,  19,  and  20. 

'  See  E.  Fisclier's  lecture  :  "  Syutlieseii  in  der  Zuckergrnppe,"  Ber.  d.  deutsch.  chem. 
Gesellscb.,  Bd.  2'd,  S.  2114.  .  An  excellent  work  on  Carbohydrates  is  Tollen's  "Kurzes 
Haudbuch  der  Kohlebydrate,"  Breslau,  Bd.  2,  1895,  and  Bd.  1,  2  Auflage,  1898,  which 
gives  a  complete  review  of  the  literature. 


MONOSACCITAIilDES.  7a 

Nnmerona  isomers  occur  among  tlie  monosaccliarides,  and  especially  ia 
the  liexose  group.  Iti  certain  cases,  as  for  instance  in  glucose  and  levulose, 
we  are  dealing  with  a  different  constitution  (aldoses  and  ketoses),  l)ut  in 
most  cases  we  have  stereo-iaomerism  due  to  the  presence  of  asymmetric 
carbon  atoms. 

The  monosaccharides  are  converted  into  the  corresponding  alcohois  by 
nascent  hydrogen.  Thus  akabinose,  which  is  a  pentose,  CJI,/J^,  is 
transformed  into  the  pentatomic  alcohol,  arabit,  CJI^^O^.  The  three 
hexoses,  glucose,  levulose,  and  galactose,  C,II„0,,  are  transformed 
into  the  corresponding  three  hexites,  sorbite,  mannite,  and  ijulcite, 
CJI,,0,.  In  these  reductions  a  second  isomeric  alcohol  is  also  obtained  as 
in  the  reduction  of  levulose  besides  mannite  also  sorbite.  Inversely,  the 
corresponding  sugars  may  be  prepared  from  polyhydric  alcohols  by  careful 
oxidation. 

Similar  to  the  ordinary  aldehydes  and  ketones  the  sugars  may  be  made 
to  take  up  hydrocyanic  acid.  Cyanhydrines  are  thus  formed.  These 
addition  products  are  of  special  interest  in  that  they  make  the  artificial 
preparation  possible  of  sugars  rich  in  carbon  from  sugars  poor  in  carbon. 

As  example,  if  we  start  from  clucose  we  obtain  glucocyanbydrin  on  the  addition  of  liy- 
drocyanicacid:  CH3(OH).[CH(OH)]^.COH-t-HCN  =  CH2(OH).[CH(OH)],.CH(OH).CN. 
Ou  the  saponiticatioii  of  glucocyanhydrin  tlie  corresponding oxyacid  is  formed:  CHalOH) 
[CH(OM)],.CH(OH).CN  +  2H,0  =  CH,(OH).[ClI|OH)]4.CHiOH)COOH4-NH3.  Ej 
the  action  of  uasceul  hydrogen  on  the  lactone  of  this  acid  we  obtain  glucohentose. 
CHmO,. 

The  monosaccharides  give  the  corresponding  oximes  with  hydroxylamin  ; 
thus  glucose  yields  glucosoxime,  CH,(OH).[CH(OH)],.CH  :  N.OH.  These 
combinations  are  of  importance  on  account  of  the  fact,  as  found  by 
WoHL,'  that  they  are  the  starting-point  in  the  building  up  of  varieties  of 
sugars,  namely,  the  preparation  of  sugars  poor  in  carbon  from  those  rich  in 
carbon. 

The  monosaccharides  are  strong  reducing  bodies,  similar  to  the  alde- 
hydes. They  reduce  metallic  silver  from  ammoniacal  silver  solutions,  and 
also  several  metallic  oxides,  such  as  copper,  bismuth,  and  mercury  oxides, 
on  warming  their  alkaline  solutions.  This  property  is  of  the  greatest 
importance  in  their  detection  and  quantitative  estimation. 

The  behavior  of  the  sugars  to  phenylhydrazin  acetate  is  of  special 
importance.  Their  watery  solutions  first  yield  hydrazoxes  with  phenyl- 
hydrazin acetate,  and  then  osazones  on  lengthy  warming  in  the  water- 
bath.     The  reaction  takes  place  as  follows : 

(a)  CH,(OH).[CH(OH)],.CH(OH).CHO  +  HoKNH.CHi 

=  CH,(0H).[CH(0H)]3.CH(0H)CH  :  N.NH.CrH»  +  H...0. 
Pheuylglucoshydrazon 

•  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  2G,  S.  730. 


74  THE  CARBOHTBRATBS. 

Vb)  CH5(OH)rCH(OH)]3.CH(OH).CH  :  N.NH.CeHs  +  H.N.NH.CeHs 
"  =  CiI,(0H).[CH(0H)]3.C  .  CH  :  N.NH.CeHs 

N.NH.CbHs  +  H=0  +  H.. 
Phenylglucosazon 

The  hydrogea  is  not  evolved,  but  acts  on  a  second  molecule  of  phenylhydrazin  and 
splits  it  into  anilin  and  ammonia  : 

HoN.NH.CeHs  +  H,  =  H.N.CeHs  +  NH3. 

The  osazones  are  yellow  crystalline  combinations,  which  differ  from 
-each  other  in  melting-point,  sol  ability,  and  optical  properties,  and  hence 
have  received  great  importance  in  the  characterization  of  certain  sugars. 
They  have  also  become  of  extraordinarily  great  importance  in  the  study  of 
the  carbohydrates  for  other  reasons.  Thus  they  are  a  very  good  means  of 
precipitating  sugars  from  solution  in  which  they  occur  mixed  with  other 
bodies,  and  they  are  of  the  greatest  importance  in  the  artificial  preparation 
-of  sugars. 

On  cleavage,  by  the  short  action  of  gentle  heat  and  fuming  hydrochloric 
acid,  the  osazones  yield  phenylhydrazin  hydrochloride  and  so-called  osones, 
bodies  which  are  ketoaldehydes : 

^       CH,(OH).[CH(OH)],.C.CH:  KNH.C.H, 

N.NH.C.H,         +  2H,0  -f  3HC1 
=  2C,H,.NH.NH,.HC1  +  CH,(0H).[CH(0H)]3.C0.CH0. 

Osone 

The  ketoses  are  obtained  from  the  osones  by  reduction  with  zinc  dust 
^nd  acetic  acid: 

<:!H,(OH).[CH(OH)].CO.CHO  +  211 

=  CH,(OII).[CH(OH)],.CO.CH,(OH). 

If  we  start  with  an  aldose,  we  do  not  get  the  same  sugar  back  again,  but 
an  isomere  ketose,  and  in  this  way  we  can  convert  glucose  into  levulose. 

TVe  can  also  pass  from  the  osazones  to  the  corresponding  sugars 
(ketoses)  in  other  ways,  namely,  by  direct  reduction  of  the  osazones  with 
acetic  acid  and  zinc  dust.  The  corresponding  osamin  is  first  formed,  and 
then  on  treating  with  nitrous  acid  a  ketose  is  obtained: 

CH,(OH).[CH(OH)],.C.CII :  N.NH.C.H. 

N.NII.C.H,  +  11,0  +  4H  = 

Phenylglucosazon 

CH,(0II).[CII(0II)]3.C0.CH.(NHJ  +  C.1I..NH.NII,  +  C.H^.NH, 

Isoglucosaniia 

<JH,(0n).[CH(0II)],.C0.CH,(Nnj  +  UNO, 

=  cH,(on).[cii(on)]3.co.cn,(OH)  +  n,  +  ii,o. 

Levulose 


MONOSACCUAUIDES.  75 

From  what  has  been  stated  we  see  that  there  are  various  ways  of  prepar- 
ing sugars  artificially.  They  may  be  prepared  (1)  by  the  careful  oxidation 
of  tlie  polyhyJric  alcohols;  (2)  reduction  of  tlie  corresponding  monobasic 
oxyacids;  (;3)  splitting  of  the  osazone  with  hydrochloric  acid  and  a  reduction 
of  the  osone;  (4)  direct  reduction  of  the  osazone  and  treating  the  osamin 
with  nitrous  acid;  (5)  syntheses  from  combinations  poor  in  carbon  (see 
syntheses  of  the  hexoses). 

The  isogliicosMuiin  prepared  in  the  above  manner  from  plienyljjhicosazon  is  isomeric 
■witli  another  iilncosainin,  whicli  may  be  obtained  by  the  cleavage  of  chitin  (see  Chapter 
XVI)  with  hydrochloric  acid.  Both  glucosanuns  give  crystalline  sails  and  have  re- 
ducing i.ctions.  The  glucosamin  (from  chitin)  gives  a  dexlro-rotator}',  non-fermentable 
sugar  Willi  nitrons  sicid,  while  isoglucosamin  gives  Icvnlose.  E.  Fisciiek  is  of  the 
opinion  that  glucosamin  is  derived  fn)m  dextrose,  and  isoglucosauun  from  levnlose. 

Many  varieties  of  sugar  form  crystalline  combinations,  which  may  be  considered  as 
osamins,  with  ammonia,  when  they  are  dissolved  in  ammoniacal  methyl  alcohol  (Lobry 
DE  Bruyn)  '  They  give  no  salts  with  acids,  and  differ  from  the  other  known  isomeric 
osumius  in  this  respect. 

As  shown  by  E,  Fischer  and  his  pupils  °  the  aldoses  (also  pentoses),  as 
well  as  ketoses,  may  enter  into  an  ethereal  combination  with  alcohols  in  the 
presence  of  hydrochloric  acid.  These  combinations  are  called  glucostdes. 
Such  glucosideshave  not  only  been  obtained  with  aliphatic  alcohols,  but  also 
with  benzyl  alcohol,  polyvalent  phenols,  and  oxyacids.  The  more  compli- 
cated carbohydrates  may,  according  to  Fischer,  be  considered  as  glucosides 
of  the  sugar.  Thus  maltose  is  the  glucoside  and  lactose  the  galactoside  of 
grape-sugar. 

By  the  action  of  alkalies,  even  in  small  amounts,  as  also  of  alkaline  earths 
and  lead  hydroxide,  a  reciprocal  transformation  of  the  sugars,  such  aa 
glucose,  levulose,  and  mannose,  may  take  place  (Lobry  de  Bruyn  and 
Alberda  VAX  Ekensteix).' 

Two  other  sugars,  among  them  two  ketoses,  are  produced  by  the  action  of  potash  or 
soda  on  each  of  the  tliree  sugars,  glucose,  levulose,  and  galactose.  For  example,  from 
glucose  two  ketoses,  levulose  and  pseudoleviilose,  are  produced,  also  mannose  and  a  non- 
fermentable  sutiar,  glutose.  From  galactose  are  formed  talose  and  galtose,  besides  two 
ketoses,  tagatose  and  pseudotagatose. 

The  monosaccharides  are  colorless  and  odorless  bodies,  neutral  in  reac- 
tion, with  a  sweet  taste,  readily  soluble  in  water,  generally  soluble  with 
difiiculty  in  absolute  alcohol,  and  insoluble  in  ether,  and  some  of  which 
crystallize  well  in  the  pure  state.  They  are  optically  active,  some  lajvo- 
rotatory  and  others  dextro-rotatory;  but  there  are  also  optically  inactive 
modifications  (racemic),  which  are  formed  from  two  optically  ojiposed  com- 
ponents. 

'  Ber.  d.  deutsch.  chem.  Gcsellsch.,  Bd.  28,  S.  3082,  and  Chem.  Centralbl.,  1896, 
Bd.  2. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  26,  27,  28. 

3  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  28,  S.  3078  ;  Bull.  soc.  chim.  de  Paris  (3), 
Tome  15  :  Chem.  Centralbl.,  1896,  2.  and  1897.  2. 


7G  THE  CAIWOII  YD  RATES. 

We  designate  the  optical  activity  of  the  carbohydrates  with  the  letter  1- 
for  la3vogyrate,  d-  for  dextrogyrate,  ami  i-  for  inactive.  These  are  only 
partly  usefnl.  Thus  dextro-rotatory  glucose  is  designated  d-glncose,  Isevo- 
rotatory  1-glucose,  and  the  inactive  i-glucose.  Emil  Fischee,  has  used  these 
signs  in  another  sense,  lie  designates  by  these  signs  the  homogeneonsuess 
of  the  various  kinds  of  sugars  instead  of  their  optical  activity.  For  exam- 
ple, he  does  not  designate  the  Isevo-rotatory  levulose  1-levulose,  but 
d-levulose,  showing  its  close  relation  to  dextro-rotatory  d-glucose.  This 
designation  is  generally  accepted,  and  the  above-mentioned  signs  only  show 
the  optical  properties  in  a  few  cases. 

Specific  rotation  means  the  rotation  iu  degrees  produced  by  1  gm,  substance  dissolved 
in  1  cc.  liquid  placed  iu  a  tube  1  d.cm.  long.  The  reading  is  ordinarily  made  at 
-j-  20°  C.  and  with  a  homogeneous  sodium  light.  The  sp.  rotation  with  this  light  is  repre- 
sented by  «(D),  and  is  expressed  by  the  following  formula  :  a(D)  =  ±  — -  ,  in   which  a 

represents  the  reading  of  degrees,  1  the  length  of  the  tube  in  decimetres,  and  p  the  weight 
of  substance  iu  1  cc.  of  the  liquid.  Inversely  the  per  cent  Pof  substance  can  be  calcu- 
lated, when  the  specific  rotation  is  known,  by  the  formula  P=  — -— ,  in  which  s  repre- 
sents the  known  specific  rotation. 

A  freshly  prepared  sugar  solution  of teu  shows  another  rotation  from  when  it  is  allowed 
to  Stan  (jl  for  sometime.  If  the  rotation  gradually  diminishes,  this  is  called  birotation,  while 
a  o^radual  increase  iu  the  rotation  is  called  half-rotation.  The  birotation  and  half-rota- 
tion may  be  immediately  abolished  by  the  addition  of  very  little  ammonia  (1  p.  m.). 
C.  ScnuLTZE  and  Tollens.' 

The  change  iu  the  rotation  constant  and  the  dependence  of  this  upon  the  coucentra- 
tiou  and  teniperature  of  the  solution  depends,  according  to  Tanket-  upon  the  fact  that 
there  exist  three  different  modifications  of  each  sugar  (that  has  been  examined),  each  of 
which  with  equal  molecular  size  has  its  own  rotation  property  and  its  own  solubility  and 
can  be  converted  into  other  modifications. 

Many  monosaccharides,  but  not  all,  ferment  with  yeast,  and  it  has  been 
shown  that  only  those  varieties  of  sugar  containing  3,  G,  or  9  atoms  of 
carbon  in  the  molecule  are  fermentable  with  yeast.  Still  amongst  the 
hexoses  we  find  exceptions,  namely,  a  few  artificially  prepared  hexoses  do 
not  ferment  with  yeast.  A'arious  kinds  of  schizomycetes  cause  a  different 
fermentation,  such  as  lactic  and  butyric  acid  fermentation  and  mucilaginous 
fermentation. 

E.  Fischer'  has  shown  that  the  restricted  action  of  yeast  on  only 
certain  varieties  of  sugar  is  very  probably  in  close  connection  with  the 
stereometric  configuration  of  the  sugars.  The  active  protein  substances  of 
the  yeast,  which  are  asymmetrically  built,  only  act  on  those  varieties  of  sugar 
whose  geometric  structure  is  similar  to,  or  at  least  not  very  d liferent  from, 
the  ferment.  The  same  is  true  also  for  the  action  of  inverting  enzymes  on 
polysaccharides  and  glucosides. 


'  Annal.  d.  Clicm.  u.  Pharm.,  Bd.  271. 

=  Compt.  rend.,  Tomes  120  and  122  ;  Bull,  soc  chim.  (3),  Tomes  13  and  15. 

'  Ber.  d.  deutscli.  chem.  Gesellsch.,  Bd.  27.  The  behavior  of  various  sugars  with 
pure  yeust  and  the  conditions  for  their  fermeutatioa  has  been  studied  by  E.  Fischer  and 
H.  Thierf elder,  ibid.,  Bdd.  27  and  28. 


PENTOSES.  11 

The  simple  varieties  of  sugar  occur  in  part  in  nature  as  sucli  already 
formed,  wliicli  is  the  case  with  botii  of  the  very  important  sugars,  grape- 
sugar  and  leviilose.  They  also  occur  in  great  abundance  in  nature  as  more 
complex  carbohydrates  (tli-  and  polysaccharides);  also  as  ester  combinations 
with  dilTerent  substances,  as  so-called  glucosides. 

Among  the  groups  of  monosaccharides  known  at  the  present  time,  those 
containing  less  than  five  and  more  than  six  carbon,  atoms  in  tlie  molecule 
have  no  great  importance  in  zoo-chemistry,  although  they  are  of  high 
scientific  interest.  Of  the  other  two  groups  the  hexoses  are  of  the  greatest 
importance,  because  in  the  past  only  those  carbohydrates  with  six  carbon 
atoms  were  considered  as  true  carbohydrates.  As  the  pentoses  have  been 
the  subject  of  zoo-chemical  investigations  of  late,  they  will  also  be  given  in 
short. 

Pentoses  (CJLoOs). 

As  a  rnle  the  pentoses  do  not  occur  as  snch  in  nature,  but  are  formed  in 
the  liydrolytic  splitting  of  several  more  complex  carbohydrates,  the  so-called 
pentosanes,  especially  on  boiling  gums  with  dilute  mineral  acids.  They  exist 
very  widely  distributed  in  the  plant  kingdom,  and  are  especially  of  great 
importance  in  the  building  up  of  certain  plant  constituents.  They  liave 
only  thus  far  been  found  in  exceptional  cases  in  animals.  Salkowski  and 
Jastroavitz  have  found  a  pentose  in  the  urine  of  a  person  addicted  to  the 
morphine  habit,  and  Salkoavski  subsequently  found  it  in  two  similar  cases. 
Small  quantities  of  pentoses  have  been  detected  in  many  cases  by  Kulz  and 
Vogel'  in  the  urine  of  diabetics,  as  also  in  dogs  with  pancreas  diabetes  or 
phlorhizin  diabetes.  Pentose  also  has  been  found  by  the  author  amongst 
the  cleavage  products  of  a  nucleoproteid  obtained  from  the  pancreas,  and 
seems  also,  according  to  the  observations  of  Blumexthal,'  to  be  a  constit- 
uent of  nucleoproteids  of  various  organs  such  as  the  thymus,  thyroid,  brain, 
spleen,  and  liver. 

The  pentoses  seem  to  be  of  importance  as  food  for  herbivorous  animals. 
Salkowski  and  Ckemer'  have  shown  that  the  pentoses  xylose,  arabinose, 
and  rhamnose  are  assimilated  by  rabbits  and  hens,  and  that  these  animals 
utilize  the  pentoses,  and  even  form  glycogen  therefrom.  The  pentoses  seem 
to  be  absorbed  by  human  beings  and  to  be  utilized  in  part.  They  pass 
readily  into  the  urine.* 

'  Salkowski  and  Jastrowitz,  Ceiitralbl.  f.  d.  rned.  Wissenscb.,  1892,  S.  337  and  593  ; 
Salkowski,  Bcrl.  kliu.  Wocbenschr.,  189")  ;  Kiilz  aiul  Vogil,  Zeitscbr.  f.  Biologie, 
B(l.  32. 

'-' Hammarsten,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  19;  also  Salkowski,  Berl.  kliu. 
Wocbenscbr..  1895  ;  Blumenthal,  Zeitscbr.  f.  klin.  Med.,  Bd.  34. 

3  Salkowski,  1.  c.  Centralbl.  ;  Cremer,  Zeitscbr.  f.  Biologie,  Bd.  29. 

■•^See  Ebstein,  Vircbow's  Arab. ,129  ;  Tollens,  Bcr.  d.  dcutscb.  cbeni.  Gesellscb.,  Bd. 
39.  S.  1208;  Cremer,  1.  c;  Lindemanii  and  May,  Deutscb.  Arcb.  f.  klin.  Med.,  Bd.  56. 


78  THE  CARB0UYDRATE8. 

The  pentoses  are  non-fermentable,  reducing  aldoses.  On  heating  with, 
sulphuric  or  hydrochloric  acids  they  yield  furfurol,  but  no  levulinic  acid. 
The  furfurol  passing  over  on  distilling  with  hydrochloric  acid  may  not  only 
be  used  in  the  detection  (with  aniline  acetate  paper  which  is  colored  red 
with  furfurol),  but  also  in  the  quantitative  estimation  of  pentoses  (or 
jjentosanes).  On  warming  with  hydrochloric  acid  containing  phloroglncin 
a  beautiful  red  solution  is  the  result,  and  this  solution  gives  a  sharply 
defined  absorption  band  on  the  right  of  the  sodium  line.  The  most 
important  pentoses  are  aeabixose  and  xylose. 

Arabinose  (dextro-rotatory  arabinose,  pectin  sugar)  Is  obtained  on  boil- 
ing gum  arable  or  cherry-gum  with  2^  sulphuric  acid.  It  crystallizes,  has 
a  sweet  taste,  melts  at  about  160°,  and  is  strongly  dextro-rotatory  a(J))  — 
+  104-105°.  Its  osazon  melts  at  157-158°  C,  and  10  c.  c.  Fehling's 
solution  is  reduced  by  43  milligrams  arabinose.  The  artificially  prepared 
Itevogyrate  arabinose  as  well  as  the  optically  inactive  arabinose  are  known. 

Xylose  (wood  sugar).     This  body  is  obtained  with  the  previous  stereo- 

isomeric  pentose  on  boiling  wood  gums  with  dilute  acids.     It  forms  crystals 

melting  at    153-154°   C,  which  are  very  soluble    in  water  but  difficultly 

soluble  in  alcohol.     It  has  a  sweet  taste,  is  feebly  dextro-rotatory,  «(D)  = 

+  18.1°,  and  gives  an  osazon  which  melts  at  159-160°  C. 

Amongst  the  pentoses  we  have  ribose,  obtained  on  the  reduction  of  the  lactone  of 
ribonic  acid,  "which  is  produced  from  arobonic  acid,  lihamnose,  which  used  to  be  called 
isodulcite,  is  a  methylpentose,  C8H12O5,  and  is  obtained  from  different  glucosides 
(quercltin,  xanthorhaninin,  etc.). 

Hexoses  (C,H,,0,). 

The  most  important  and  best-known  simple  sugars  belong  to  this  group, 
and  the  remaining  bodies  considered  as  carbohydrates  (with  the  exception 
of  arabinose  and  inosite)  are  anhydrides  of  this  group.  Certain  hexoses, 
such  as  dextrose  and  levulose,  occur  in  nature  already  formed,  while  others 
are  produced  by  the  hydrolytic  splitting  of  other  more  complicated  carbo- 
hydrates or  glucosides.  Others,  such  as  mannose  or  galactose,  are  formed 
by  the  hydrolytic  cleavage  of  natural  products;  while  some,  on  the  contrary, 
such  as  gulose,  talose,  and  others,  are  obtained  only  by  artificial  means. 

All  hexoses,  as  also  their  anhydrides,  yield  levulinic  acid,  O^HgO,, 
besides  formic  acid  and  humus  substances,  on  boiling  with  dilute  mineral 
acids.  Some  of  the  hexoses  are  fermentable  with  yeast,  while  the  artificially 
prepared  liexoses  do  not,  or  at  least  only  with  great  difficulty  and  incom- 
pletely. 

Some  hexoses  are  aldoses,  while  others  are  ketoses.  Belonging  to  the 
first  group  we  have  maxxose,  olucose,  gulose,  galactose,  and  talose, 
and  to  the  other  levulose,  and  possibly  also  sorbinose.  We  differentiate 
also  between  the  d,  1,  and  i  modifications,  for  instance,  d-,  1-,  and 
i-glucose;  hence  the  number  of  isomers  is  very  great. 


IIEXOSES.  7^ 

Tlie  most  important  syntheses  of  the  carbohydrates  have  been  made  by 
E.  FiscHKU  and  his  pupils  cliiefly  within  the  members  of  the  hexose  group, 
A  short  summary  of  the  syntheses  of  liexoses  is  given  below. 

The  first  artificial  jireparutiou  of  glucose  was  made  by  Butleuow.  On  treating 
trioxyinelliylen,  a  polymer  of  formaldehyde,  with  lime-wiiter  lie  obtained  a  faintly 
sweetish  sirup  called  metlujlcniliiu.  LoEW  '  later  obtained  n  mixture  of  several  sugars, 
from  which  lie  isolated  a  fermentaMe  sugar,  called  inelhoHc,  by  condensation  ol' 
formaldehyde  in  the  presence  of  bases.  The  most  important  and  comprehensive  syn- 
theses of  sugar  have  been  preformed  by  E.  Fischku.' 

Tliestartiiigpoiutof  these  syntheses  is  a-acrosc,  which  occuis  as  a  condensation  prod- 
uct of  formahlehyde.  The  name  <t-acrose  has  been  given  to  this  body  because  it  ia 
obtained  from  acrolein  bromide  by  the  action  of  bases  (Fischeu).  It  is  also  obtahied 
admixed  Avith  (i-acrom  on  the  oxidation  of  gl3'cerin  wilh  bioniine  in  the  presence  of 
sodium  carbonate,  and  treating  the  resulting  mixture  with  alkali.  On  the  oxidation  with 
bromine  a  mixture  of  glycerin  aldeliyde,  CIIa01I.C'II(0H).CII0  and  dioxyacetone, 
OHa(OH).CO.CHaOII,  is  obtained.  These  two  bodies  may  be  considered  as  true  sugar- 
glyceroses  or  trioses.  It  seems  as  if  a  condensation  to  hexoses  takes  place  on  treatment 
with  alkalies. 

rt-acrose  may  be  isolated  from  the  above  mixture  and  obtained  pure  by  first  convert- 
ing it  into  its  osazon  and  then  retransforming  this  into  the  sugar,  nr-acrose  is  identical 
with  i-levulose.  With  yeast  one  half,  the  hcvogyrate  d-levulose  ferments,  while  the  dex- 
trogyrate 1-levulose  remains.     The  i-  and  l-levulose  may  be  i)rei)i)red  in  this  wa}'. 

On  the  reduction  of  a-acrose  we  obtain  a-acrit,  which  is  identic:d  with  i-mnnnite. 
On  oxidation  of  i-mannite  we  obtain  i-mannose,  from  which  only  1-mannose  remains  on 
fermentation.  On  further  oxidation  of  i-manno.se  it  yields  i-mannonic  acid.  The  twa 
active  mannonic  acids  maybe  separated  from  each  other  by  the  frnctional  crystallization 
of  their  strychnin  or  morphin  salts.  The  two  corresponding  nuuinoses  may  be  obtained 
from  these  t.\o  acids,  d-  and  l-mannonic  acids,  by  reiiuction. 

d  levulose  is  obtained  from  d  niannose  by  the  method  given  on  page  74,  using  tho 
osazon  as  an  intermediate  step.  The  d-  and  l-mannonic  acids  are  partly  converted  into 
d-  and  1-gluconic  acid  on  heating  with  chinolin,  and  d-  or  1-glucose  is  obtained  on  tho 
reduction  of  these  acids.  1-glucose  is  best  prepared  from  l-arabinose  by  means  of  the 
cyanliydrin  reaction,  using  1-gluconic  acid  as  the  intermediate  step.  Tlie  combination 
of  1-  and  d-gluciinic  acid,  forming  i-gluconic  acid,  jields  iglucose  on  reduction. 

'I'he  artificial  preparation  of  sugars  by  means  of  condensation  of  formaldehyde  has 
received  special  interest  because,  according  to  Baeyek's  assimilation  hypothesis  of  plants, 
formaldehyde  is  first  formed  by  the  reducition  of  cari)on  dioxide,  aiul  the  sugars  are  pro- 
duced by  the  condensation  of  this  formaldehyde.  Bokokny  '  has  shown,  by  special  ex- 
jii'iiments  on  alga>  Spirogyra,  that  formaldehyde  sodium  sulphite  was  split  by  the  living 
alga'  cells.  The  formaldehyde  set  free  is  immediately  condensed  to  carbohydrate  and 
precipitated  as  starch. 

Among  the  hexoses  known  at  the  present  time  only  dextrose,  levulose, 
and  galactose  are  really  of  physiological  chemical  interest;  therefore  the 
other  hexoses  will  only  be  incidentally  mentioned. 

Dextrose  (d-glncose),  glycose,  grape-sugah,  and  diabetic  sugak, 
occurs  abundantly  in  the  grape,  and  also,  often  accompanied  with  levulose 
(d-fructose),  in  honey,  sweet  fruits,  seeds,  roots,  etc.  It  occurs  in  the 
intestinal  tract  during  digestion,  also  in  small  quantities  in  the  blood  and 
lymph,  and  as  traces  in  other  animal  fluids  and  tissues.  It  only  occurs  as 
traces  in  urine  nnder  normal  conditions,  while  in  diabetes  the  quantity  is 
very  large.     It  is  formed  in  the  hydrolytic  cleavage  of  starch,  dextrin,  and 

'  Butlerow,  Ann.  d.  Chem.  u.  Pharm.,  B.  120;  Compt.  rend.,  53;  O.  Loew,  Journ. 
f.  prakt.  Chem.  (N.  F.).  Bd.  33,  and  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  20,  21,  22. 
*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  21,  and  1.  c. ,  page  72,  this  book. 
»  Biolog.  Centralbl.,  Bd.  12,  S.  321  and  481. 


80  THE  CARB0ETDRATE8. 

other  compound  carbohydrates,  as  also  in  the  splitting  of  glucosides.  That 
dextrose  can  be  formed  from  proteids  in  the  animal  body  follows  from 
several  observations  and  especially  by  the  experience  in  severe  forms  of 
diabetes. 

Properties  of  Dextrose.  Dextrose  crystallizes  sometimes  with  1  mol. 
water  of  crystallization  ia  warty  masses  or  small  leaves  or  plates,  and  some- 
times when  free  from  Avater  in  needles.  The  sugar  containing  water  of 
crystallization  melts  even  below  100°  C.  and  loses  its  water  of  crystallization 
at  110°  C.  The  anhydrous  sugar  melts  at  146°  C,  and  is  converted  into 
glucosan,  C,H,t,Oj,  at  170°  C.  with  the  elimination  of  water.  On  strongly 
heating  it  is  converted  into  caramel  and  then  decomposed. 

Grape-sugar  is  readily  soluble  in  water.  This  solution,  which  is  not  as 
sweet  as  a  cane-sugar  solution  of  the  same  strength,  is  dextrogyrate  and 
shows  strong  birotation.  The  specific  rotation  is  somewhat  de|)endent  upon 
concentration  of  the  solution,  but  the  specific  rotation  of  a  watery  solution 
of  l-16fo  anhydrous  dextrose  at  -\-  20°  C.  may  be  considered  as  +  52°. 6. 
Dextrose  dissolves  sparingly  in  cold,  but  more  freely  in  boiling  alcohol. 
100  parts  alcohol  of  sp.  gr.  0.837  dissolves  1.95  parts  anhydrous  glucose  at 
-f- 1/°.  50.  aud  27.7  parts  at  the  boiling  temperature  (AxTHOiSr ').  Glucose 
is  insoluble  in  ether. 

lu  regard  to  the  modifications  of  dextrose,  their  solubilities  and  specific  rotation,  see 
Takret  (1.  c.) 

If  an  alcoholic  caustic-alkali  solution  is  added  to  an  alcoholic  solution  of 
glucose,  an  amorphous  jorecipitate  of  insoluble  alkali  compound  is  formed. 
On  warming  this  compound  it  decomposes  easily  with  the  formation  of  a 
yellow  or  brownish  color,  which  is  the  basis  of  Mooke's  test.  Dextrose 
forms  also  compounds  with  lime  and  baryta. 

Moore's  Test.  If  a  glucose  solution  is  treated  with  about  j  of  its 
volume  of  caustic  potash  or  soda  and  warmed,  the  solution  becomes  first 
yellow,  then  orange,  yellowish  brown,  and  lastly  dark  brown.  It  has  at  the 
same  time  a  faint  odor  of  caramel,  and  this  odor  is  more  pronounced  on 
acidification.' 

Glucose  forms  many  crystallizable  combinations  with  NaCl,  of  which 
the  easiest  to  obtain  is  (Cgll,.jOJj.XaCl  -f-  HjO,  which  forms  large  colorless 
•six-sided  doable  pyramids  or  rhomboids  with  13.40^  XaCl. 

Glucose  in  neutral  or  very  faintly  acid  (by  an  organic  acid)  solution 
passes  into  alcoholic  fermentation  with  beer-yeast,  CJI„0,  =  20,11^.011 
-j-  200,.  Besides  the  alcohol  and  carbon  dioxide  there  are  formed,  espe- 
cially  at   higher   temperatures,    small    quantities   of  homologous   alcohols 

'  Cited  from  Tollens'  Handbuch. 

'  In  regard  to  the  products  formed  in  this  reaction,  see  Pramm,  Pflliger's  Arch.,  Bd. 
64  and  especially  Gaud,  Compt.  rend.,  Tome  119. 


DEXTROSE.  81 

{amyl-alcoliol),  glycerin,  and  succinic  acid.  In  the  presence  of  acid  milk 
or  cheese  the  grape-sugar  passes,  especially  in  the  presence  of  a  base  such 
^3  ZnO,  or  CaC'O, ,  into  lactic-acid  fermentation.  The  lactic  acid  may  then 
further  pass  injto  butyric-acid  fermentation:  2C,II,0,  =  CJI^O, -f- 2C0, 
+  411. 

(;  rape-sugar  reduces  several  metallic  oxides,  such  as  copper  oxide 
bismuth  oxide,  mercuric  oxide,  in  alkaline  solutions,  and  the  most  impor- 
tant reactions  for  sugar  are  based  on  this  fact. 

Tkommer's  ted  is  based  on  the  property  that  glucose  possesses  of 
reducing  copper-hydrated  oxide  in  alkaline  solution  into  suboxide.  Treat 
the  glucose  solution  with  about  \-\  vol.  caustic  soda  and  then  carefully  add 
a  dilate  copper-sulphate  solution.  The  copper-hydrated  oxide  is  thereby 
dissolved,  forming  a  beautiful  blue  solution,  and  the  addition  of  copper 
sulphate  is  continued  until  a  very  small  amount  of  hydrate  remains  undis- 
solved in  the  liquid.  This  is  now  warmed  and  a  yellow  hydrated  suboxide 
or  red  suboxide  separates  even  below  the  boiling-point.  If  too  little  copper 
salt  has  been  added,  the  test  will  be  yellowish  brown  in  color  as  in  Moore's 
test;  but  if  an  excess  of  copper  salt  has  been  added,  the  excess  of  hydrate  is 
converted  on  boiling  into  a  dark-brown  hydrate  which  interferes  with  the 
test.  To  prevent  these  difficulties  the  so-called  Feiilixg's  solution  may  be 
employed.  This  reagent  is  obtained  by  mixing  before  use  equal  volumes  of 
an  alkaline  solution  of  Rochelle  salt  and  a  copper-sulphate  solution  (see 
Quantitative  Estimation  of  Sugar  in  the  Urine  in  regard  to  concentration). 
This  solution  is  not  reduced  or  noticeably  changed  by  boiling.  The  tartrate 
holds  the  excess  of  copper  oxyhydrate  in  solution,  and  an  excess  of  the 
reagent  does  not  interfere  in  the  performance  of  the  test.  In  the  presence 
of  sugar  this  solution  is  reduced. 

Bottger-Almex's  test  is  based  on  the  property  glucose  possesses  of 
reducing  bismuth  oxide  in  alkaline  solution.  The  reagent  best  adapted  for 
this  purpose  is  obtained,  according  to  Nylander's'  modification  of 
Almex's  original  test,  by  dissolving  4  grms.  Rochelle  salt  in  100  parts  10^ 
caustic-soda  solution  and  adding  2  grms.  bismuth  snbnitrate  and  digesting 
on  the  water-bath  until  as  much  of  the  bismuth  salt  is  dissolved  as  possible. 
If  a  glucose  solution  is  treated  with  about  -^^  vol.,  or  with  a  larger  quantity 
of  the  solution  when  large  quantities  of  sugar  are  jiresent,  and  boiled  for  a 
few  minutes,  the  solution  becomes  first  yellow,  then  yellowish  brown,  and 
lastly  nearly  black,  and  after  a  time  a  black  deposit  of  bismuth  (?)  settles. 

The  property  of  dextrose  of  reducing  an  alkaline  solution  of  mercury  on 
boiling  is  the  basis  of  Kxapp's  reaction  with  alkaline  mercuric  cyanide  and 
of  Sachsse's  reaction  with  an  alkaline  potassium-mercuric  iodide  solution. 

On  heating  with  phen'ylhydrazin  acetate  a  dextrose  solution  gives  a 

'  Zeitsohr.  f.  physiol.  Clicm.,  Bd.  8. 


82  TEE  CARBOHYDRATES. 

precipitate  consisting  of  fine  yellow  crystalline  needles  which  are  nearly 
insoluble  in  water  but  soluble  in  boiling  alcohol,  and  which  separate  again 
on  treating  the  alcoholic  solution  with  water.  The  crystalline  precipitate 
consists  of  plienylghicosazone.  This  componnd  melts  when  pure  at  20-i- 
205°  C. 

Glucose  is  not  precipitated  by  a  lead-acetate  solution,  but  is  almost 
completely  precij)itated  by  an  ammoniacal  basic  lead-acetate  solution.  On 
warming  the  precipitate  becomes  flesh-color  or  rose-red  (Rubber's 
reaction '). 

If  a  watery  solution  of  grape-sugar  is  treated  with  benzoyl-chloeide 
and  an  excess  of  caustic  soda,  and  shaken  until  the  odor  of  benzoylchloride 
has  disappeared,  a  precipitate  of  benzoic-acid  ester  of  glucose  will  be  pro- 
duced, which  is  insoluble  in  water  or  alkali  (Baumann'). 

If  \-l  c.c.  of  a  dilute  watery  solution  of  glucose  is  treated  with  a  few 

drops  of  a  15^  alcoholic  solution  of  a-naphthol,  the  liquid  is  colored  a. 

beautiful  violet  on   the  addition  of  1-2  c.c.  concentrated  sulphuric  acid 

(Molisch').     This  reaction  depends  on  the  formation  of  furfurol  from  the 

sugar  by  the  action  of  the  sulphuric  acid. 

Di/izoBENzoL-suLPHONio  ACID  givcs  with  a  dextrose  solution  made  alkaline  with  a 
fixed  alkali  a  red  color,  after  10-15  minutes  gradually  changing  to  violet.  Orthonitro- 
PHENYL-PROPiOLic  ACID  yields  indigo  when  boiled  with  a  small  quantity  of  sugar  and 
sodium  carbouale,  and  this  is  converted  into  iudigo-white  by  an  excess  of  sugar.  An 
alkaline  solution  of  grape-sugar  is  colored  deep  red  on  being  warmed  with  a  dilute  solu- 
tion of  PICRIC  ACID. 

A  more  complete  description  as  to  the  performance  of  these  several  tests 
will  be  given  in  detail  in  a  subsequent  chapter  (on  the  urine). 

Dextrose  is  prepared  pure  by  inverting  cane-sugar  by  the  following 
simple  method  of  Soxhlet  and  Tollens,  being  a  modification  of 
ScHWARz's '  method : 

Treat  12  litres  90^  alcohol  with  480  c.c.  fuming  hydrochloric  acid  and 
warm  to  45-50°  C. ;  gradually  add  4  kilos  powdered  cane-sugar,  and  allow , 
to  cool  after  2  hours,  when  all  the  sugar  will  have  dissolved  and  been 
inverted.  To  incite  crystallization,  some  crystals  of  anhydrous  dextrose  are 
added,  and  after  several  days  the  crystals  are  sucked  dry  by  the  air-pump, 
washed  with  dilute  alcohol  to  remove  hydrochloric  acid,  and  crystallized 
from  alcohol  or  methyl  alcohol.  According  to  Tollens  it  is  best  to  dissolve 
the  sugar  in  one  half  its  weight  of  water  on  the  water-bath  and  then  add 
double  this  volume  of  00-95^  alcohol. 

In  detecting  dextrose  in  animal  fluids  or  extracts  of  tissues  we  may 
make  use  of  the  above-mentioned  reduction  tests,  the  optical  determination, 

'  Zeitschr.  f.  Biologic,  Bd.  20. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  19  ;  also  Kueny,  Zeitschr.  f.  physiol.  Chem., 
Bd.  14. 

»  Monatshefte  f.  Chem.,  Bd.  7,  and  Centralbl.  f.  d.  med.  Wissensch.,  1887,  S.  34 
and  49. 

*  ToUeus'  Handbuch  der  Kohlehydrate,  2  Autl.,  S.  39. 


LEVULOSE.  85 

the  fermentation,  and  phenylhydrazin  tests.  For  the  quantitative  estima- 
tion the  reader  is  referred  to  the  cliapter  on  urine.  Those  liqnids  contain- 
ing proteids  must  first  have  these  removed  by  coagulation  w'th  heat  and 
addition  of  acetic  acid,  or  by  precipitation  with  alcohol  or  metallic  salts, 
before  testing  fol'  dextrose.  In  regard  to  the  difficulties  of  operating  with 
blood  and  serous  fluids  we  refer  the  student  to  the  works  of  Schenk^ 
lioiiMAXX,  AnKLES,  and  Seegen.' 

The  guloses  are  steieo-isomers  of  dextrose  and  may  be  prepared  artificially,  d-gulose 
is  obtained  on  the  reduction  of  d-gulouic  acid,  which  is  derived  on  the  reduction  of 
ulycmonic  acid  (see  cliapter  on  uriue). 

Mannoses. — dvwnnose,  also  called  seminose,  is  obtained  with  d-levulose,  on  the  careful 
oxidation  of  d-inaiinite.  It  is  also  obtained  on  the  hydrolysis  of  natural  carboh3-drales. 
such  !is  sale])  slime,  and  reserve  cellulose  (especially  from  the  shavings  from  tbe  ivory- 
nut).  It  is  dextrorotatory,  readily  ferments  with  beer-yeast,  gives  a  hydrazon  not  readily 
soluble  in  water,  and  an  osazon  which  is  identical  with  that  from  d-gliicose. 

LevuloBe,  also  called  d-fructose,  fruit-sugar,  occurs,  as  above  stated, 
mixed  with  dextrose  extensively  distributed  in  the  plant  kingdom  and  also 
in  honey.  It  is  formed  in  the  hydrolytic  cleavage  of  cane-sugar  and  other 
carbohydrates,  but  it  is  readily  obtained  by  the  hydrolytic  splitting  of 
inulin.  In  extraordinary  cases  of  diabetes  mellitus  we  find  levulose  in  the 
urine.  This  sugar  has  won  special  dietetic  importance  in  diabetes  on 
account  of  its  being  readily  assimilated.  ^ 

Levulose  crystallizes  with  difficulty  in  needles  partly  anhydrous  and 
partly  containing  water.  It  is  readily  soluble  in  water,  but  nearly  insoluble 
in  cold  absolute  alcohol,  though  rather  readily  in  boiling  alcohol.  Its 
■watery  solution  is  Irevogyrate,  but  the  statements  in  regard  to  the  specific 
rotation  are  quite  variable.  Levulose  ferments  with  yeast,  and  gives  the 
same  reduction  tests  as  dextrose  and  also  the  same  osazone.  It  gives  a 
combination  with  lime  which  is  less  soluble  than  the  corresponding  dextrose 
combination.  Levulose  is  not  precipitated  by  sugar  of  lead  or  basic  lead 
acetate. 

Levulose  does  not  reduce  copper  to  the  same  extent  as  dextrose.  Under 
similar  conditions  the  reduction  relationship  of  dextrose  to  levulose  is 
100  :  92.08. 

In  detecting  levulose  and  those  varieties  of  sugar  which  yield  levulose 
on  cleavage  we  make  use  of  the  following  reaction  suggested  by  Sei.i- 
WANOFF.  Quickly  warm  a  solution  of  resorcin  in  medium  dilute  hydro- 
chloric acid  with  levulose  when  the  liquid  becomes  beautifully  red  and  a 
precipitate  settles  which  dissolves  in  alcohol  with  a  beautiful  red  color. 
Use  a  mixture  of  1  vol.  hydrochloric  acid  and  2  vols,  water. 

Fructose,  as  above  stated,  is  best  obtained  by  the  hydrolytic  cleavage  ot 

inulin,  by  warming  with  faintly  acidalated  water. 

Sorbinose  (sorbin)  is  obtained  from  the  juice  of  the  berry  of  the  mountain  ash  under 
certain  conditions.  It  is  crystalline  and  is  laevogyrate,  and  is  converted  into  sorbit  by 
reduction  ;  hence  it  seems  to  be  a  ketose  which  is  stereo-isomeric  with  fructose. 

'  Schenck,  PQiiger's  Arch.,  Bd<i.  46  and  47;  Rfthmann,  Centralbl.  f.  Physiol.,  Bd.  4; 
Abeles,  Zeitschr.  f.  physiol.  Clieni.,  Bd.  15  :  Seegcn,  Ceutralbl.  f.  Physiol.,  Bd.  4. 


M  THE   CABBOUYDRATES. 

Galactose  (not  to  be  mistaken  for  lactose  or  milk-sugar)  is  obtaiued  on 
the  hydrolytic  cleavage  of  milk-sugar  and  by  hydrolysis  of  many  other 
carbohydrates,  especially  varieties  of  gums  and  slime  bodies.  It  is  also 
obtained  on  heating  cerebrin,  a  nitrogenized  glacoside  prepared  from  the 
brain,  with  dilate  mineral  acids. 

It  crystallizes  in  needles  or  leaves,  which  melt  at  168°  C.  It  is  some- 
what less  soluble  than  dextrose  in  water.  It  is  dextrogyrate,  and  shows 
mnltirotation.  It  ferments  with  yeast,  although  slowly.  It  is  fermented 
by  a  large  nnmber  of  varieties  of  yeast  (E.  Fischer  and  Thierfelder) 
but  not  by  saccharomyces  apicnlatns,'  which  is  of  importance  in  physio- 
logical chemical  investigations.  Galactose  reduces  Fehlikg's  solution  to  a 
less  extent  than  dextrose,  and  10  c.c.  of  this  solution  are  reduced,  according 
to  Soxhlet,  by  0.0511  gm.  galactose  ia  Ifo  solution.  Its  phenylosazon 
melts  at  193°  C,  and  is  soluble  with  difficulty  in  water,  but  relatively  easy 
in  hot  alcohol.  Its  solution  in  glacial  acetic  acid  is  optically  inactive. 
With  the  test  with  hydrochloric  acid  and  phloroglucin  galactose  gives  a 
color  similar  to  the  pentoses,  but  the  solution  does  not  give  the  absorption 
spectrum.  On  oxidation  it  first  yields  galactonic  acid  and  then  mucic  acid. 
Both  1-  and  i-galactose  have  been  artificially  prepared. 

Talose  is  a  sugar  •whicli  is  artificially  prepared  by  the  reduction  of  talonic  acid. 
Talonic  acid  is  obtained  from  d-galactouic  acid  by  heating  it  witli  chinolin  or  pyridiu  to 
140-150°  C. 

Disaccliarides. 

Some  of  the  varieties  of  sugar  belonging  to  this  group  occur  ready 
formed  in  nature.  Thus  we  have  cane-sugar  and  milk-sngar.  Some,  on 
the  contrary,  such  as  maltose  and  isomaltose,  are  produced  by  the  partial 
hydrolytic  cleavage  of  complicated  carbohydrates.  Isomaltose  is  besides 
this  also  obtained  from  glucose  by  reversion  (see  below). 

The  disaccharides  or  hexobioses  are  to  be  considered  as  anhydrides, 
derived  from  two  monosaccharides  with  the  exit  of  1  mol.  water.  Corre- 
sponding to  this,  their  general  formula  is  Cj^H^^O^.  On  hydrolytic 
cleavage,  on  the  addition  of  water,  they  yield  two  molecules  of  hexoses,  and 
indeed  either  two  molecules  of  the  same  hexose  or  two  different  hexoses. 
Thus: 

Cane-sugar  -|-  H,0  ■=  glucose  +  levulose; 

Maltose        -(-  11,0  =  glucose  +  glucose; 

Milk-sugar  -(-  11,^0  =  glucose  +  galactose. 

The  levulose  turns  the  polarized  ray  more  to  the  left  than  the  glucose 
does  to  the  right;  hence  the  mixture  of  hexoses  obtained  on  the  cleavage  of 
cane-sugar  lias  an  opposite  rotation  to  the  cane-sugar  itself.  On  this 
Account  the  mixture  is  called  invert  sugar,  and  the  hydrolytic  splitting 

'  See  F.  Voit,  Zeitscbr.  f.  Biologie,  Bdd.  28  and  29. 


CANE-SUGAli  AND   MALTOSE.  85 

is  designated  as  inversion.  Tiiis  term  inversion  is  not  only  used  for  tlie 
splitting  of  cane-sugar,  but  is  also  used  for  tlie  hydrolytic  cleavage  of 
compound  sugars  into  monosaccharides.  The  reverse  reaction,  whereby 
monosaccharidea  are  condensed  into  complicated  carbohydrates,  is  called 
reversion.  A.  C.  Hill'  has  shown  that  the  cleavage  of  maltose  by  the 
enzyme  maltase  is  a  convertible  process  as  a  sugar  formation  of  maltose 
from  glucose  takes  place. 

AYe  subdivide  the  disaccharides  into  two  groups.  One,  to  which  cane- 
sugar  belongs,  where  the  members  have  not  the  property  of  reducing  certain 
metallic  oxides.  The  other  group,  on  the  contrary,  to  which  the  two 
maltoses  and  milk-sugar  belong,  the  members  act  like  monosaccharides  in 
regard  to  the  ordinary  reduction  tests.  The  members  of  this  last  group 
have  the  character  of  aldehyde-alcohols. 

Cane-sugar  or  Saccuarose  occurs  extensively  distributed  in  the  plant 
kingdom.  It  occurs  to  greatest  extent  in  the  stalk  of  the  sugar-millet  and 
sugar-cane,  the  roots  of  the  sugar-beet,  the  trunk  of  certain  varieties  of 
palms  and  maples,  in  carrots,  etc.  Cane-sugar  is  of  extraordinarily  great 
importance  as  a  food  and  condiment. 

Cane-sugar  forms  large,  colorless  monoclinic  crystals.  On  heating  it 
melts  in  the  neighborhood  of  100°  C,  and  on  heating  stronger  it  turns 
brown,  forming  so-called  caramel.  It  dissolves  very  readily  in  water,  and 
according  to  Sciieibler'  100  parts  saturated  sugar  solution  contains  67 
parts  sugar  at  20°  C.  It  dissolves  with  difficulty  in  strong  alcohol.  Cane- 
sugar  is  strongly  dextro-rotatory.  The  specific  rotation  is  only  slightly 
modified  by  concentration,  but  is  markedly  changed  by  the  presence  of 
other  inactive  substances.     The  specific  rotation  is  {a)D=  +  GG°.5. 

Cane-sugar  acts  indifferently  towards  Moore's  test  and  to  the  ordinary 
reduction  tests.  It  does  not  ferment  directly,  but  ferments  after  inversion, 
which  can  be  brought  about  by  an  enzym,  invertin,  contained  in  the  yeast. 
An  inversion  of  cane-sugar  also  takes  place  in  the  intestinal  canal.  Con- 
centrated sulphuric  acid  blackens  cane-sugar  very  quickly  even  at  the 
ordinary  temperature,  and  anhydrous  oxalic  acid  acts  the  same  on  warming 
on  the  water-bath.  Various  products  are  obtained  on  the  oxidation  of 
cane-sugar,  dependent  upon  the  variety  of  oxidizing  material  and  also  upon 
the  intensity  of  the  action.  Saccharic  acid  and  oxalic  acid  are  the  most 
important   products. 

The  reader  is  referred  to  complete  text-books  on  chemistry  for  the 
preparation  and  quantitative  estimation  of  cane-sugar. 

Maltose  (malt-sugar)  is  formed  in  the  hydrolytic  cleavage  of  starch  by 
malt  diastase,  saliva,  and  pancreatic  juice.     It  is  obtained  from  glycogen. 

'  Trausact.  of  Cliein.  Soc,  1898. 

»  See  Tolleus'  Haudbuch  dor  Kolilehydrale.  2  Aufl  ,  S.  124. 


S6  THE  CABBOHJDRATES. 

Tinder  the  same  conditions  (see  Chapter  YIII).  Maltose  is  also  produced 
transitorily  in  the  action  of  sulphuric  acid  on  starch.  Maltose  forms  the 
fermentable  sugar  of  the  potato  or  grain  mash,  and  also  of  the  beerwort. 
It  does  not  ferment  directly,  but  only  after  inversion,  and  this  is  brought 
about  by  a  special  invertin,  maltase,  occurring  in  the  yeast-cell. 

Maltose  crystallizes  with  1  mol.  water  of  crystallization  in  fine  white 
needles.  It  is  readily  solnble  in  water,  rather  easily  in  alcohol,  but  insolu- 
ble in  ether.  Its  solutions  are  dextro-rotatory,  and  show  birotation.  The 
specific  rotation  is  (a)D  =  +  137°.  Maltose  ferments  readily  and  com- 
pletely with  yeast,  and  acts  like  dextrose  in  regard  to  the  reduction  tests. 
It  yields  phenylmaltosazone  on  warming  with  phenylhydrazin  for  1^  hours. 
This  phenylmaltosazone  melts  at  206°  C.  and  is  more  soluble  than  the 
glucosazone.  Maltose  differs  from  dextrose  chiefly  in  the  following:  It  does 
not  dissolve  as  readily  in  alcohol,  has  a  stronger  dextro-rotatory  power,  has  a 
feebler  reducing  action  on  Feeling's  solution.  10  c.c.  Fehling's  solu- 
tion is,  according  to  Soxhlet,'  reduced  by  77.8  milligrams  anhydrous 
maltose  in  approximately  Ifo  solution. 

Isomaltose.  This  variety  of  sugar  is  produced,  as  has  been  shown  by 
Fischer,'  besides  dextrin-like  products,  by  the  action  of  fuming  hydrochloric 
acid  on  glucose.  It  is  also  formed,  besides  ordinary  maltose,  in  the  action 
of  diastase  on  starch  paste,  and  occurs  in  beer  and  in  commercial  starch-sugar.' 
The  formation  of  isomaltose  in  the  hydrolysis  of  starch  by  malt  diastase  has 
been  denied  by  many  investigators  because  they  considered  isomaltose  as 
contaminated  maltose.*  It  is  also  produced,  with  maltose,  by  the  action  of 
saliva  or  pancreatic  juice  (Kulz  and  Vogel)  or  blood-serum  (Rohmann  ') 
on  starch. 

Isomaltose  dissolves  very  readily  in  water,  has  a  pronounced  sweetish 
taste  and  does  not  ferment,  or,  according  to  some,  only  very  slowly.  It  is 
dextro-rotatory,  and  has  very  nearly  the  same  power  of  rotation  as  maltose. 
Isomaltose  is  characterized  by  its  osazone.  This  forms  fine  yellow  needles, 
which  begin  to  form  drops  at  140°  C.  and  melt  at  150-153°  C.  It  is 
rather  easily  solnble  in  hot  water  and  dissolves  in  hot  absolute  alcohol  much 
more  readily  than  the  maltosazon.  Isomaltose  reduces  copper  as  well  as 
bismuth  solutions. 


'  Cited  from  Tollens'  Handbuch  der  Kohlenliydrate,  2  Anil.,  S.  154. 

'  Ber.  d.  deutsch.  clieni.  GcBellscli.,  Bdd.  23  and  28. 

»  See  Lintner  and  Dull,  ibid.,  Bd.  26,  S.  2533  ;  Scheibkr  and  Miltelmeier,  ibid.,  Bd. 
24,  S.  301. 

■»  Brown  and  Morris,  Journ.  of  Cliem.  Soc,  1895,  Chcm.  News,  72;  see  also  Ost, 
Ulrich,  and  Jalowetz,  Ref.  in  Ber.  d.  deutsch.  chem.  Gcsellscb.,  Bd.  28,  S.  987-989; 
Ling  and  Baker,  Journ.  of  Chem.  Soc,  1895. 

'  Kiilz  and  Vogel,  Zeitscbr.  f.  Biologic,  Bd.  31  ;  RObmann,  Centralbl.  f.  d.  mod. 
TVissenscb..  1893.  S.  849. 


STARCH.  87 

Milk-sugar  (lactose).     As  this  sngar  occurs  exclusively  in  the  animal 

"world,  in  the  milk  of  human  beings  and  animals,  it  will  be  treated  of  in  a 

following  chapter  (on  milk). 

Trehalose  is  ii  bcxobiose  found  in  fungi.  Melebiose  is  u  succbarose  obtained  with 
d-fnictose  in  the  partial  bydrolytic  cleavage  of  raffinose  (a  hexotriose)  occurring  in  licet- 
roul  molasses.     Melebiose  splits  into  galactose  and  glucose. 

Polysaccharides. 

If  we  exclude  the  hexotrioses  and  tlie  few  remaining  sugar-like  poly- 
saccharides, this  group  includes  a  great  number  of  very  complex  carbo- 
hydrates, which  occur  only  in  the  amorphous  condition  or  not  as  crystals  in 
the  ordinary  sense.  Unlike  the  bodies  belonging  to  the  other  groups, 
these  have  no  sweet  taste.  Some  are  soluble  in  water,  while  others  swell 
u})  therein,  especially  in  warm  water,  and  finally  are  neither  dissolved  nor 
visibly  changed.  Polysaccharides  are  ultimately  converted  into  monosac- 
charides by  hydrolytic  cleavage. 

The  jjolysaccharides  (not  sugar-like)  are  ordinarily  divided  into  the 
following  chief  groups:  starch  group,  gum  and  vegetable-mucilage  group, 
and  cellulose  group. 

Starch  Group  (C.ll,„0.)x. 

Starch,  Amylum.  (CgH,„OJx.  This  substance  occurs  in  the  plant 
kingdom  very  extensively  distributed  in  the  different  parts  of  the  plant, 
especially  as  reserve  food  in  the  seeds,  roots,  tubers,  and  trunk. 

Starch  is  a  white,  odorless,  and  tasteless  powder,  consisting  of  small 
grains,  which  have  a  stratified  structure  and  different  shape  and  size  in 
different  plants.  According  to  the  ordinary  opinion  the  starch-grains  con- 
sist of  two  different  substances,  starch  graxulose  and  starch  cellu- 
lose, of  which  the  first  only  goes  into  solution  on  treatment  with  diastatic 
enzymes. 

Starch  is  considered  insoluble  in  cold  water.  The  grains  swell  up  in 
■warm  water  and  burst,  yielding  a  paste.  Starch  is  insoluble  in  alcohol  and 
ether.  On  heating  starch  with  water  alone,  or  heating  with  glycerin  to 
190°  C,  or  on  treating  the  starch-grains  with  G  parts  dilute  hydrochloric 
acid  of  sp.  gr.  l.OG  at  ordinary  temperature  for  G  to  8  weeks,'  it  is  con- 
verted into  soluble  starch  (amylodextrix,  amidulix).  Soluble  starch  is 
also  formed  as  an  intermediate  step  in  the  conversion  of  starch  into  sugar  by 
dilute  acids  or  diastatic  enzymes.  Soluble  starch  may  be  precipitated  from 
very  dilute  solutions  by  baryta- water.' 

Starch-granules  swell  irp  and  form  a  pasty  mass  in  caustic  potash  or 

'  See  Tollens'  Handb.,  S.  191.  In  regard  to  other  methods,  see  Wroblewski,  Ber.  d. 
deutsch.  chem.  Gesellsch.,  Bd.  30;  Syniewski,  ibid. 

'  In  regard  to  the  combinations  of  soluble  starch  and  dextrins  with  barium  hydrate, 
see  Biilow,  Ptliiger's  Arch.,  62. 


yS  THE  CARBOHYDRATES. 

soda.  This  mass  gives  neither  Moore's  nor  Thommer's  test.  Starch- 
paste  does  not  ferment  with  yeast.  The  most  characteristic  test  for  starch 
is  the  blue  coloration  produced  by  iodine  in  the  presence  of  hydroiodic  acid 
or  alkali  iodides.'  This  blue  coloration  disaj^pears  on  the  addition  of 
alcohol  or  alkalies,  and  also  on  warming,  bat  reappears  again  on  cooling. 

On  boiling  with  dilute  acids  starch  is  converted  into  glucose.  In  the 
conversion  by  means  of  diastatic  enzymes  we  have  as  a  rule,  besides  dextrin, 
maltose,  and  isoraaltose,  only  very  little  glucose.  We  are  considerably  in 
the  dark  as  to  the  kind  and  number  of  intermediate  products  produced  in 
this  process  (see  dextrins). 

Starch  may  be  detected  by  means  of  the  microscope  and  by  the  iodine 
reaction.  Starch  is  quantitatively  estimated,  according  to  Sachsse's 
method,^  by  converting  it  into  sugar  by  hydrochloric  acid  and  then  deter- 
mining the  sugar  by  the  ordinary  methods. 

Inulin,  (CgHj„OJx  +  H^O,  occurs  in  the  underground  parts  of  many 
composite,  especially  in  the  roots  of  the  inula  helenium,  the  tubers  of  the 
dahlia,  the  varieties  of  helianthus,  etc.  It  is  ordinarily  obtained  from  the 
tubers  of  the  dahlia. 

Inulin  forms  a  white  powder,  similar  to  starch,  consisting  of  spha^roid 
crystals,  which  are  readily  soluble  in  warm  water  without  forming  a  paste. 
It  separates  slowly  on  cooling,  but  more  rapidly  on  freezing.  Its  solutions 
are  Ifevogyrate  and  are  precipitated  by  alcohol,  and  are  only  colored  yellow 
with  iodine.  Inulin  is  converted  into  the  l^vogyrate  monosaccharide 
levulose,  on  boiling  with  dilate  sulphuric  acid.  Diastatic  enzymes  have  no 
or  very  slight  action  on  inulin.' 

Lichenin  (moss  stakch)  occurs  in  many  lichens,  namely,  in  Iceland  moss.  It  is  not 
soluble  in  cold  water,  but  swells  up  into  a  jelly.  It  is  soluble  in  hot  water,  forming  a 
jelly  on  allowing  tbe  concentrated  solution  to  cool.  It  is  colored  yellow  by  iodine,  and 
yields  glucose  on  boiling  with  dilute  acids.  Licheuin  is  not  changed  by  diastatic  enzymes 
such  us  ptyaliu  or  amylopsin  (Nii.soN*). 

Glycogen.  This  carbohydrate,  which  stands  to  a  certain  extent  between 
starch  and  dextrin,  is  principally  found  in  the  animal  kingdom,  hence  it 
will  be  treated  in  a  subsequent  chapter  (on  the  liver). 

The  Gums  and  Vegetable  Mucilages  (C,H,„OJx. 

These  bodies  may  be  divided  into  two  chief  groups,  according  to  their 
origin  and  occurrence,  namely,  the  dextrin  groiq)  and  the  veoetable  guyns  or 
mucilages.  The  dextrins  stand  in  close  relationship  to  the  starches  and  are 
formed    therefrom   as  intermediate  products  in  the  action  of   acids  and 


>  Sec  Mylius,  Bcr.  d.  deutscli.  chem.  Gesellsch.,  Bd.   20,  and  Zeitschr.  f.   pbysiol. 
Cbem.,  Bd.  11. 

»  Tolleu.s'  Ilandb.,  2  Aufl.,  S.  187. 

*  Ibid.,  S.  208. 

*  Upsala  Lakaref.  F&rh.,  28. 


DEXTRINS.  89 

diastatic  enzymes.  The  various  kinds  of  vegetable  gnms  and  vegetable 
mucilages  occur,  on  the  contrary,  as  natural  products  in  the  plant  kingdom, 
and  some  may  be  separated  from  certain  i)lants  as  amorplious,  transparent 
masses  and  others  may  be  extracted  from  certain  parts  of  the  plant,  such  as 
the  wood  and  seeds,  by  proper  solvents. 

Tlie  dextrins  yield  as  final  products  only  hexoses,  and  indeed  onix 
dextrose  on  complete  hydrolysis.  The  vegetable  gums  and  the  mucilages 
yield,  on  the  contrary,  not  oidy  hexoses,  but  also  an  abundance  of  pentoses 
(gum  urabic  and  wood-gum),  d-galactose  occurs  often  amongst  the  hexoses, 
and  as  dillerentiation  from  the  dextrins  they  yield  mucic  acid  on  oxidation 
with  nitric  acid.  The  dextrins,  as  well  as  the  ordinary  varieties  of  gums 
and  mucilages,  are  i)reci2Mtated  by  alcohol.  Basic  lead  acetate  precipitates 
the  gums  and  mucilages,  but  not  the  dextrins. 

Dextrin  (British  gum)  is  produced  on  heating  starch  to  200-210°  C, 
or  by  heating  starch,  which  has  i)revionsly  been  moistened  with  water 
containing  a  little  nitric  acid,  to  100-110°  C.  Dextrins  are  also  i)rodnced 
by  the  action  of  dilute  acids  and  diastatic  enzymes  on  starch.  We  are  not 
quite  clear  in  regard  to  the  steps  taking  place  in  the  above  processes,  but 
the  ordinary  views  are  as  follows:  Soluble  starch  is  the  first  product,  from 
which  a  dextrin,  eri/(Jtrode.iirin,  which  is  colored  red  by  iodine,  and  sugar 
are  formed  by  hydrolytic  splitting.  On  further  cleavage  of  this  erythro- 
dextrin  more  sugar  and  a  dextrin,  achroodextri/i,  which  is  not  colored  by 
iodine,  is  formed.  From  this  achroodextrin  after  successive  splittings  we 
have  sugar  and  dextrins  of  lower  molecular  Aveights  formed,  until  finally  we 
have  sugar  and  a  dextrin,  maliodextrin,  which  refuses  to  split  further,  as 
final  products.  The  views  are  rather  contradictory  in  regard  to  the  number 
of  dextrins  which  occur  as  intermediate  steps.  The  sugar  formed  is 
isomaltose,  from  which  maltose  and  only  very  little  dextrose  are  produced. 
Another  view  is  tliat  first  several  dextrins  are  formed  consecutively  in  the 
successive  splitting  with  hydration,  and  then  finally  the  sugar  is  formed  by 
the  splitting  of  the  last  dextrin.  Other  investigators  have  other  views  in 
regard  to  this  jirocess.' 

The  various  dextrins  have  not  as  yet  been  separated  from  each  other, 
nor  isolated  as  chemical  individuals.  Recently  Young  '  has  tried  their 
separation  by  means  of  neutral  salts,  especially  ammonium  sulphate.  We 
cannot  enter  into  the  differences  as  to  the  dextrins  so  separated,  and  only 
the  characteristic  properties  and  reactions  will  be  given  for  the  dextrins  in 
general. 

'  lu  regard  to  tbe  various  views  ou  the  theories  of  the  saccharificution  of  Starch,  see 
Musculus  and  Gruber,  Zeitschr.  f.  physiol.  Chem.,  Bd.  2,  S.  177;  Lintuer  and  Dull, 
1.  c,  Bdd.  26  and  28;  Billow,  1.  c;  Brown  and  Heron,  Journ.  of  chem.  Soc,  1879; 
Brown  and  Morris,  ibid.,  188    and  1889. 

*  Journ.  of  Physiol.,  Vol.  22,  which  contains  the  older  researches  of  Nasse,  Kriiger, 
Xeumeister,  Pohl,  and  Ualliburton  on  the  precipitation  of  carbohydrate  by  salts. 


90  THE  CARB0HTDRATE8. 

The  dextrins  appear  as  an  amorphous,  white  or  yellowish-white  powder 
which  is  readily  soluble  in  water.  Their  concentrated  solutions  are  viscid 
and  sticky,  similar  to  gum  solutions.  The  dextrins  are  dextrogyrate. 
They  are  insoluble  or  nearly  so  in  alcohol,  and  insoluble  in  ether.  Watery 
solutions  of  dextrins  are  not  precipitated  by  basic  lead  acetate.  Dextrins 
dissolve  copper  oxy hydrate  in  alkaline  liquids,  forming  a  beautiful  blue 
solution.  The  question  whether  or  not  perfectly  pure  dextrin  reduces 
FEnLi]srG's  solution  is  undecided.  According  to  Brucke'  a  non-reducible 
dextrin  may  be  obtained  by  warming  a  solution  of  achroodextrin  with  an 
excess  of  alkaline  copper  solution  and  then  precipitating  with  alcohol. 
According  to  Scheibler  and  Mittelmeier  °  the  dextrin  obtained  by  the 
action  of  acid  is  a  polysaccharide  of  an  aldehydic  nature,  hence  it  acts  as  a 
reducing  agent.  The  dextrins  are  not  directly  fermentable.  The  behavior 
of  the  various  dextrins  to  iodine  has  been  given  above,  but  it  must  be 
remarked  that,  according  to  MuscuLUS  and  Meter,^  erythrodextrin  is  only 
a  mixture  of  achroodextrin  with  a  little  soluble  starch. 

The  vegetable  gums  are  soluble  in  water,  forming  solutions  which  are 
viscid/ bat  may  be  filtered.  We  designate,  on  the  contrary,  as  vegetable 
mucilages  those  varieties  of  gum  which  do  not  or  only  partly  dissolve  in 
water,  and  which  swell  up  therein  to  a  greater  or  less  extent.  The  natural 
varieties  of  gum  and  macilage  to  which  several  generally  known  and  im- 
portant substances,  such  as  gum  arabic,  wood-gum,  cherry-gum,  salep,  and 
quince  mucilage,  and  probably  also  the  little-studied  pectin  substances, 
belong  will  not  be  treated  of  in  detail,  because  of  their  unimportance  from 
a  zoo-physiological  standpoint. 

The  Cellulose  Group  (C„H,„OJx. 

Cellulose  is  that  carbohydrate,  or  perhaps  more  correctly  mixture  of 
carbohydrates,  which  forms  the  chief  constituent  of  the  walls  of  the  plant- 
cells.  This  is  true  for  at  least  the  walls  of  the  young  cells,  while  in  the 
walls  of  the  older  cells  the  cellulose  is  extensively  incrusted  with  a  substance 
called  LiGNiN. 

The  true  celluloses  are  characterized  by  their  great  insolubility.  They 
are  insoluble  in  cold  or  hot  water,  alcohol,  ether,  dilute  acids,  and  alkalies. 
We  have  only  one  specific  solvent  for  cellulose,  and  that  is  an  ammoniacal 
solution  of  copper  oxide  called  Schweitzer's  reagent.  The  cellulose  may 
be  precipitated  from  this  solvent  by  the  addition  of  acids,  and  obtained  as 
an  amorphous  powder  after  washing  with  water. 

Cellulose  is  converted  into  a  substance,  so-called  amyloid,  which  gives 

1  Vorlesungen  ttber  Physiologie,  Wien,  1874,  S.  231, 
'  Ber.  d.  deutsch.  cbeni,  Gesellscli.,  Bd.  23. 
'  Zeitsch.  f.  physiol.  Chem.,  Bd.  4,  S.  451. 


CELLULOSE.  91 

a  bine  coloration  with  iodine  by  the  action  of  concentrated  salplmric  acid. 
By  the  action  of  strong  nitric  acid  or  a  mixture  of  nitric  acid  and  concen- 
trated sulphuric-acid  celluloses  are  converted  into  nitric-acid  esters  or  nitro- 
celluloses,  which  are  highly  explosive  and  have  found  great  practical  nse. 

The  ordinary  celluloses  when  treated  at  the  ordinary  temperature  with 
strong  sulphuric  acid  and  then  boiled  for  some  time  after  diluting  with 
water  are  converted  into  dextrose.  Other  varieties  of  cellulose  have  a 
different  behavior,  namely,  we  have  a  cellulose  which  on  account  of  its 
insolubility  in  hot  dilute  mineral  acids  stands  close  to  ordinary  cellulose, 
which  yields  mannose  on  the  preceding  treatment.  This  substance  called 
mannose-cellulose  by  E,  Sciiulze,  occurs  in  the  coffee-bean,  as  well  as  in 
the  cocoanut  and  sesame  cake. 

Hemicelluloses  are,  according  to  E.  Schulze,  those  constituents  of  the 
cell-wall  related  to  cellulose  which  differ  from  the  ordinary  cellulose  by 
dissolving  on  heating  with  strongly  diluted  mineral  acids,  such  as  1,25,'^ 
sulphuric  acid,  with  a  splitting  into  monosaccharides.  The  sugars  produced 
hereby  are  of  different  kinds.  The  hemicellulose  from  the  yellow  lupin 
yields  galactose  and  arabiuose,  from  the  rye  and  wheat  bran  arabinose  and 
xylose,  and  from  the  ivory-nut — called  reserve  cellulose  by  Reiss  ' — 
mannose.  Schulze  '  has  recently  suggested  to  designate  as  cellulose  only 
the  dextrose-celluloses — namely,  only  those  which  can  be  transformed  into 
dextrose.  All  other  celluloses  and  also  the  mannose-cellulose  must  then  be 
called  hemicelluloses. 

The  cellulose,  at  least  in  part,  undergoes  decomposition  in  the  intestinal 
tract  of  man  and  animals.  A  closer  discussion  of  the  nutritive  value  of 
cellulose  will  be  given  in  a  future  chapter  (on  digestion).  The  great  im- 
portance of  the  carbohydrates  in  the  animal  economy  and  to  animal  meta- 
bolism will  also  be  given  in  following  chapters. 

■  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  22. 
« Zeitschr.  f.  physlol.  Chem.,  Bdd.  16  and  19. 


CHAPTEE  lY. 

THE   ANIMAL  FATS. 

The  fats  form  the  third  chief  groujo  of  the  organic  foods  of  man  and 
animals.  They  occur  very  widely  distributed  in  the  animal  and  plant 
kingdoms.  Fat  occurs  in  all  organs  and  tissues  of  the  animal  organism, 
though  the  quantity  may  he  so  variable  that  a  tabular  exhibit  of  the  amount 
of  fat  in  different  organs  is  of  little  interest.  The  marrow  contains  the 
largest  quantity,  having  over  960  p.  m.  The  three  most  important  deposits 
of  fat  in  the  animal  organism  are  the  intermuscular  connective  tissae,  the 
fatty  tissue  in  the  abdominal  cavity,  and  the  subcutaneous  connective- 
tissues.  Amongst  the  plants  the  seeds  and  fruit,  and  in  certain  instances 
also  the  roots,  are  rich  in  fat. 

The  fats  consist  nearly  entirely  of  so-called  neutral  fats  with  only  very 
small  quantities  of  fatty  acids.  The  neutral  fats  are  esters  of  the  triatomic 
alcohol,  glycerin,  with  monobasic  fatty  acids.  These  esters  are  triglyc- 
erides, that  is,  the  three  hydrogen  atoms  of  the  hydroxyl  of  the  glycerin 
are  replaced  by  the  fatty-acid  radicals,  and  their  general  formula  is  there- 
fore C,H,.03.R3.  The  animal  fats  consist  chiefly  of  esters  of  the  three  fatty 
acids,  stearic,  palmitic,  and  oleic  acids.  In  certain  fats,  especially  in  milk- 
fat  glycerides  of  fatty  acids  such  as  butyric,  caproic,  caprylic,  and  capric 
acids  also  occur  in  considerable  amounts.  Besides  the  above-mentioned 
ordinary  fatty  acids,  stearic,  palmitic,  and  oleic,  we  also  find  in  human  and 
animal  fat,  exclusive  of  certain  fatty  acids  only  little  studied,  the  following 
non-volatile  fatty  acids,  as  glycerides,  lauric  acid,  C^Hj^O,,  myristic  acid, 
CjJI^gO^,  and  arachidic  acid,  C,„H,„0,.  In  the  plant  kingdom  triglycerides 
of  other  fatty  acids,  such  as  lauric  acid,  myristic  acid,  linoleic  acid,  erucic 
acid,  etc.,  sometimes  occur  abundantly.  Besides  these,  oxj^acids  and  high 
molecular  alcohols  have  been  found  in  many  animal  fats.  The  occurrence 
of  traces  of  these  oxyacids  has  not  been  positively  investigated.  The 
occurrence  of  high  molecular  alcohols,  although  ordinarily  only  in  small 
amounts,  has  on  the  contrary  been  positively  shown  in  animal  fat. 

The  animal  fats  are  of  the  greatest  interest  and  consist  of  a  mixture  of 
varying  quantities  of  tristearin,  tripalmitin,  and  triolein,  having  an 
average  elementary  composition  of  C  70. 5,  II  12.0,  and  0  11.5^. 

92 


NEUTRAL   FATS.  93 

Fats  from  different  species  of  animals,  and  even  from  different  parts  of 
the  same  animal,  liave  an  essentially  different  consistency,  depending  uj)on 
the  relative  amounts  of  the  different  fats.  In  solid  fats — as  tallow — 
tristearin  and  tripalmitin  are  in  excess,  while  the  less  solid  fats  are  charac- 
terized by  a  greater  abundance  of  tripalmitin  and  triolein.  This  last- 
mentioned  fat  is  found  in  greater  quantities  proportionally  in  cold-blooded 
animals,  and  this  accounts  for  the  fat  of  these  animals  remaining  fluid  at 
temperatures  at  whicli  the  fat  of  warm-blooded  animals  solidifies.  Human 
fat  from  different  organs  and  tissues  contains,  in  round  numbers,  G70-800 
p.  m.  triolein.'  The  melting-point  of  different  fats  depends  upon  the  com.- 
position  of  the  mixtures,  and  it  not  only  va,ries  for  fat  from  different  tissues 
of  the  same  animal,  but  also  for  the  fat  from  the  same  tissues  in  various 
kinds  of  animals. 

Neutral  fats  are  colorless  or  yellowish  and,  when  perfectly  pure,  odorless 
and  tasteless.  They  are  lighter  than  water,  on  which  they  float  when  in  a 
molten  condition.  They  are  insoluble  in  water,  dissolve  in  boiling  alcohol, 
but  separate  on  cooling, — often  in  crystals.  They  are  easily  soluble  in 
ether,  benzol,  and  chloroform.  The  fluid  neutral  fats  give  an  emulsion 
when  shaken  with  a  solution  of  gum  or  albumin.  "With  water  alone  they 
give  an  emulsion  only  after  vigorous  and  prolonged  shaking,  but  the 
emulsion  is  not  persistent.  The  jiresence  of  some  soap  causes  a  very  fine 
and  permanent  emulsion  to  form  easily.  Fat  produces  spots  on  paper 
which  do  not  disappear;  it  is  not  volatile;  it  boils  at  about  300°  C.  with 
partial  decomposition,  and  burns  with  a  luminous  and  smoky  flame.  The 
fatty  acids  have  most  of  the  above-mentioned  properties  in  common  with 
the  neutral  fats,  but  differ  from  them  in  being  soluble  in  alcohol-ether,  in 
having  an  acid  reaction,  and  by  not  giving  the  acrolein  test.  The  neutral 
fats  generate  a  strong  irritating  vapor  of  acrolein,  due  to  the  decomposition 
of  glycerine,  03X1,(011)3  —  271,0  =  CjIT^O,  when  heated  alone,  or  more 
easily  when  heated  with  potassium  bisnlphate  or  with  other  dehydrating 
substances. 

The  neutral  fats  may  be  split  by  the  addition  of  the  constituents 
of  water  according  to  the  following  equation:  0,IL(0R)3  +  311,0  = 
CjH^fOH),  +  3II0R.  This  splitting  may  be  produced  by  steapsin,  similar 
enzymes  occurring  in  the  plant  kingdom  or  by  superheated  steam.  We 
most  frequently  decompose  the  neutral  fats  by  boiling  them  with  caustic 
alkali  not  too  concentrated,  or,  still  better  (in  zoochemical  researches),  with 
an  alcoholic  potash  solution  or  sodium  alcoholate.  By  this  procedure, 
which  is  called  saponification,  the  alkali  salts  of  the  fatty  acids  (soaps)  are 
formed.     If  the  saponification  is  made  with  lead  oxide,  then  lead-plaster, 

'  See  KnOpfelmacher.  "  Untersuch.  tlber  das  Fett  Im  Saugllngsalter,"  etc.,  Jahrbuch 
f.  Kinderheilkundc  (N.  F. ).  Bd.  Ah,  which  also  contahis  the  older  literature. 


94  THE  ANIMAL  FATS. 

lead-salt  of  the  fatty  acids,  is  produced.  We  do  not  only  call  the  cleavage 
of  neutral  fats  by  alkalies  saponification,  but  also  the  splitting  of  neutral 
fats  into  fatty  acids  and  glycerin  in  general. 

On  keeping  fats  for  a  long  time  in  contact  with  air  they  undergo  a 
change,  becoming  yellow  in  color,  acid  in  reaction,  and  develop  an  unpleas- 
ant odor  and  taste.  It  becomes  rancid,  and  in  this  change  a  part  of  the 
fat  is  split  into  fatty  acids  and  glycerin,  and  then  an  oxidation  of  the  free 
fatty  acids  takes  place,  producing  volatile  bodies  of  an  unpleasant  odor. 
The  rancidity  is  not  due,  as  shown  by  Gaffky  and  Eitsert,^  to  the  pres- 
ence of  microbes.  According  to  these  investigators  the  change  is  due  to  the 
combined  action  of  air  and  light. 

The  three  most  important  fats  of  the  animal  kingdom  are  stearin^ 
palmitin,  and  olein. 

Stearin,  or  tristeakik,  C,H^(CjJIj,0j3,  occurs  especially  in  the  solid 
varieties  of  tallow,  but  also  in  the  vegetable  fats. 

Stearic  acid,  C^jH^gO,,  is  found  in  the  free  state  in  decomposed  pus,  in 
the  expectorations  in  gangrene  of  the  lungs,  and  in  cheesy  tuberculous 
masses.  It  occurs  as  lime-soap  in  excrements  and  adipocere,  and  in  this 
last  product  also  as  an  ammonia  soap.  It  perhaps  exists  as  sodium  soap  in 
the  blood,  transudations,  and  pus. 

Stearin  is  the  hardest  and  most  insoluble  of  the  three  ordinary  neutral 
fats.  It  is  nearly  insoluble  in  cold  alcohol  and  soluble  with  great  difficulty 
in  cold  ether  (225  parts).  It  separates  from  warm  alcohol  on  cooling  as 
rectangular,  less  frequently  as  rhombical  plates.  The  statements  in  regard 
to  the  melting-point  are  somewhat  varied.  Pure  stearin,  according  to 
IIeintz,^  melts  between  +  65°  and  71.5°.  The  stearin  from  the  fatty 
tissues  (not  pure)  melts  at  -|-  Go"  C. 

Stearic  acid  crystallizes  (on  cooling  from  boiling  alcohol)  in  large, 
shining,  long-rhombical  scales  or  plates.  It  is  less  soluble  than  the  other 
fatty  acids  and  melts  at  09.2°  C.     Its  barium  salt  contains  19.49^  barium. 

Palmitin,  tripalmitin,  0,11^(0,, IIg,0 J j.  Of  the  tvv-o  solid  varieties  of 
fats,  palmitin  is  the  one  which  occurs  in  predominant  quantities  in  human 
fat  (Laxgek).'  Palmitin  is  present  in  all  animal  fats  and  in  several  kinds 
of  vegetable  fats.     A  mixture  of  stearin  and  palmitin  was  formerly  called 

MARGARIN. 

Palmitic  acid,  C^Jl^^O^.  As  to  occurrence,  about  the  same  remarks 
apply  as  to  stearic  acid.  The  mixture  of  these  two  acids  has  been  called 
margaric  acid,  and  this  mixture  occurs — often  as  very  long,  thin,  crystalline 
plates — in  old  pus,  in  expectorations  from  gangrene  of  the  Inngs,  etc. 

'  Naturwissenscb.  Wocheuscbr.,  1890. 

«  Annal.  d.  Chem.  ti.  Phnrm.,  Bd.  92,  S.  300. 

«  Monalsbefle  f.  Cbem.,  Bd.  2. 


OLEIC  ACID  95 

Palmitiu  crystallizes,  on  cooling  from  a  Avarm  saturated  solution  in  ether 
or  alcohol,  in  starry  rosettes  of  fiue  needles.  The  mixture  of  palmitin  and 
etearin,  called  margarin,  crystallizes,  on  cooling  from  a  solution,  as  balls  or 
round  masses  whi^ch  consist  of  short  or  long,  thin  plates  or  needles  which 
often  appear  like  blades  of  grass.  Palmitin,  like  stearin,  has  a  variable 
melting  and  solidifying  point,  depending  upon  the  way  it  has  been  pre- 
vionsly  treated.  The  melting-point  is  often  given  as  +  G2°.  According 
to  other  statements'  it  melts  at  50.5°  C,  solidifies  on  further  heat  and 
melts  again  at  GG°.50  C. 

Palmitic  acid  crystallizes  from  an  alcoholic  solution  in  tufts  of  fine 
needles.  It  melts  at  +  G2°  C. ;  still  the  admixture  with  stearic  acid,  as 
IIeixtz  has  shown,  essentially  changes  the  melting  and  solidifying  points 
according  to  the  relative  amounts  of  the  two  acids.  Palmitic  is  somewhat 
more  soluble  in  cold  alcohol  than  stearic  acid ;  but  they  have  about  the  same 
solubility  in  boiling  alcohol,  ether,  chloroform,  and  benzol.  Its  barium  salt 
contains  21.17j^  barium. 

Olein,  TRiOLEix,  CJI,(C„n„OJ„  is  present  in  all  animal  fats  and  in 
greater  quantities  in  jilant  fats.  It  is  a  solvent  for  stearin  and  palmitin. 
Oleic  acid,  elaic  acid,  0,^11,^0,,  occurs  probably  as  soaps  in  the  intestinal 
canal  during  digestion  and  in  the  chyle. 

Olein  is,  at  ordinary  temperatures,  a  nearly  colorless  oil  of  a  specific 
gravity  of  0.01-4,  without  odor  or  marked  taste.  It  solidifies  in  crystalline 
needles  at  —  5°  C.  It  becomes  rancid  quickly  if  exposed  to  the  air.  It 
dissolves  with  difficulty  in  cold  alcohol,  but  more  easily  in  warm  alcohol  or 
in  ether.     It  is  converted  into  its  isomer,  elaidin,  by  nitrons  acid. 

Oleic  acid  forms  on  heating,  besides  volatile  acids,  sebacic  acid^ 
C,„II,gO^,  crystallizing  in  shining  leaves  and  melting  at  127°  C.  "With 
nitrous  acid  oleic  acid  is  transformed  into  the  isomeric,  solid,  elaiclic  acid, 
which  melts  at  45°  C.  Oleic  acid  forms  at  ordinary  temperature  a  colorless, 
tasteless,  and  odorless  oily  liquid  which  solidifies  in  crystals  at  about 
+  4°  C,  which  then  melt  again  at  +  14°  C.  Oleic  acid  is  insoluble  in 
water,  but  dissolves  in  alcohol,  ether,  and  chloroform.  With  concentrated 
sulphuric  acid  and  some  cane-sugar  it  gives  a  beautiful  red  or  reddish- violet 
liquid  whose  color  is  similar  to  that  produced  in  Pettenkoffer's  test  for 
bile-acids.  Oleic  acid  is  an  unsaturated  fatty  acid,  which  can  take  up 
halogens.  On  heating  with  hydroiodic  acid  and  amorphous  i)hosi)horus  it 
takes  up  hydrogen  and  is  converted  into  stearic  acid. 

If  the  watery  solution  of  the  alkali  combinations  of  oleic  acid  is  preci|)i- 
tated  with  lead  acetate,  a  white,  tough,  sticky  mass  of  lead  oleate  is 
obtained  which  is  not  soluble  in  water  and  only  slightly  in  alcohol,  but  is 
soluble  in  ether.  This  is  made  use  of  in  separating  oleic  acid  from  the 
other  two  fatty  acids,  whose  lead  salts  are  not  quite  insoluble  in  ether, 
'  R.  Benedikt,  Analyse  der  Fetle.     3  Aufl.,  1897.     S.  44. 


96  THE  ANIMAL  FATS. 

An  acid  related  to  oleiq  acid,  doeglic  acid,  vrhicli  is  solid  at  0°  C,  liquid  at  +  1^°. 
and  soluble  in  nlcoliol,  is  found  in  the  blubber  of  \he  Balcsna  rostrata.  Kurbatoff  ' 
has  demonstrated  tlie  presence  of  linoleic  acid  in  the  fat  of  the  silurus,  sturgeon,  seal, 
and  certain  oiher  animals.  Drying  fats  have  also  been  found  by  Amthok  and  Zink-  in 
hares,  wild  rabbits,  wild  boar,  and  mountain-cock. 

To  detect  the  presence  of  fat  in  an  animal  fluid  or  tissue  the  fat  must 
first  be  extracted  with  ether.  After  the  evaporation  of  the  ether  the 
residue  is  tested  for  fat  and  the  acrolein  test  must  not  be  neglected.  IE  this 
test  gives  positive  results,  then  neutral  fats  are  present;  if  the  results  are 
negative,  then  only  fatty  acids  are  present.  If  the  above  residue  after 
evaporation  gives  the  acrolein  test,  then  a  small  portion  is  dissolved  in 
alcohol-ether  free  from  acid  and  which  has  been  colored  bluish  violet  by 
tincture  of  alkanet.  If  the  color  becomes  red,  a  mixture  of  neutral  fat  and 
fatty  acids  is  present.  In  this  case  the  fat  is  treated  in  the  warmth  with  a 
soda  solution  and  evaporated  on  the  water-bath,  constantly  stirring  until 
all  the  water  is  removed.  The  fatty  acids  hereby  combine  with  the  alkali, 
forming  soaps,  while  the  neutral  fats  are  not  saponified  under  these  condi- 
tions. If  this  mixture  of  soaps  and  neutral  fats  is  treated  with  water  and 
then  shaken  with  pure  ether,  the  neutral  fats  are  dissolved,  while  the  soaps 
remain  in  the  watery  solution.  The  fatty  acids  may  be  separated  from  this 
solution  by  the  addition  of  a  mineral  acid  which  sets  the  acid  free. 

The  neutral  fats  separated  from  the  soaps  by  means  of  ether  are  often 
contaminated  with  cholesterin,  which  must  be  separated  in  quantitative 
determinations  by  saponification  with  alcoholic  caustic  potash.  The 
cholesterin  is  not  attacked  by  the  caustic  alkali,  while  the  neutral  fats  are 
saponified.  After  the  evaporation  of  the  alcohol  the  residue  is  dissolved  in 
water  and  shaken  with  ether,  which  dissolves  the  cholesterin.  The  fatty 
acids  are  separated  from  the  watery  solution  of  the  soaps  by  the  addition  of 
a  mineral  acid.  If  a  mixture  of  soaps,  neutral  fats,  and  fatty  acids  is 
originally  present,  it  is  treated  first  with  water,  then  agitated  with  ether 
free  from  alcohol,  which  dissolves  the  fat  and  fatty  acids,  while  the  soaps 
remain  in  the  solution,  with  the  exception  of  a  very  small  amount  which  is 
dissolved  by  the  ether. 

To  detect  and  to  separate  the  different  varieties  of  neutral  fats  from 
each  other  it  is  best  first  to  saponify  them  with  alcoholic  potash,  or  still 
better  with  sodium  alcoholate,  according  to  Kossel,  Obeemuller,  and 
Kruger.'  After  the  evaporation  of  the  alcohol  they  are  dissolved  in  water 
and  precipitated  with' sugar  of  lead.  The  lead  oleate  is  then  separated  from 
the  other  two  lead-salts  by  repeated  extraction  with  ether,  but  it  mast  be 
remarked  that  the  lead-salts  of  the  other  fatty  acids  are  not  quite  insoluble 
in  ether.  The  residue  insoluble  in  ether  is  decomposed  on  the  water-bath 
with  an  excess  of  soda  solution,  evaporated  to  dryness,  finely  pulverized, 
and  extracted  with  boiling  alcohol.  Tiie  alcoholic  solution  is  then  frac- 
tionally precipitated  by  barium  acetate  or  barium  chloride.  In  one  fraction 
the  amount  of  barium  is  determined,  and  in  the  other  the  melting-point  of 
the  fatty  acid  set  free  by  a  mineral  acid.  The  fatty  acids  occurring 
originally  in  the  animal  tissues  or  fluids  as  free  acids  or  as  soaps  are  con- 
verted into  barium  salts  and  investigated  as  above. 

>  Maly's  Jahresber.,  Bd.  22. 

'  Zeitschr.  f.  analyt.  Chem.,  Bd.  36. 

"  Zeitschr.  f.  physiol.  Chora.,  Bdd.  14,  15,  and  16. 


ESTIMATION  OF  FATS.  97 

Besides  the  methods  already  suggested  there  are  other  chemical  methods 
which  are  important  in  investigating  fats.  liesides  determining  the  melt- 
ing and  solidification  ]ioint  we  also  determine  tiie  following:  1,  The  acid 
equivalent^  which  is  a  measure  of  the  amount  of  fatty  acids  in  a  fat  and  is 

determined  by  titrating  the  fat  dissolved  in  alcohol-ether  with  — •  alcoholic 

JO  20 

caustic  potash,  using  phenolphtalein  as  indicator.  3.  The  saponification 
equivalent.,  whicli  gives  the  milligrams  of  caustic  potash  united  with  the 

fatty  acids  in  the  saponification  of    1  gm.  fat  with   (-1  alcoholic  caustic 

potash.  3.  Keiciiert-]\Ieissl's  equivalent.,  which  gives  the  quantity  of 
volatile  fatty  acids  contained  in  a  given  amount  of  neutral  fat  (5  gms.). 
The  fat  is  saponified,  then  acidified  with  mineral  acid  and  distilled,  whereby 
the  volatile  fatty  acids  pass  over  and  the  distillate  is  titrated  with  alkali. 
4.  Iodine  equivalent  is  the  quantity  of  iodine  absorbed  by  a  certain  amount 
of  the  fat  by  addition.  It  is  chielly  a  measure  of  the  quantity  of  unsatu- 
rated fatty  acids,  in  the  first  place  oleic  acid  or  olein  in  the  fat.  Other 
bodies  such  as  cholesterin  may  also  absorb  iodine  or  halogens.  The  iodine 
equivalent  is  generally  determined  according  to  the  method  suggested  by 
V.  HtJBL.  5.  The  acetyl  equivalent.  Oxyacids,  alcohols  such  as  cetyl 
alcohol  or  cholesterin  and  such  constituents  of  fats  containing  the  OH 
group,  are  transformed  into  the  corresponding  acetyl  ester  on  boiling  with 
acetic  acid  anhydride  while  the  fatty  acids  remain  unchanged,  and  in  this 
way  the  estimation  of  these  bodies  is  possible.  The  fat  is  saponified,  the 
soaps  decomposed  by  an  excess  of  acid  and  the  mixture  of  fatty  acids, 
oxyfatty  acids,  cholesterin,  etc.,  boiled  witli  acetic  acid  anhydride.  The 
acid  equivalent  is  determined  in  a  weighed  part  of  the  carefully  washed 
acetic  acid  free  mixture  by  titration  with  an  alcoholic  caustic  potash.  This 
acid  equivalent  represents  all  the  acids  (fatty  acids  as  well  as  the  acetylated 
oxyacids)  and  it  is  designated  the  acetyl  acid  equivalent.  The  neutral  fiuid 
is  now  titrated  with  an  exactly  measured,  sufficient,  quantity  of  the  same 
alkali  and  the  acetyl  compounds  saponified  by  boiling.  On  retitrating  we 
find  the  quantity  of  alkali  used  in  saponification  and  this  number,  calculated 
to  100  parts  of  the  fat  represents  the  acetyl  equivalent.  In  regard  to  the 
performance  of  the  above-mentioned  different  estimations  we  must  refer  the 
reader  to  more  complete  works  such  as  "  Analysis  of  Fats  and  AVaxes," 
It.  Benedikt. 

In  the  ([uantitative  estimation  of  fats  the  finely  divided  dried  tissues  or 
the  finely  divided  residue  from  an  evaporated  fluid  is  extracted  with  ether, 
alcohol-ether,  benzol,  or  any  other  i)roper  extraction  medium.  The  investi- 
gations of  DoKMEYKK'  and  others,  carried  on  in  Pi-luger's  laboratory,  have 
shown  that  even  with  very  prolonged  extraction  with  ether  all  the  fat  is  not 
extracted.  First  extract  the  greater  part  of  the  fat  by  ether.  Then  digest 
with  pepsin  hydrochloric  acid,  collect  the  insoluble  residue  on  a  filter,  dry 
and  extract  with  ether.  The  fat  is  extracted  from  the  filtrate  by  shaking 
with  ether,  evaporating  the  extract  and  the  fat  separated  from  other  bodies 

'  On  fat  extraction  for  quantitative  estimation  see  :  Dormeyer,  Pfliiger's  Arch.,  Bdd. 
61  and  65  ;  Bogdauow,  ibid.,  Bdd.  65,  68,  and  Du  Bois-Ileymond's  Arch.,  1897,  S.  149  ; 
N.  Scbulz,  Pfliiger's  Arch.,  Bd.  66;  Voit  and  Knimmacher,  Zeitschr.  f.  Biologie,  Bd.  35; 
O.  Frank,  ibid.,  Bd.  35  ;  Polinianti,  Pfluger's  Arch.,  Bd.  70  ;  J.  Nerking,  i^id.,  Bd.  71. 


98  THE  ANIMAL  FATS. 

by  extracting  the  residue  with  petroleum  ether.  J.  Nerking  '  has  simpli- 
fied the  fat  estimation  by  the  digestion  method  by  constructing  a  special 
apparatus.  L.  Liebermann  and  Szekely  '  have  suggested  a  new  method 
of  fat  estimation,  which  according  to  Tangl  and  Weiser'  is  as  good  as 
Dormeter's  method  and  can  be  performed  much  quicker. 

The  fats  are  poor  in  oxygen  but  rich  in  carbon  and  hydrogen.  They 
therefore  represent  a  large  amount  of  chemical  potential  energy,  and  yield 
correspondingly  large  quantities  of  heat  on  combustion.  They  take  firsts 
rank  amongst  the  foods  in  this  regard,  and  are  therefore  of  very  great 
importance  in  animal  life.  We  will  speak  more  in  detail  of  this  signifi- 
cance, also  of  fat  formation  and  the  behavior  of  the  fats  in  the  body,  in  the 
following  chapters. 

The  LECITHINS,  which  stand  in  close  relationship  to  the  fats,  will  be 
treated  of  in  a  subsequent  chapter.  The  following  bodies  append  them- 
selves to  the  ordinary  animal  fats. 

Spermaceti.  lu  the  living  spermaceti  or  white  whale  there  is  found  in  a  large  cavity 
fn  the  skull  an  oily  liquid  called  spermaceti,  which  on  cooling  after  death  separates  into 
a  solid  crystalline  part,  ordinarily  called  spermaceti,  and  into  a  liquid,  spermaceti-oil. 
This  last/ is  separated  by  pressure.  Spermaceti  is  also  found  in  other  -whales  and  in  cer- 
tain species  of  dolphin. 

The  purified,  solid  spermaceti,  which  is  called  cetin,  is  a  mixture  of  esters  of  fatty 
acids.  The  chief  constituent  is  the  cetyl-palmitic  esler  mixed  with  small  quantities  of 
compound  ethers  of  lauric,  myrisitic,  and  stearic  acids  with  radicals  of  the  alcohols, 
lethal,  CiaHjs.OH,  methal,  C14H29.OH,  and  stethal,  C18H37.OH. 

Cetin  is  a  snow-white  mass  shining  like  mother-of-pearl,  crystallizing  in  plates,  brittle, 
fatty  to  the  touch,  and  which  has  a  varying  melting-point  of  -|-  30°  to  50°  C.,  depending 
upon  its  purity.  Cetin  is  insoluble  in  water,  but  dissolves  easily  in  cold  ether  or  volatile 
and  tatty  oils.  It  dissolves  in  boiling  alcohol,  but  crystallizes  on  cooling.  It  is  saponi- 
fied with  difficulty  by  a  solution  of  caustic  potash  in  Avater,  but  with  an  alcoholic  solu- 
tion it  saponifies  readily  and  the  above-mentioned  alcohols  are  set  free. 

Ethal,  or  cetyl  alcohol,  CfiHss.OH,  which  also  occurs  in  the  coccygeal  gland  of 
ducks  and  geese  (De  Jonge  ■•)  and  in  smaller  quantities  in  beeswax,  and  found  by  LuD- 
wiG  and  V.  Zeynek^  in  the  fat  from  dermoid  cysts,  forms  white,  transparent,  odorless, 
and  tasteless  crystals  which  are  insoluble  in  water  but  dissolve  easily  in  alcohol  and 
ether.     Etlial  melts  at  49.5°  C. 

Spermaceti-oil  yields  on  saponification  valerianic  acid,  small  amounts  of  solid  fatty 
acids,  and  puysetoleic  acid.  This  acid,  which  has,  like  hypogasic  acid,  the  composi- 
tion C.bHsoOj,  occurs  also,  as  found  by  Ljubarsky,^  in  considerable  amounts  in  the  fat 
of  the  seal.  It  forms  colorless  and  odorless,  needle-shaped  crystals  which  easily  dissolve 
Id  alcohol  and  ether  and  melt  at  -|-  34°  C. 

Beeswax  may  be  treated  here  as  concluding  the  subject  of  fats.  It  contains  three 
chief  constituents  :  1  Cerotic  acid,  CitHmOj  .'which  occurs  as  cetyl  ether  in  Chinese 
wax  and  as  free  acid  in  ordinary  wax.  It  dissolves  in  boiling  alcoliol  and  separates  as 
crystals  on  cooling.  Tlie  cooled  alcoholic  extract  of  wax  contains  (2)  cerolein,  which 
is  probably  a  mixture  of  several  bodies,  and  (3)  myrisin,  which  forms  the  chief  con- 
stituent of  tliat  part  of  wax  which  is  insoluble  in  warm  or  cold  alcoliol.  Myrisin  consists 
cliiedy  of  palmitic-acid  ether  of  melissyl  (myricyl)  alcohol,  CsoHoi  .011.  This  alcohol  is 
a  silky,  shining,  crystalline  body  melting  at  -f-  85°  C. 

'  Pfl tiger's  Arch.,  Bd.  73. 

»  Ibid.,  Bd.  72. 

*  Ibid.,  Bd.  72,  S.  367. 

♦  Zeitschr.  f.  physiol.  Chem.,  Bd.  3. 
»  Ibid.,  Bd.  23. 

« Journ.  f.  prakt.  Chem.  (N.  F.),  Bd.  57. 

''  See  Ileuriques,  Ber.  d.  deutsch.  chem.  Gescllsch.,  Bd.  30,  S.  1415. 


CHAPTER  V. 

THE   ANIMAL   CELL. 

The  cell  is  the  nnit  of  tlie  manifold,  variable  forms  of  the  organism;  it 
forms  the  simplest  physiological  apparatus,  and  as  such  is  the  seat  of  chem- 
ical processes.  It  is  generally  admitted  that  all  chemical  processes  of 
importance  do  not  take  jilace  in  the  animal  fluids,  but  transpire  in  the 
cells,  which  may  be  considered  as  the  chemical  laboratory  of  the  organism. 
It  is  also  principally  the  cells  which,  through  their  greater  or  less  activity, 
regnlate  or  govern  the  range  of  the  chemical  processes  and  also  the  intensity 
of  the  total  exchange  of  material. 

It  is  natural  that  the  chemical  investigation  of  the  animal  cell  should  in 
most  cases  coincide  with  the  study  of  those  tissues  of  which  it  forms  the 
chief  constituent.  Only  in  a  few  cases  can  the  cells  be  directly,  by  rela- 
tively simple  manipulations,  isolated  in  a  rather  pure  state  from  the  tissues, 
as,  for  example,  in  the  investigation  of  pus  or  of  tissue  very  rich  in  cells. 
But  even  in  these  cases  the  chemical  investigation  may  not  lead  to  any  posi- 
tive results  in  regard  to  the  constituents  of  the  uninjured  living  cells.  By 
the  process  of  chemical  transformation  new  substances  may  be  formed  on 
the  death  of  the  cell,  and  at  the  same  time  j^hysiological  constituents  of  the 
cell  may  be  destroyed  or  transported  into  the  surrounding  medium  and 
therefore  escape  investigation.  For  this  and  other  reasons  we  possess  only 
a  very  limited  knowledge  of  the  constituents  and  the  composition  of  the 
cell,  especially  of  the  living  one. 

While  young  cells  of  different  origin  in  the  early  period  of  their  exist- 
ence may  show  a  certain  similarity  in  regard  to  form  and  chemical  composi- 
tion, they  may,  on  further  development,  not  only  take  the  most  varied 
forms,  but  may  also  offer  from  a  chemical  standpoint  the  greatest  diversity. 
As  a  description  of  the  constituents  and  composition  of  the  different  cells 
occurring  in  tlie  animal  organism  is  nearly  equivalent  to  a  demonstration  of 
the  chemical  properties  of  most  animal  tissues,  and  as  this  exposition  will  be 
found  in  their  respective  chapters,  we  will  here  only  discuss  the  chemical 
constituents  of  the  young  cells  or  the  cells  in  general. 

In  the  study  of  these  constituents  we  are  confronted  with  another 
difficulty,  namely,  we  must  differentiate  by  chemical  research  between  those 

99 


100  THE  ANIMAL   CELL. 

constitnents  -wliicli  are  essentially  necessary  for  the  life  of  the  cells  and 
those  which  are  casual,  i.e.,  stored  up  as  reserve  material  or  as  metabolic 
products.  In  this  connection  we  have  only  been  able,  thus  far,  to  learn  of 
certain  substances  which  seem  to  occur  in  every  developing  cell.  Such 
bodies,  called  primary  by  Kossel,'  are,  besides  water  and  certain  mineral 
coustitnents,  proteids,  nucleoproteids  or  necleins,  lecithins,  glycogen  (?), 
and  cholesterin.  Those  bodies  which  do  not  occur  in  every  developing  cell 
are  called  secoxdary.  Amongst  these  we  have  fat,  glycogen  (?),  pigments, 
etc.  It  must  not  be  forgotten  that  it  is  still  possible  that  other  primary 
cell  constituents  may  exist,  but  unknown  to  us,  and  we  also  do  not  know 
whether  all  the  primary  constituents  of  the  cell  are  necessary  or  essential 
for  the  life  and  functions  of  the  same.  We  do  not  know,  for  example, 
whether  the  ever-present  cholesterin  is  an  excretory  product  of  the  meta- 
bolism within  tlie  cell  or  whether  it  is  necessary  for  the  life  and  development 
of  the  same. 

Another  important  question  is  the  division  of  the  various  cell  constit- 
nents between  the  two  morphological  components  of  the  cell,  namely,  the 
protoplasm  and  the  nucleus.  This  is  very  difficult  to  decide  for  many  of 
the  constituents,  nevertheless  it  is  appropriate  to  differentiate  between  the 
protoplasm  and  the  nucleus. 

The  Protoplasm  of  the  developing  cell  consists  during  life  of  a  semi-solid 
mass,  contractile  under  certain  conditions  and  readily  changeable,  which  is 
rich  in  water  and  whose  chief  portion  consists  of  protein  substances.  If 
the  cell  be  deprived  of  the  physiological  conditions  of  life,  or  if  exposed  to 
destructive  exterior  influences,  such  as  the  action  of  high  temperatures,  of 
chemical  agents,  or  indeed  of  distilled  water,  the  protoplasm  dies.  The 
albuminous  bodies  which  it  contains  coagulate  at  least  partiall}',  and  other 
chemical  changes  are  found  to  take  place.  The  alkaline  reaction  of  the 
living  cell  may  be  converted  into  an  acid  by  the  appearance  of  paralactic 
acid,  and  the  carbohydrate,  glycogen,  Avhich  habitually  occurs  in  the  young 
generative  cell  may  after  its  death  be  quickly  changed  and  consumed. 

The  question  as  to  the  internal  structure  of  the  protoplasm  is  still  in 
controversy.  It  is  of  little  importance  in  the  study  of  the  chemical  composi- 
tion of  the  cells,  as  it  is  impossible  to  chemically  study  the  morphologically 
different  constituents  of  the  protoplasm.  With  the  exception  of  a  few 
micro-chemical  reactions  the  chemical  analysis  has  been  restricted  to  the 
protoplasm  as  snch,  and  the  investigations  have  been  directed  in  the  first 
place  to  the  protein  substances  which  form  the  chief  mass  of  the  protoplasm. 

Tlie  proteids  of  the  j^Totoplasm  consist,  according  to  the  general  view, 
chiefly  of  globulins.  Albnmins  have  also  been  found  besides  the  globulins. 
There  is  no  doubt  at  present  that  the  albumins  occur  in  the  cells  only  as 


•  Verhandl.  d.  physiol.  Gesellsch.  zu  Berlin,  1890-91,  Nos.  5  and  6. 


PROTEIDS  OF  THE  PROTOPLASM.  101 

traces,  or  at  least  only  in  trifling  quantities.  The  presence  of  globulins  can 
liardly  be  disputed,  although  certain  cell  constituents  described  as  glolnilins 
have  been  shown  on  closer  investigation  to  be  nucleoalbnniins  or  nucleo- 
proteids.  According  to  Halliburton  '  the  proteid  occurring  in  all  cells 
and  coagulating  at  47°-50°  C.  is  a  true  globulin. 

In  opposition  to  the  view  that  the  chief  mass  of  the  animal  cell  consists 
of  true  proteids,  the  author'  expressed  the  opinion  several  years  ago  that 
tiie  chief  mass  of  the  protein  substances  of  the  cells  does  not  consist  of 
proteids  in  the  ordinary  sense,  but  consists  of  more  complex  phosphorized 
bodies,  and  that  the  globulins  and  albumins  are  to  be  considered  as  nutritive 
material  for  the  cells  or  as  destructive  products  in  the  chemical  transforma- 
tion of  the  protoplasm.  This  view  has  received  substantial  support  by 
investigations  within  the  last  few  years.  Alex.  Schmidt'  has  come  to  the 
view,  by  investigations  on  various  kinds  of  cells,  that  they  contain  only  very 
little  proteid,  and  that  the  chief  mass  consists  of  very  complex  protein 
substances.  Liliexfeld^  has  also  found  on  a  quantitative  analysis  of 
leucocytes  from  the  thymus  gland  only  1.70,'^  proteid  (in  the  dried  sub- 
stance), in  the  ordinary  sense. 

The  protein  substances  of  the  cells  consist  chiefly  of  compound  proteids, 
and  these  are  divided  between  the  glycoproteid  and  the  nucleoproteid 
groups.  It  is  impossible  at  present  to  state  the  extent  of  nncleoalbumins  in 
the  cells  because  thus  far  in  most  cases  no  exact  difference  has  been  made 
between  them  and  the  nucleoproteids.  Hoppe-Seyler  '  calls  viteUin  a 
regular  constituent  of  all  protoplasm.  This  body  used  to  be  considered  as 
a  globulin,  but  later  researches  have  shown  that  the  so-called  vitelline  bodies 
may  be  of  various  kinds.  Certain  vitellins  seem  to  be  nncleoalbumins,  and 
it  is  therefore  very  probable  that  cells  habitually  contain  nucleoalbumins. 

The  7in('Ieoj)7'ofeids  take  a  very  prominent  place  among  the  compound 
proteids  of  the  cell.  The  various  substances  isolated  by  different  investiga- 
tors from  animal  cells,  such  as  tissiie-Jibrinoge:i  (Wooldridge),  cytoglohin 
and  prefflobului  (Alex.  Schmidt),  or  nuchohision  (Kossel  and  Lilien- 
I'ELd"),  belong  to  this  group.  The  cell  constituent  which  swells  up  to  a, 
sticky  mass  with  common  salt  solution  and  is  called  Rovida's  hyaline  sub' 
stance  also  belongs  to  this  group. 

The  above-mentioned  different  protein  substances  have  only  been  simply 


'  See  Iltillibiirlon,   On  the  Cliemical  Physiology  of  the  Animal  Cell,  1898,  No.  1, 
King's  College  Physiol.  Laboratory. 
«  Pflliger's  Arch.,  Bd.  36,  S.  449. 
3  Alex.  Schmidt,  Zur  Blutlehre.     Leipzig,  1893. 

*  Zeilschr.  f.  physiol   Chem.,  Bd.  18,  S.  485. 

*  Physiol.  Chem".,  1877-1881.  S.  76. 

'  See  L.  C.  Wooldridge,  Die  Gerinnung  des  Blutes.     Leipzig.  1891 ;— A.  Schmidt, 
Zur  Blutlehre  ;  Lilienfeld,  1.  c. 


102  THE  ANIMAL   CELL. 

designated  as  constituents  of  the  cells.  The  next  question  is  which  of  these 
belong  to  the  protoplasm  and  which  to  the  nucleus.  At  present  we  can 
give  no  positive  ans^^*e^  to  this  question.  According  to  Kossel  and  Lilieist- 
feld/  the  cell-nucleus  of  the  leucocytes  contains  a  nucleoproteid,  besides 
nucleins,  as  chief  constituent,  and  sometimes  perhaps  also  nucleic  acid  (see 
below),  while  the  body  of  the  cells  contains  chiefly  pure  proteins  besides 
-other  substances,  and  only  a  little  nucleoalbumin,  containing  a  very  small 
quantity  of  phosphorus.  This  view  coincides  well  with  the  obseiwations  of 
Liliexfeld  on  the  behavior  of  the  protoplasm  and  cell-nucleus  on  one  side, 
as  compared  with  the  proteids  and  nuclein  substances  with  certain  coloring 
matters;  but  it  seems  to  be  inconsistent  with  the  quantitative  composition 
of  the  leucocytes  as  found  by  Lilienfeld.  If  we  admit,  according  to 
Kossel  and  Lilienfeld,  that  the  nucleoproteid,  called  by  them  nucleo- 
histon,  belongs  only  to  the  nucleus  of  the  leucocytes  of  the  thymus  gland, 
then  77.45  parts  of  the  79.21  parts  of  proteins  in  100  parts  of  the  dried 
substance  belongs  to  the  nucleus  and  only  1.76  parts  to  the  protoplasm. 
As  the  lymphocytes  of  the  thymus  gland  of  the  calf  contain  only  one 
nucleu^,  in  which  the  mass  of  the  nucleus  surpasses  that  of  the  cytoplasm, 
jt  is  natural  that  the  relative  proportion  of  the  various  .protein  substances  in 
these  cells  cannot  be  taken  as  a  standard  for  the  composition  of  other  cells 
richer  in  cytoplasm. 

Complete  investigations  in  regard  to  the  distribution  of  protein  sub- 
stances in  the  protoplasm  and  nucleus  of  other  cells  have  not  been  made. 
If  we  consider  for  the  present  that  the  cells  rich  in  protoplasm  contain,  as 
a  rule,  only  very  little  trne  proteid,  we  are  hardly  wrong  in  considering  it 
probable  that  the  protoplasm  contains  chiefly  nncleoalbumins  and  compound 
proteids  besides  traces  of  albumin  and  a  little  globulin.  These  compound 
proteids  are  in  certain  cases  glycoproteids,  but  otherwise  nucleoproteids, 
which  difl'er  from  the  nucleoproteids  of  the  nucleus  in  being  poorer  in 
phosphorus,  besides  containing  a  great  deal  of  proteid  and  only  less  of  the 
prostetic  group,  and  hence  have  no  specially  pronounced  acid  character. 

The  nucleoproteids  of  the  nucleus  are  on  the  contrary,  as  shown  by 
LiLiEKFELD  and  Kossel,  rich  in  phosphorus  and  of  a  strongly  acid  charac- 
ter. These  nucleoproteids  will  be  treated  of  in  speaking  of  the  nucleins  of 
the  nucleus. 

In  cases  in  which  the  protoplasm  is  surrounded  by  an  outer,  condensed 
layer  or  a  cell  membrane,  this  envelope  seems  to  consist  of  albumoid  sub- 
stances. In  a  few  cases  these  substances  seem  to  be  closely  related  to 
elastin;  in  other  cases,  on  the  contrary,  they  seem  rather  to  belong  to  the 
keratin  group.     The  chemical  processes  by  which  these  albumoid  substances 


'  Ueber  die  "Wahlverwnndtschaft  der  Zellelemente  zu  gewissen  Parbstoffen.     Ver- 
handl.  d.  physiol.  Gesellsch.  zu  Eerliii,  No.  11,  1893. 


LECirUIN.  103 

are  formed  from  the  albuminous  bodies  or  compound  proteids  of  the  proto- 
plasm are  unknown. 

Among  the  non-proteid  substances  of  the  cell  we  must  first  mention 
lecithin,  which  exists  as  a  positive  constituent  of  the  protoplasm.  It  is 
difficult  to  say  whether  it  also  exists  in  the  nucleus. 

Lecithin.  This  body  is,  according  to  the  investigations  of  Strecker, 
Huxi)i:sha(;en',  and  Gilsox,'  an  ether-like  combination  of  glycerojjhos- 
phoric  acid  substituted  by  two  fatty  acid  radicals,  with  a  base,  cholin. 
Therefore  there  may  be  different  lecithins  according  to  the  fatty  acid  con- 
tained in  the  lecithin  molecule.  One  of  these — distearyllecithin — has  been 
closely  studied  by  IIoppk-Seyleu  and  Diacoxow:' 

CJI.„NPO,  =  II0.(CH,)3N.C.H,.0(0H)P0.0.C,H,  :  (C„H„0,),. 

In  agreement  with  this,  if  lecithin  be  boiled  with  baryta-water  it  yields 
fatty  acids,  glycerophosphoric  acid,  and  cholin.  It  is  only  slowly  decom- 
posed by  dilute  acids.  Besides  small  quantities  of  glycerophosphoric  acid 
(perhaps  also  distearylglycerophosphoric  acid)  we  have  large  quantities  of 
free  phosphoric  acid  split  off. 

CrLYCEROPnosPHORic  ACID  (H0)3P0.0.C,H,(0II),  is  a  bibasic  acid, 
which  probably  only  occurs  in  the  animal  lluids  and  tissues  as  cleavage 
product  of  lecthins.  The  cholix,  which  occurs  extensively  in  the  plant 
kingdom,  seems  to  be  identical  with  the  bases  sixcalix  (in  mnstard-sped) 
and  amaxitix  (in  agaricus  muscarius),  has  the  formula  nO.X(CII,),. 
C,H^.OII,  and  is  therefore  considered  as  trimethylethoxylium  hydrate. 
Cholin,  on  the  contrary,  is  not  identical  with  the  base,  x'eurix",  prepared 
by  Liebrp:ich  as  a  decomposition  product  from  the  brain,  which  is  consid- 
ered as  trimethylvinylium  hydrate,  1I0.N(CII,)3.C,H3.  Cholin  is  a  sirupy 
fluid  readily  miscible  with  absolute  alcohol.  Hydrochloric  acid  gives  a 
combination  which  is  very  soluble  in  water  and  alcohol,  but  insoluble  in 
ether,  chloroform,  and  benzol.  This  compound  forms  a  double  combination 
with  platinum  chloride  which  is  soluble  in  water,  insoluble  in  absolute 
alcohol  and  ether,  crystallizing  ordinarily  in  six-sided  orange-colored  plates. 
This  combination  is  used  in  the  detection  and  identification  of  this  base. 
Cholin  also  forms  a  crystalline  double  combination  with  mercuric  chloride 
and  gold  chloride.  In  watery  solution,  cholin,  on  prolonged  standing,  is 
converted  into  neurin,  which  process  may  be  hastened  by  micro-organisms.* 

Lecithin  occurs,  as  Hoppe-Seyler  *  has  especially  shown,  widely  diffused 

'  Strecker,  Anual.  d.  Chem.  u.  Pharm.,  Bd.  148  ;  Hundesbageu,  Journ.  f.  prakt. 
Chem.  (N.  F.).  Bd.  28  ;  Gilson,  Zeitschr.  f.  physiol.  Chem.,  Bd.  12. 

'  Hoppe-Seyler,  Med. -chem.  Uuteisuoli.,  S.  221  aud  405. 

^  Ueber  das  Choliu  und  seine  Verbiiidnugen,  see  Giilewitscb,  Zeitschr.  f.  physiol. 
Chem.,  Bdd.  24and26. 

*  Physiol.  Chem.     Berlin,  1877-81.     S.  57. 


104  THE  ANIMAL    CELL. 

ia  the  vegetable  and  animal  kingdoms.  According  to  this  investigator,  it 
occurs  also  in  many  cases  in  loose  combination  with  other  bodies,  such  as 
albuminous  bodies,  haemoglobin,  and  others.  Lecithin,  according  to 
Hoppe-Seyler,  is  found  in  nearly  all  animal  and  vegetable  cells  thus  far 
studied,  and  also  in  nearly  all  animal  fluids.  It  is  specially  abundant  in 
the  brain,  nerves,  fish-eggs,  yolk  of  the  egg,  electrical  organs  of  the  Torpedo 
electricus,  semen  and  pus,  and  also  in  the  muscles  and  blood-corpuscles, 
blood-plasma,  lymph,  milk,  especially  woman's  milk,  and  bile,  as  well  as  in 
other  animal  juices  and  liquids.  Lecithin  is  also  found  in  pathological 
tissues  or  liquids. 

This  wide  distribution  of  the  lecithins,  as  also  the  fact  that  it  is  a 
primary  constituent,  gives  great  physiological  importance  to  the  lecithins. 
We  have  in  lecithin,  no  doubt,  a  very  important  material  for  the  building 
up  of  the  complicated  phosphorized  nuclein  substances  of  the  cell  and  cell 
nacleus.  That  the  lecithins  are  of  great  importance  in  the  development 
and  growth  of  living  organisms,  in  fact  for  the  bioplastic  processes  in 
general,  follows  also  from  several  investigations.' 

Lecithin  may  be  obtained  in  grains  or  warty  masses  composed  of  small 
crystalline  plates  by  strongly  cooling  its  solution  in  strong  alcohol.  In  the 
dry  state  it  has  a  waxy  appearance,  is  plastic  and  soluble  in  alcohol,  espe- 
cially on  heating  (to  40-50"  C);  it  is  less  soluble  in  ether.  It  is  dissolved 
also  by  chloroform,  carbon  disalphide,  benzol,  and  fatty  oils.  It  swells  in 
water  to  a  pasty  mass  which  shows  under  the  microscope  slimy,  oily  drops 
and  threads,  so-called  myelin  forms  (see  Chapter  XII).  On  warming  this 
swollen  mass  or  the  concentrated  alcoholic  solation,  decomposition  takes 
place  with  the  production  of  a  brown  color.  On  allowing  the  solution  or 
the  swollen  mass  to  stand,  decomposition  takes  place  and  the  reaction 
becomes  acid.  In  putrefaction  lecithin  yields  glycerophosphoric  acid  and 
cholin;  the  latter  further  decomposes  with  the  formation  of  methylamin, 
ammonia,  carbon  dioxide,  and  marsh-gas  (Hasebroek^).  If  dry  lecithin 
be  heated  it  decomposes,  takes  fire  and  burns,  leaving  a  phosphorized  coke. 
On  fusing  with  caustic  alkali  and  saltpetre  it  yields  alkali  phosphates. 
Lecithin  is  easily  carried  down  during  the  precipitation  of  other  compounds 
such  as  the  proteid  bodies,  and  may  therefore  very  greatly  change  the  solu- 
bilities of  the  latter. 

Lecithin  combines  with  acids  and  bases.  The  combination  with  hydro- 
chloric acid  gives  with  platinum  chloride  a  double  salt  which  is  insoluble  in 
alcohol,  soluble  in  ether,  and  which  contains  10.2^  platinum. 

'  See  Stoklasa,  Ber.  d.  deutsch.  cbem.  Gesellsch.,  Bd.  29 ;  Wiener  Sitzungsber.,  Bd. 
104;  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  25;  and  "W.  Danielewsky,  Comp.  rend.,  Tome  121 
and  123. 

'  Zeitschr,  f.  pbysiol.  Chem.,  Bd.  12. 


PREPAliATlON  OF  LECITHIN.  106 

It  may  be  propareil  tolerably  pure  from  the  yolk  of  the  hen's  egg  by  the 
following  methods,  as  suggested  by  Hoite-Skylkk  and  Diaconow.  The 
yolk,  deprived  of  proteid,  is  extracted  with  cold  ether  until  all  the  yellow 
color  is  removed.  Then  the  residue  is  extracted  with  alcohol  at  oO-fJO"  C. 
After  the  evaporation  of  the  alcoholic  extract  at  50-(>0°  C,  the  sirupy 
matter  is  treated  with  ether  and  the  insoluble  residue  dissolved  in  as  little 
alcoliol  as  possible.  On  cooling  this  filtered  alcoholic  solution  to  —  5°  to 
—  10°  C.  the  lecithin  gradually  separates  in  small  granules.  The  ether, 
however,  contains  considerable  of  the  lecithin.  The  ether  is  distilled  off 
and  the  residue  dissolved  in  chloroform  and  the  lecithin  precipitated  from 
this  solution  by  means  of  aceton  (Altmaxn  '). 

According  to  Gilsox,  a  new  portion  of  lecithin  may  be  obtained  from 
the  ether  used  in  extracting  the  yolk  by  dissolving  the  residue  after  the 
evaporation  of  the  ether  in  petroleum  ether  and  then  shaking  this  solution 
with  alcohol.  The  petroleum  ether  takes  the  fat,  while  the  lecithin  remains 
dissolved  in  the  alcohol  and  may  be  obtained  therefrom  rather  easily  by 
using  the  proper  precautions. 

The  detection  and  the  quantitative  estimation  of  lecithin  in  animal 
fluids  or  tissues  is  based  on  the  solubility  of  the  lecithin  (at  oO-GO°  C.)  in 
alcohol-ether,  by  which  the  phosphoric  acid  or  glycerophosphoric  acid  salts 
which  may  be  present  at  the  same  time  are  not  dissolved.  The  alcohol- 
ether  extract  is  evaporated,  the  residue  dried  and  fused  with  soda  and  salt- 
petre. Phosphoric  acid  is  formed  from  the  lecithin,  and  it  can  be  used  in 
the  detection  and  quantitative  estimation.  The  distearyllecithin  yields 
8.798^  1\0,.  This  method  is,  however,  not  exactly  correct,  for  it  is 
possible  that  other  phosphorized  organic  combinations,  such  as  jecorin  (see 
Chapter  VIII)  and  protagon  (Chapter  XII)  may  have  passed  into  the 
alcohol-ether  extract.  In  detecting  lecithin  the  double  combination  of 
cholin  and  platinum  must  also  be  prepared.  The  residue  of  the  evaporated 
alcohol-ether  extract  may  be  boiled  for  an  hour  with  baryta-water,  filtered, 
the  excess  of  barium  precipitated  with  CO,,  and  filtered  while  hot.  The 
filtrate  is  concentrated  to  a  sirupy  consistency,  extracted  with  absolute 
alcohol,  and  the  filtrate  precipitated  with  an  alcoholic  solution  of  platinum 
chloride.  The  precipitate  after  filtration  may  be  dissolved  in  water  and 
allowed  to  crystallize  over  sulphuric  acid. 

Protagons,  which  are  found  in  the  leucocytes  and  pus-cells,  are  also  to 
be  considered  as  a  constituent  of  protoplasm.  These  phosphorized  bodies 
occur  principally  in  the  brain  and  nerves,  and  hence  will  be  described  in  a 
following  chapter. 

Glycogen,  discovered  by  Cl.  Bernard  and  Hensen",  is  found  in  devel- 
oping animal  cells  and  especially  in  developed  embryonic  tissues.  Accord- 
ing to  IIoppe-Seyler  it  seems  to  be  a  never-failing  constituent  of  the  cells, 
which  show  amoeboidal  movement,  and  he  found  this  carbohydrate  in  the 
leucocytes,  but  not  in  the  developed  motionless  pus-corpuscles.  Salomox 
and  afterwards  others  have,  however,  found  glycogen  in  pus."     From  the 

'  Cited  from  Hoppe-Seyler's  Hanfibuch,  etc.,  6.  Aufl.,  S.  84. 
'  In  regard  to  the  literature  on  glycogen  see  Chap.  VIII. 


106  THE  ANIMAL   CELL. 

relationship  which  seems  to  exist  between  glycogen  and  mnscnlar  work  (see 
Chapter  XI),  it  is  presnmable  that  a  consumption  of  glycogen  takes  place 
in  the  movement  of  animal  protoplasm.  On  the  other  hand,  the  extensive 
occurrence  of  glycogen  in  embryonic  tissues,  as  also  its  occurrence  in  patho- 
logical tumors  and  in  abundant  cell-formation,  speaks  for  the  importance  of 
this  body  in  the  formation  and  development  of  the  cell. 

In  adult  animals  glycogen  occurs  in  the  muscles  and  certain  other 
organs,  but  principally  in  the  liver;  therefore  it  will  be  completely  described 
in  connection  with  this  organ  (Chapter  VIII).  Glycogen  has  been  directly 
detected  as  a  constituent  of  the  protoplasm  of  various  cells. 

Another  body,  or  perhaps  more  correctly  a  group  of  bodies  which  occur 
widely  distributed  in  the  animal  and  vegetable  kingdoms,  and  which  occur 
regularly  in  the  cells,  are  the  cholesterins.  The  best-known  representative 
of  this  group  is  ordinary  cholesterin  (see  Chapter  VIII),  which  is  the  chief 
constituent  of  certain  biliary  calculi  and  exists  in  abundant  quantities  in  the 
brain  and  nerves.  It  is  hardly  admissible  that  this  body  is  of  direct 
importance  for  the  life  and  development  of  tbe  cell.  It  must  be  considered 
that  the/cholesterin,  as  accepted  by  Hoppe-Seyler,'  is  a  cleavage  product 
appearing  in  the  cell  during  the  processes  of  life.  According  to  Hoppe- 
Seyler  the  same  is  true  for  the  fats,  Avhich  do  not  occur  constantly  in  the 
cells  and  have  nothing  to  do  in  the  ordinary  processes  of  life.  There  is  no 
doubt  that  cholesterin  exists  as  a  constituent  of  the  protoplasm,  but  its 
existence  in  the  nucleus  is  questionable. 

The  cell  nucleus  has  a  rather  complex  structure.  It  consists  in  part  of 
a  mit02)lasm,  which  consists  of  fibriles  which  form  a  network,  and  another 
part,  which  is  less  solid  and  homogeneous,  called  the  liyaloplasm.  The 
mitoplasm  differs  from  the  hyaloplasm  in  a  stronger  affinity  for  many  dyes. 
On  account  of  this  behavior  the  first  is  called  the  chromatic  substance  or 
chromatin.,  and  the  other  the  achromatic  substance  or  achromatin. 

The  hyaloplasm  of  the  nucleus  is  considered  as  a  mixture  of  proteid. 
The  mitoplasm  seems  to  contain  the  more  specific  constituent  of  the  nucleus, 
namely,  the  nuclein  substances.  •  Besides  tliis  it  is  alleged  to  also  contain 
another  substance,  ^^^astin.  This  last  is  less  soluble  than  the  nuclein  sub- 
stances and  does  not  have  the  property,  like  them,  of  fixing  dyes. 

The  chief  constituents  of  the  cell  nucleus  are  tlie  nucleoproteids 
(midems),  and  in  a  few  cases  nucleic  acids. 

Nucleins.  By  the  name  nuclein  IIoppe-Setler  and  Miescher  '  desig- 
nated tlie  chief  constituent  of  the  nucleus  of  the  pus-cell  first  isolated  by 
MiESciiEii.  Since  it  has  been  shown  by  repeated  research  that  similar 
bodies  occur  extensively  in  the  animal  and  plant  kingdoms,  especially  in 

'  Physiol.  Chem.,  S.  81. 

'  Hoppe-Seyler,  Med. -chem.  Untersuch.,  S.  452. 


PSEUDONUCLEINS.  107 

organs  rich  in  cells,  we  have  for  some  time  designated  as  nncleins  a  nnmher 
of  phosphorized  bodies  whicli  are  in  part  derived  as  cleavage  products  from 
the  nncleoalbumins  and  in  part  form  the  chief  constituent  of  the  cell 
nucleus. 

According  to  IIoppe-Seyler,  these  bodies  may  be  divided  into  three 
groups.  The  first,  to  which  belongs  the  nuclein  of  yeast,  pus,  nucleated 
red  blood-corpuscles,  and  probably  of  the  cell  nucleus  in  general,  yield 
proteid  bodies,  xanthin  bodies,  and  phosphoric  acid  as  cleavage  i)roducts  on 
boiling  with  acids.  To  the  second  group,  which  yield  as  splitting  products 
proteid  and  phosphoric  acid,  but  no  xanthin  bodies,  belongs  the  nuclein  of 
the  yolk  of  the  e^g  and  casein — in  other  words,  the  nucleo-albumins  in 
general;  and  to  the  third  group,  which  gives  as  splitting  products  only 
phosphoric  acid  and  xanthin  bodies,  but  no  proteid,  belongs  only  the  nuclein 
of  spermatozoa. 

Those  nuclein  substances  which  do  not  yield  nuclein  bases  on  splitting 
— such,  for  instance,  as  nuclein  from  casein  and  vitellin — are  to  be  separated 
from  the  others.  Kossel  has  suggested  the  name  paj'a7iuclci)i  for  these 
nuclein  substances.  As  the  paranucleins  amongst  themselves  are  very 
different  and  have  only  an  apparent  similarity  to  the  true  nucleius,  the 
author  has  proj^osed  the  name pseudonucleins  for  them.' 

The  nuclein  of  spermatozoa,  which  does  not  yield  any  proteid  on 
cleavage,  shows  a  great  similarity  to  the  substance  obtained  by  Altmaxx 
from  the  nucleins  of  IIoppe-Seyler's  first  group  by  the  action  of  alkalies. 
This '  substance  was  called  nucleic  acid  by  Altsianx 'and  Kossel,"  and 
hence  this  nuclein  will  be  called  nucleic  acid  in  the  future. 

The  nuclein  of  the  first  group  is,  according  to  Kossel,  true  nuclein  or 
simply  nuclein.  This  nuclein,  which  gives  phosphoric  acid  as  well  as 
proteid  and  xanthin  bases  on  splitting  with  acids,  is  considered  by  Kossel 
as  a  combination  between  proteid  and  nucleic  acid. 

We  therefore  have  two  chief  groups  of  nucleins:  pseudonucleins  or 
paranucleins,  which  yield  no  nuclein  bases  (xanthin  bodies)  as  cleavage 
products  and  corresponding  thereto,  do  not  contain  any  nucleic  acid,  and 
true  nucleins,  or  simply  nucleins^  the  combination  of  proteid  with  nucleic 
acid  whicli  give  xanthin  bodies  as  cleavage  products. 

Pseudonucleins  or  Paraxucleixs.  These  bodies  are  obtained  as  an 
insoluble  residue  on  the  digestion  of  nncleoalbumins  or  phosphoglyco- 
proteids  with  pepsin  hydrochloric  acid.  Attention  is  called  to  the  fact  that 
the  pseudonuclein  may  be  dissolved  by  the  presence  of  too  much  acid  or  by 
a  too  energetic  peptic  digestion.     If  the  relationship  between  the  degree  of 

'  Kossel,  Du  Bois-Reymond's  Arch.,  1891  ;  Hamraai-sten,  Zeitschr.  f.  physiol.  Cheni., 
Bd.  19. 

'  Altinann,  Du  Bois-Reymond's  Arch..  1889;  Kossel,  ibid.,  1891. 


108  THE  ANIMAL   CELL. 

acidity  and  the  quantity  of  substance  is  not  properly  selected  the  formation 
of  pseudonucleins  may  be  entirely  overlooked  in  the  digestion  of  certain 
nucleoalbumins.  Pseudonucleins  contain  phosphorus,  which,  as  shown  by 
LiEBEKMANN,'  is  Split  off  as  mctaphosphoric  acid  by  mineral  acids.  The 
pseudonucleins  are  very  dissimilar.  One  gronp  of  these,  whose  most 
important  representative  is  the  long-known  psendonuclein  from  casein, 
yields  no  reducing  substance  on  boiling  with  mineral  acids,  while  the  other 
gronp,  to  which  the  psendonuclein  from  ichthulin  belongs,  does  yield  such 
a  substance. 

As  we  consider  the  true  nucleins  as  a  combination  of  proteid  with 
nncleic  acid  so  the  pseudonucleins  may  be  designated  as  a  combination  of 
joroteid  and  a  special  acid  called  pseudo-  or  paranncleic  acid.  Such  an  acid 
of  characteristic  properties  has,  up  to  the  present  time,  not  been  prepared.^ 

The  pseudonucleins  are  amorphous  bodies  insoluble  in  water,  alcohol, 
and  ether,  but  readily  soluble  in  dilute  alkalies.  They  are  not  soluble  in 
very  dilute  acids,  and  may  be  precipitated  from  their  solution  in  dilute 
alkalies  by  adding  acid.     They  give  the  proteid  reactions  very  strongly. 

In  preparing  a  psendonuclein,  dissolve  the  mother-snbstance  in  hydro- 
chloric ^cid  of  1-2  p.  m.,  filter  if  necessary,  and  add  pepsin  solution,  and 
allow  to.  stand  at  the  temperature  of  the  body  for  about  24:  hours.  The 
precipitate  is  filtered  off,  washed  with  water,  and  jDurified  by  alternately 
dissolving  in  very  faintly  alkaline  water  and  reprecipitating  with  acid. 

The  true  nucleins  first  prepared  by  Miescher  and  Hoppe-Seyler  are 
not  native  constitjients  of  the  cell,  but  laboration  jirodncts,  which  are 
derived  from  the  native  nucleoproteids  by  the  j^epsin  digestion  or  by  not 
too  energetic  action  of  the  acid.  A  part  of  the  proteid  is  hereby  split  off 
from  the  native  nucleoproteid  and  the  insoluble  residue  poor  in  proteid  but 
rich  in  nucleic  acid  forms  the  so-called  nuclein.  If  we  consider,  according 
to  IIoppe-Seyler,  as  compound  proteids  all  substances  which  yield  as 
cleavage  products  proteids  and  another  non-proteid  component,  then  we  must 
also  treat  the  true  nucleins  as  nucleoproteids.  There  are  modified  nucleo- 
proteids which  differ  from  the  native  compound  proteids  in  containing  a 
greater  amount  of  phosphorus,  or  nucleic  acid.  Strictly  speaking,  all  true 
nucleins  are  nucleoproteids,  and  for  this  reason  it  is  perhaps  best  to  drop  the 
name  nucleins,  which  unfortunately  is  used  in  various  senses,  and  only 
differentiate  between  native  and  modified  nucleoproteids.  As  from  another 
standpoint,  it  is  probably  best  to  wait  until  we  have  further  information  in 
regard  to  the  nature  of  the  nuclein  substances  before  we  undertake  a  change 
in   the  nomenclature,  we  will  here  designate  as  true  nucleins   or   simply 

'  Ber.  d.  deutsch.  chem.  Gesellscb.,  Bd.  21,  and  Centralbl.  f.  d.  med.  Wissensch., 
1889. 

*  See  Milroy,  Zeitschr.  f.  physiol.  Chem.,  Bd.  22,  and  Proc.  ^oy.  Soc.  of  Edinburgh, 
189G. 


NUCLEIC  ACIDS.  109 

nucleins  those  modified  nucleoproteids  insoluble  in  digestion  hydrochloric 
acid.  This  will  hardly  lead  to  any  misunderstanding.  According  to  this 
nomenclature  the  native  nucleoproteids  correspond  to  the  nucleoalbumius 
und  the  nucleins  correspond  to  the  pseudonncleins,  which  are  modified 
nucleoalbuminsrich  in  pliosphorus.  Tiie  properties  of  the  different  nucleo- 
proteids and  nucleins  are  undoubtedly  in  part  dependent  upon  the  kind  of 
proteid  component.  To  all  appearances  the  nature  of  the  nucleic  acid 
component  is  of  still  greater  importance  and  for  this  reason  the  nucleic 
acids  will  be  treated  of  first.  The  nucleoproteids  will  then  follow  and 
finally  the  nucleins. 

Nucleic  Acids.  "We  differentiate  between  the  various  nucleic  acids  by 
the  decomposition  products  they  yield.  All  are  rich  in  phosphorus  and 
yield  micleiti  bases  (purin  bases  according  to  E.  Fischer)  as  cleavage 
products.  Various  nucleic  acids  act  different  in  this  regard.  The  nucleic 
acid  from  ox-sperm  yields,  according  to  Kossel  almost  entirely  xanthin, 
while  that  from  the  calf  thymus  yields  chiefly  adenin  with  only  a  little 
guanin.  Kossel  used  to  be  of  the  opinion  that  there  were  probably  four 
nucleic  acids,  each  containing  only  one  of  the  nuclein  bases,  thus  an 
adenylic,  a  guanylic  acid,  etc.  He  has  now  given  up  this  view  in  so  far 
as  the  nucleic  acid  from  the  thymus,  in  which  he  only  found  adenin, 
contains  some  guanin.  For  this  reason  he  does  not  call  this  acid  adenylic 
acid  but  thymus  micleic  acid.^  That  wo  have  nucleic  acids  which  only 
contain  one  nuclein  base  follows  from  the  nucleic  acid  isolated  by  Baxg  ' 
frem  the  pancreas,  guanylic  acid,  which  contains  guanin  only  and  indeed 
about  30^.  "We  must  differentiate  between  several  nucleic  acids  depending 
upon  the  nuclein  bases  contained  therein.  "We  must  also  still  admit  of 
different  nucleic  acids  from  another  jaoint  of  view.  There  are  some,  as  the 
nucleic  acid  from  the  pancreas  and  the  yeast  nucleic  acid,  which  contains  a 
relatively  loosely  combined  carbohydrate  group,  which  is  readily  split  off. 
Others,  on  the  contrary,  such  as  the  thymus  nucleic  acid  and  nucleic  acid 
from  the  salmon-sperm,  sahnoii  nucleic  acid,  no  carbohydrate  can  be  split 
off.  Only  on  energetic  cleavage  have  Kossel  and  Xeumanx  been  able  to 
obtain  levulinic  acid  from  thymus  nucleic  acid,  which  is  proof  of  the  pres- 
ence of  a  carbohydrate  group.  Noll'  has  also  split  off  levulinic  acid  from 
the  nucleic  acid  of  sturgeon- sperm.  According  to  Xkumaxn*  thymus 
nucleic  acid  is  not  a  unit,  but  consists  of  mixture  of  three  acids  which  he 

'  The  works  of  Kossel  and  his  pupils  on  nucleic  iicids  are  found  in  Du  Bois-Itey- 
mond's  Arch.,  1892,  1893,  and  1894;  Sitzungsber.  d.  Berl.  Akad.  d.  Wissensch.,  18. 
1894;  Centralbl.  f.  d.  nied.  Wissensch.,  1893;  Bar.  d.  deutsch.  chem.  Gesellsch.,  Bdd. 
26  and  27  ;  Zeitscbr.  f.  physiol.  Chem..  Bd.  22. 

'  Investigations  not  published  from  the  Author's  laboratory. 

^  Zeitscbr.  f.  physiol.  Chem.,  Bd.  25. 

«  Du  Bois-Reymond's  Arch.,  1898,  S.  374. 


110  THE  ANIMAL   CELL. 

has  designated  A  and  B  nucleic  acid  and  nacleothymic  acid.  The  two 
nncleic  acids  correspond  in  properties  essentially  with  the  substance,  which 
used  to  be  designated  nncleic  acid.  Nacleothymic  acid  can  be  split  off 
from  both  by  hydrolytic  cleavage.  Nucleothyniic  acid,  which  differs  from 
the  real  nncleic  acids  in  being  readily  sol  able  in  cold  water,  yields  thyniin., 
cytosin,  phosphoric  acid,  levnlinic  acid  and  formic  acid  as  cleavage  products. 
All  three  nucleic  acids  gives  Tollexs'  pentose  reaction. 

The  nucleic  acids  are  very  different  among  each  other  and  corresponding 
thereto  they  have  also  a  varying  composition.  They  are  all  free  from 
Bulphur  but  contain  nitrogen  and  jihosphorus.  The  relationship  between 
phosphorus  and  nitrogen  in  the  nncleic  acids  from  the  thymus,  salmon- 
sperm  and  yeast  is  as  1  :  3,  in  guanylic  acid  as  1  :  5.  Nothing  is  known 
with  positiveness  in  regard  to  the  form  of  union  of  the  phosphorus.' 

The  cleavage  products  of  the  nucleic  acids  are  also  different.  From 
guanylic  acid  Bang  obtained  on\j pentose,  while  on  the  contrary  Kossel 
obtained  pentose  as  well  as  liexose  from  yeast  nucleic  acid,  and  from  salmon 
nucleic  acid  or  that  from  the  thymus  neither  one  nor  the  other  sugar  could 
be  prep^ed.  According  to  Kossel  and  Neumann"  thymus  nucleic  acid 
yields  as  cleavage  products,  besides  adenin  and  guanin,  thymic  acid  and  a 
crystalline  base,  cytosin,  with  the  probable  formula,  CjjHj^NjgO^.  The 
thymic  acid,  which  is  readily  soluble  in  water,  and  which  yields  a  barium 
salt  with  the  formula,  0^^153^31*2^12^'^'  soluble  in  water  and  precijiitated 
by  alcohol,  yields  a  cleavage  product,  thymin,  C^HgN^Oj,  which  is  crystal- 
line and  not  precipitatable  by  phospho-tungstic  acid,  and  which  is  charac- 
terized by  its  property  of  being  sublimed.  Thymin  occurs  as  cleavage 
products  from  other  nucleic  acids  (with  the  exception  of  guanylic  acid)  and 
is  identical  with  nucleosin,  prepared  by  Schmiedeberg  from  salmon  nucleic 
acid.  Guanylic  acid,  on  the  contrary,  yields  no  thymin  as  a  cleavage 
product.  It  yields  guanin  (36^),  pentose  (30^)  phosphoric  anhydride, 
PjO,  (IS,'^)  and  a  little  ammonia.  Bang  found  90^  of  tVie  nitrogen 
as  guanin. 

The  composition  of  salmon  nucleic  acid  may,  according  to  Miescher 
and  Schmiedeberg,''  be  represented  ly  the  formula,  C,„H^^N,^Oj,.2P50^, 
and  yeast  nucleic  acid  by  C^„II^„N,^0„.2P,0^.  The  composition  of  guanylic 
acid  seems  to  be  C„Il3,N,„0,,.P,0,. 

The  nucleic  acids  are  amorphous,  white  and  acid  in  reaction.  They  are 
readily  soluble  in  ammoniacal  or  alkaline  water.  Guanylic  acid  is  soluble 
with  difficulty  in  cold  water  but  rather  readily  in  boiling  water,  from  which 
it  separates  on  cooling.     Guanylic  acid  is   readily  precipitated   from   its 

'  Besides  the  works  of  Kossel,  see  also  tliose  of  Liebermann  in  PflUger's  Arch.,  Bd. 
47,  and  Centralbl.  f.  d.  med.  Wissensdi.,  1893,  8.  465  and  738. 
«  Arch.  f.  exp.  Path.  u.  Phurm.,  Bd.  37. 


PREPARATION  OF  NUCLEIC  ACIDS.  Ill 

alkali  combination  by  an  excess  of  acetic  acid.  The  other  nucleic  acids  are, 
on  the  contrary,  not  precipitated  from  snch  combinations  by  an  excess  of 
acetic  acid,  but  by  a  slight  excess  of  liydrochloric  acid,  especially  in  the 
presence  of  afcohol.  In  acid  solutions  the  thymus  nucleic  acid,  salmon 
nucleic  acids,  and  yeast  nucleic  acid  gives  precipitates  with  proteids,  which 
are  considered  as  nucleins.  The  behavior  of  guanylic  acid  in  this  regard 
has  not  been  shown  on  account  of  the  great  difficulty  in  dissolving  this 
acid  in  dilute  acids.  All  nucleic  acids  are  insoluble  in  alcohol  and  ether. 
They  do  not  give  either  the  biuret  test  nor  Millon's  reaction. 

Yeast  nucleic  acid  may  be  best  prepared  according  to  Altmaxx.' 
Each  1000  c.c.  of  yeast  is  treated  with  3250  c.c.  dilute  caustic  soda  of  about 
3^  for  five  minutes  at  the  temperature  of  the  room.  The  chief  portion  of 
the  sodium  hydrate  is  then  neutralized  with  hydrochloric  acid,  and  then 
acetic  acid  added  in  excess.  The  liquid  separated  from  the  precipitated 
proteids  is  acidified  with  hydrocliloric  acid  until  it  contains  3-5  p.  m.  HCl, 
and  then  mixed  with  an  equal  volume  of  alcohol  of  the  same  acidity. 
Impure  nucleic  acid  separates  out  and  may  be  purified  by  dissolving  in 
ammoniacul  water  and  repeatedly  treating,  as  above,  with  acetic  acid, 
hydrochloric  acid,  and  alcohol. 

The  method  of  preparing  tliymus  nucleic  acid,  as  suggested  by  Kossel,* 
is  chiefly  as  follows:  The  nucleohiston  (see  below)  of  the  watery  extract  of 
the  gland  is  split  by  baryta-water  and  the  barium  precipitate  boiled  with 
Avater  containing  acetic  acid  and  the  nucleic  acid  precipitated  from  the 
filtered  watery  extracts  by  alcohol  containing  hydrochloric  acid.  It  may  be 
purified  by  solutioTi  in  water,  containing  1  p.  m.  ammonia  and  reprecipita- 
tion  with  alcohol  containing  hydrochloric  acid. 

Salmon  nucleic  acid,  which  exists  in  the  salmon-sperm  in  combination 
with  the  base  protamin,  is  obtained,  according  to  Miesciieu  and  Sciimiede- 
BERG,  by  extracting  (cooling  at  the  same  time)  with  hydrochloric  acid  of 
5  p.  m.,  which  dissolves  the  protamin.  The  residue  is  then  extracted  by  a 
slight  excess  of  caustic  soda,  cooled  to  0°  C,  and  filtered,  precipitated  with 
hydrochloric  acid  and  alcohol,  the  precipitate  removed  quickly  by  means  of 
centrifugal  force,  and  washed  with  alcohol.  The  principle  of  the  prepara- 
tion of  guanylic  acid  is,  according  to  Bang,  to  split  the  pancreas  nucleo- 
proteids  by  heating  with  dilute  alkali,  filtering  while  hot,  precipitating  the 
nucleic  acid  by  cooling  the  very  faintly  acidified  liquid.  If  necessary, 
concentrate  the  fluid  slightly.  The  nucleic  acid  may  be  purified  by  repeated 
solutioii  in  hot  water  and  precipitating  by  cooling  or  by  repeated  solution 
in  alkaline  water  and  reprecipitating  with  acetic  acid. 

Nucleoproteids  with  relatively  high  percentage  of  phosphorus  and  of  a 
markedly  acid  character  occur  in  cell  nuclei.  According  to  the  generally 
accepted  view  they  are  combinations  of  proteids  with  nucleic  acid  and  yield 
cleavage  products  depending  upon  the  different  nucleic  acid  present.  They 
contain  relatively  considerable  proteid  in  the  molecule  and  hence  respond 

•  Du  Bois-Reymond's  Arch.,  1889,  Physiol.  Abtb.,  S.  524. 
'  Ber.  d.  deutscb.  chem.  Gesellsch.,  Bd.  27.  S.  2215. 


112  THE  ANIMAL   CELL. 

to  the  ordinary  proteid  reactions  and  therefore  are  closely  related  "to  the 
proteids  in  their  behavior.  The  native  nncleoproteids  are  very  sensitive  to 
chemical  agents,  even  distilled  water,  and  are  therefore  readily  changed  by 
the  action  of  the  bodies  used  in  their  isolation.  This  is  the  essential  reason 
why  onr  knowledge  of  the  native  proteids  is  at  present  so  limited.  The 
closest  studied  of  the  native  nncleoproteids  is  the  so-called  nucleohiston. 

Nucleohiston  is  the  name  given  by  Kossel  and  Lilienfeld*  to  the 
nncleoproteid  isolated  by  them  from  the  calf's  thymus.  Its  composition  is: 
C  48.46;  H  7.00;  N  16.86;  P  3.025;  S  0.701;  0  23.95^.  On  heating  its 
solution  it  splits  into  coagulated  proteid.  On  peptic  digestion  it  yields 
nuclein.  On  treating  with  hydrochloric  acid  of  0.8^  it  splits  into  nuclein 
and  a  proteid  substance  soluble  in  hydrochloric  acid,  and  which  differs  from 
other  proteids  in  being  insoluble  in  an  excess  of  ammonia.  Kossel  has 
called  this  substance  Mston. 

Nucleohiston  is  precipitated  from  a  neutral  solution  by  means  of  acetic 
acid,  and  is  not  redissolved  by  an  excess  of  acetic  acid.  The  neutral  solu- 
tion is  precipitated  by  alcohol,  but  not  on  saturating  with  MgSO^.  Nucleo- 
histon is  easily  dissolved  in  dilute  alkalies  or  alkali  carbonates.  It  is  soluble 
in  glacial  acetic  acid,  hydrochloric  and  sulphuric  acids.  The  relationship  of 
the  nucleins  and  histon  to  the  coagulation  of  the  blood  will  be  spoken  of  in 
Chapter  VI. 

Nucleohiston  is  prepared  by  precipitating  the  filtered  watery  extract  of 
the  gland,  free  from  cellular  elements,  with  acetic  acid,  and  purifying  by 
repeated  solution  in  water  slightly  alkaline  with  soda  and  precipitating  with 
acetic  acid.  Finally  it  is  washed  with  water  containing  acetic  acid  and  then 
with  alcohol,  then  extracted  with  cold  and  hot  absolute  alcohol  and  lastly 
with  ether.  The  same  procedure  is  resorted  to  in  the  preparation  of  the 
native  nncleoproteids  in  general,  but  often  with  success,  extracting  with 
water  containing  0.5  p.  m.  ammonia. 

Tbe  compound  proteids-  described  by  other  investigators  under  the  names  tissue 
fibrinofjen  and  cell  fibvinor/i'n  are  to  be  considered  as  impuie  nucleohiston  or  bodies  very 
closely  related  thereto.  The  oytoglobin  and  'preglobuliu  described  by  Alex.  Schmidt  ^  as 
important  cell  constituents  also  belong  to  the  same  group  as  tiie  nucleohiston.  Cytoglo- 
bin  is  to  be  considered  as  the  alkali  combination  of  preglobulin.  The  residue  remaining 
on  tlie  complete  exhauslion  of  the  cells  with  alcohol,  water,  and  common-suit  solution  is 
called  cytin  by  Alex.  Schmidt.  The  relationship  of  these  bodies  to  the  coagulation  of 
blood  will  be  spoken  of  in  Chapter  VI. 

Nucleins  or  True  Nucleixs.     These  bodies  are  obtained  as  an  insoluble 

or  difficultly  soluble  residue  on  the  digestion  of  nucleoproteids  with  pepsin 

hydrochloric  acid.     They  are  rich  in  phosphorus,  about  5^  and  above,  and 

according  to  Liebermaxn  '  metaphosphoric  may  also  be  split  off  from  the 

true  nucleins  (yeast  nuclein).     The  nucleins  are  decomposed  into  proteid 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

«  See  page  101. 

2  Zur  Blutlehre. 

*  Pflueer's  Arch..  Bd.  47. 


TRUE  NUCLEIN8.  1 1 3 

and  nucleic  acid  by  caustic  alkali,  ami  as  dilTerent  nucleic  acids  exist,  so 
there  also  exist  difTerent  nncleins.  As  previously  stated,  proteids  may  be 
precipitated  in  acid  solutions  by  nucleic  acids  and  in  this  way,  as  shown  by 
MiLROY,'  combinations  of  nucleic  acid  and  proteids  may  be  prepared  which 
behave  quite  similar  to  true  nucleius.  All  nucleins  yield  xanthin  bodies  or 
nuclcin  bases,  so  called  by  Kossel,  on  boiling  witli  dilute  acids.  The 
nncleins  contain  iron  to  a  considerable  extent.  They  act  like  rather  strong 
acids. 

The  nucleins  are  colorless,  amorphous,  insoluble,  or  only  slightly  soluble 
in  water.  They  are  insoluble  in  alcohol  and  ether.  They  are  more  or  lesp 
readily  dissolved  by  dilute  alkalies.  Pepsin  hydrochloric  acid  or  dilute 
mineral  ac'ds  do  not  dissolve  them,  or  only  to  a  slight  extent.  The 
nucleins  give  the  biuret  test  and  Millon's  reaction.  They  show  a  great 
affinity  for  many  dyes,  especially  the  basic  ones,  and  take  these  up  with 
avidity  from  watery  or  alcoholic  solutions.  On  burning  they  yield  an  acid 
coke  containing  metaphosphoric  acid  and  which  is  very  difficult  to  consume. 
On  fusion  with  saltpetre  and  soda  the  nucleins  yield  alkali  phosphates. 

To  prepare  nucleins  from  cells  or  tissues,  first  remove  the  chief  mass  of 
proteids  by  artificial  digestion  with  pepsin  hydrochloric  acid,  lixiviate  the 
residue  with  very  dilute  ammonia,  filter,  and  precipitate  with  hydrochloric 
acid.  The  precipitate  is  further  digested  with  gastric  juice,  washed  and 
purified  by  alternately  dissolving  in  very  faintly  alkaline  water,  and 
reprecipitating  with  an  acid,  washing  with  water,  and  treating  with  alcohol- 
ether.  A  nuclein  may  be  prepared  more  simply  by  the  digestion  of  a 
nucleoproteid.  In  the  detection  of  nucleins  we  make  use  of  the  above- 
described  method  and  testing  for  phosphorus  in  the  product  after  fusing 
with  saltpetre  and  soda.  Naturally  the  phosphates,  lecithins  (and  jecorin) 
must  first  be  removed  by  treatment  with  acid,  alcohol,  and  ether,  respect- 
ively. We  must  specially  call  attention  to  the  fact,  as  shown  by  Lieber- 
MAXN,"  of  the  very  great  difficulty  in  removing  lecithin  by  means  of 
alcohol-ether.  No  exact  methods  are  known  for  the  quantitative  estimation 
of  nucleins  in  organs  or  tissues. 

Plastin.— On  the  solution  of  the  nucleins  from  cell  nuclei  of  certain  plants  in  dilute 
soda  solution  a  residue  is  obtained  which  is  characterized  by  its  great  insolubilit^^  The 
substance  which  forms  this  residue  has  been  called  plastin.  This  substance,  of  which 
the  spongioplasm  of  the  body  of  the  cell  and  the  nucleus  granules  are  alleged  to  be  com- 
posed, is  considered  as  a  nuclein  moditication  of  great  insolubility,  although  its  nature  is 
not  known. 

Among  the  decomposition  products  of  nuclein  substances  the  nuclein 
bases  or  xanthin  bodies  are  of  especially  great  interest. 

Nuclein  bases,  Alloxuric  bases,  purix  bases,  xaxthix  bodies.  "With 
these  names  we  designate  a  group  of  bodies  consisting  of  carbon,  hydrogen, 
nitrogen,  and  in  most  cases  also  of  oxygen,  which,  by  their  composition, 
show  a  relationship  not  only  among  themselves,  but  also  with  uric  acid. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  23. 
'PflUger's  Arch.,  Bd.  54. 


114  TEE  ANIMAL   CELL. 

All  these  bodies,  uric  acid  included,  are  considered  as  consisting  of  an 
alloxnric  and  an  nrea  nucleus,  and  for  this  reason  Kossel  and  Krugek  have 
called  them  alJoxuric  bases,  or  the  entire  group,  including  uric  acid,  alloxuric 
bodies.  According  to  E.  Fischer,'  who  has  not  only  shown,  in  several 
tvays,  the  close  relationship  of  uric  acid  to  this  group,  but  has  also  prepared 
a  number  of  the  members  of  this  group  synthetically,  they  are  all  derived 
from  a  combination  C^H^N^,  j^urin,  having  a  carbon-nitrogen  nucleus, 
the  purin  nucleus,  as  basis.  Purin.  according  to  Fischer,  has  the  formula, 
X=OH 

I  \ 

HC         C— ^TH 

II  II  /  CH,  and  the  different  purin  bodies  are  derived  therefrom 
X—    C—  X  '^ 

by  the  substitution  of  the  various  hydrogen  atoms  by  hydroxyl,  amid,  or 
alkyl  groups.  In  order  to  signify  the  different  positions  of  substitution 
Fischer  has  proposed  to  number  the  nine  members  of  the  purin  nucleus  in 
the  following  way: 

/  IN— C6 

/  I 

30  5C— N7\ 
I       1  >C8. 

4       9 

HN— CO 

I  I 

CO       C— NH. 
For  example :    uric   acid,       1  ||  /CO,      is    2,    6,    8-trioxypurin,    adeuiu 

HN  — C— NH/ 
N=C.NH,  HN-CO 

II  I-     I 

HC     C-NH\  COC-N.CHs 

II      II  ^CH  =  6  amidopurin,  and  heteroxanthin       |       ||        \--,tt  =  7  methyl- 

N_C-  n/  HN-C-N/^^ 

2,  6  dioxypurin,  etc. 

The  starling-point  used  by  Fiboher  for  tlie  synthetical  preparation  of  the  purin  bases 
was  2,  6,  8  irichlorpuriii,  which  is  obtained,  with  8oxy-2,  6-diclilorpurin  as  intermedi- 
ary ]>'ro(lucts,  from  potassium  urate  and  phosphorus  oxychloride.  The  close  relation 
between  uric  acid  and  the  iiuclein  bases  follows  from  the  fact,  as  shown  by  Sundvik,'' 
that  two  bodies  may  be  obtained  on  the  reduction  of  uric  acid  in  alkaline  solution, 
which,  altliouc;h  not  quite  identical  with  xanthin  and  hypoxanthin,  are  at  least  very 
similar  tliereto.  Gautiki:  '  claims  to  have  prepared  xanthin  synthetically  by  heating 
liydrocyanic  acid  with  water  and  acetic  acid.* 

'  See  Fischer,  Ber,  d.  deiitsch.  chem.  Gesellsch.,  Bd.  30. 

«  Zeitschr.  f.  physiol.  Ciiem.,  Bd.  23. 

»  Compt.  rend  ,  Tome  98,  p.  lo23,  and  Ber.  d.  deutsch.  chem.  Gesellsch.,  31. 

*  E.  Fischer  gives  a  very  instructive  summary  and  review  of  his  investigations  on  the 
purin  bodies  and  the  most  important  chemical  facts  in  regard  to  this  subjert  in  Ber.  d. 
deutsch.  chem.  Gesellsch.,  Bd.  32,  S.  585. 


NUCLEIN  BASES.  115 

Tiie  jmria  bodies  or  alloxnric  bodies  found  in  the  animal  body  or  its 
extract  are  as  follows:  uric  acid,  xantliin,  heteroxanthin  (7-methylxanthin), 
\-mellujlxantliin,  paraxanthiii  (1,  7-diniethylxanthin),  f/uaiiiti,  epigiianin, 
hypoxanthin  (sarkiu),  episarkin,  adenin,  and  carnin.  The  bodies,  theo- 
bromin  (3,  7-diniethylxa!ithin),  theophijlin  (1,  3-diniethylxanthiu),  and 
caffeiu  (1,  3,  7-trimethylxantliin)  occurring  in  the  vegetable  kingdom  stand 
in  close  relationship  to  this  group. 

The  composition  of  these  bodies  occuiriiig  iu  the  auimal  body  is  as  follows  : 

Uric  acid C'6H4N403 

Xamhin ClI^NiOj 

Heteroxanthin  and  1-melhylxanthin C„IInN402 

Puiaxanthin CiHeN^Oi 

Guaniu C61I6N60 

Hypoxanthin Cf.H4N40 

Aileniu   CtHsNs 

Episaikiu CMUNaO  (?) 

CMvnin CTH^N^Oa 

Epiguauiu C;,iH,Nj(> 

After  Salomon  had  shown  the  occurrence  of  xanthin  bodies  in  young 
cells  the  importance  of  the  xanthin  bodies  as  decomposition  products  of  cell 
nuclei  and  of  nucleins  was  shown  by  the  pioneering  researches  of  Kossel, 
who  discovered  adenin  and  theophyllin.  Kossel  gave  them  the  name 
nuclein  bases.  In  those  tissues  in  which,  as  in  the  glands,  the  cells  have 
kept  their  original  state  the  nuclein  bases  are  not  found  free,  but  in  com- 
bination with  other  atomic  groups  (nucleins).  In  such  tissue,  on  the 
contrary,  as  in  muscles,  which  are  poor  in  cell  nuclei,  the  nuclein  bases  are 
found  in  the  free  state.  As  the  nuclein  bases,  as  suggested  by  Kossel, 
stand  in  close  relationship  to  the  cell  nucleus,  it  is  easy  to  understand  why 
the  quantity  of  these  bodies  is  so  greatly  increased  when  large  quantities  of 
nucleated  cells  appear  in  such  places  as  were  before  relatively  poorly 
endowed.  As  an  example  of  this  we  have  in  leucnemia  blood  extremely  rich 
in  leucocytes.  In  such  blood  Kossel'  found  1.04  p.  m.  nuclein  bases, 
against  only  traces  in  the  normal  blood.  That  the  nuclein  bases  are  also 
intermediate  steps  in  the  formation  of  urea  or  uric  acid  in  the  animal 
organism  is  probable,  and  will  be  shown  later  (see  Chapter  X\'). 

Only  a  few  of  the  nuclein  bases  have  been  found  in  the  urine  or  in  the 
muscles.  Only  four  bases — xanthin,  guanin,  hypoxanthin,  and  adenin — 
have  been  obtained,  thus  far,  as  cleavage  products  of  nucleins.  In  regard 
to  the  other  purin  bodies  we  refer  the  reader  to  their  respective  chapters. 
Only  the  above  four  bodies,  the  real  nuclein  bases,  will  be  treated  of  at  thia 
time. 


'  Zeitschr.  f.  physiol.  Chem.,  Bd.  7,  S.  22. 


116  THE  ANIMAL   CELL. 

Of  these  four  bodies  the  xanthin  and  guanin  form  one  special  group,  and  hypoxantbin 
and  adeniu  another.  By  the  action  of  nitrous  acid  guaniu  is  converted  into  xanthin  and 
adeuiu  into  hypoxanthin. 

C6H«N40.NH  +  HNO.,  =  C6H4N4O,  +  N,  +  H,0 ; 

Guanin  Xanthin 

C6H4N4.NH  +  HNO.  =  C6H4N4O   +  N2  +  H3O. 

Adenin  Hypoxanthin 

By  putrefaction  guaniu  is  converted  into  xanthin  and  adenin  into  hypoxanthin.  On 
cloavaffe  with  hydrochloric  acid  all  four  of  the  bodies  are  converted  into  ammonia, 
glvcocoll,  carbou  dioxide,  and  formic  acid.  On  oxidation  with  hydrochloric  acid  and 
potassium  chlorate  xanthin,  bromadenin,  and  bromhypoxanthin yield  alloxan  and  urea; 
guanin  yields  guanidin,  parabanic  acid  (an  oxidation  product  of  alloxan),  and  carbon 
dioxide. 

The  nuclein  bases  form  crystalline  salts  with  mineral  acids,  which  are 

decomposed  by  water  with  the  exception  of  the  adenin  salts.     They  are 

easily  dissolved  by  alkalies,  while  with  ammonia  their  action  is  somewhat 

different.     They  are  all  precipitated  from  acid  solution  by  phospho-tnngstic 

acid,  also  they  separate  as  a  silver  combination  on  the  addition  of  ammonia 

and  ammoniacal  silver-nitrate  solution.     These  precipitates  are  soluble  in 

boiling  nitric  acid  of  1.1  sp.  gr.     All  xanthin  bodies  with  the  exception  of 

caff ein  and  theobromin  are  precipitated  by  Fehlikg's  solution  (see  Chapter 

XV)    in/ the   presence   of    a  reducing    substance    such   as  hydroxylamin 

(Drechsel  and  Balke).     Copper  sulphate  and  sodium  bisulphite  may  also 

be  used  to  advantage  in  their  precipitation  (Krugee,  ').     This  behavior  of 

the  xanthin  bases  is  made  use  of  to  the  same  advantage  as  the  silver  solution 

in  their  precipitation  and  preparation. 

HN— CO 

I         I 
CO      C— NHv 

Xanthin,  C5n4N40o  =     |         ||  /)Cn  =  2,  6-dioxypurin,  is  found 

HN— C— N    ^/ 

in  the  muscles,  liver,  spleen,  pancreas,  kidneys,  testicles,  carp-sperm, 
thymus,  and  brain.  It  occurs  in  small  quantities  as  a  physiological  constit- 
uent of  urine,  and  it  has  been  found  rarely  as  a  urinary  sediment  or 
calculus.  It  was  first  observed  in  such  a  stone  by  Marcet.  Xanthin  is 
found  in  larger  amounts  in  a  few  varieties  of  guano  (Jarvis  guano). 

Xanthin  is  amorphous,  or  forms  granular  masses  of  crystals  or  may  also, 
according  to  IIojiuaczewski  ^  separate  as  masses  of  shining,  thin,  large 
rhombic  plates  with  1  mol.  water  of  crystallization.  It  is  very  slightly 
solnble  in  water,  in  11,151-14,600  parts  at  +  1G°  C,  and  in  1300-1500 
parts  at  100°  C.  (Almen  '').  It  is  insoluble  in  alcohol  or  ether,  but  is 
readily  dissolved  by  alkalies  and  with  difficulty  by  dilute  acids.  "With 
hydrochloric   acid   it   gives   a  crystalline,  difficultly   soluble   combination. 

'Balke,   zur  Keiintniss  dcr  Xantliiiikiuper,  Inaug.-Diss.     Leipzig,   1893; — Krilger, 
Zeitschr.  f.  phyisiol.  Chem.,  Bd.  18. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  23. 
'  Journ.  f.  prakt.  Chem  ,  Bd.  96. 


XANTHIN  AND   GUANIN.  117 

With  very  little  caustic  soda  it  gives  a  readily  crystallizable  combination, 
which  is  easily  dissolved  by  an  excess  of  alkali.  Xanthin  dissolved  in 
ammonia  gives  with  silver  nitrate  an  insoluble,  gelatinous  precipitate  of 
xaniiiin  silver.-  This  precijiitate  is  dissolved  by  hot  nitric  acid,  and  bv  this 
means  an  easily  soluble  crystalline  double  combination  is  formed.  A  watery 
xanthin  solution  is  precipitated  on  boiling  with  copper  acetate.  At 
ordinary  temperatures  xantiiin  is  precipitated  by  mercuric  chloride  and  by 
ammoniacal  basic  lead  acetate.  It  is  not  precipitated  with  basic  lead 
acetate  alone. 

When  evaporated  to  dryness  in  a  porcelain  dish  with  nitric  acid  xanthin 
gives  a  yellow  residue,  which  turns,  on  the  addition  of  caustic  soda,  first 
red,  and,  after  heating,  purple-red.  If  we  add  some  chloride  of  lime  to 
some  caustic  soda  in  a  2)orcelain  dish  and  add  the  xanthin  to  this  mixture, 
at  first  a  dark  green  and  then  quickly  a  brownish  halo  forms  around  the 
xanthin  grains  and  then  disappears  (Hoppe-Seyler).  If  xanthin  be 
warmed  in  a  small  vessel  on  tlie  water-bath  with  chlorine-water  and  a  trace 
of  nitric  acid  and  evaporated  to  dryness,  when  the  residue  is  exposed  under 
a  bell-jar  to  the  vapors  of  ammonia  a  red  or  purple-violet  color  is  produced 
(Weidel's  reaction).  E.  Fischer  '  has  modified  Weidel's  reaction  in  the 
following  way.  He  boils  the  xanthin  in  a  test-tube  with  chlorine-water  or 
with  hydrochloric  acid  and  a  little  potassium  chlorate,  then  evaporates  the 
liquid  carefully  and  moistens  the  dry  residue  with  ammonia. 

HN— CO 

Guanin,  0 JI^N^O  =  •H,NC      C— XH 

il^- }\ ^^-^CH  =  2    Amino  -  6  -  oxypurin, 

Guanin  is  found  in  organs  rich  in  cells,  such  as  the  liver,  spleen,  pancreas, 
testicles,  and  in  salmon-sperm.  It  is  further  found  in  the  muscles  (in  very 
small  amounts),  in  the  scales  and  in  the  air-bladder  of  certain  fishes  as 
iridescent  crystals  of  guanin  lime;  in  the  retina  epitlieUum  of  fishes,  in 
guano,  and  in  the  excrement  of  spiders  it  is  found  as  chief  constituent.  It 
also  occurs  in  human  and  pig  urine.  Under  pathological  conditions  it  has 
been  found  in  leucremic  blood,  and  in  the  muscles,  ligaments,  and  articula- 
tions of  pigs  with  guanin  gont. 

Guanin  is  a  colorless,  ordinarily  amorphous  powder  which  may  be 
obtained  as  small  crystals  by  allowing  its  solution  in  concentrated  ammonia 
to  si)ontaneously  evaporate.  According  to  IIorbaczewski  it  may  under 
certain  conditions  appear  in  crystals,  similar  to  ceratinin  zinc  chloride. 
It  is  nearly  insoluble  in  water,  alcohol,  and  ether.  It  is  rather  easily  dis- 
solved by  mineral  acids  and  readily  by  alkalies,  but  it  dissolves  with  great 

"  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  30,  S.  2236. 


118  THE  ANIMAL    CELL. 

difficnlty  in  ammonia.  According  to  Wulff  '  100  c.c.  of  cold  ammonia 
solution  containing  1,  3,  and  5^  NH^  dissolve  9,  15,  and  19  milligrammes 
guanin  respectively.  The  solubility  is  relatively  increased  in  hot  ammonia 
solution.  The  hydrochloric-acid  salt  readily  crystallizes,  and  this  has  been 
recommended  by  Kossel"  iu  the  microscopical  detection  of  guanin  on 
account  of  its  behavior  to  polarized  light.  The  sulphate  contains  2  mols. 
water  of  crystallization,  Avhich  is  completely  expelled  on  heating  to  120°  C, 
and  for  this  reason  as  well  as  the  fact  that  guanin  yields  gnanidin  on 
decomposition  with  chlorine-water  differentiates  it  from  6-amino-2-oxypurin, 
which  is  considered  as  an  oxidation  product  of  adenin  and  possibly  occurs 
as  a  chemical  metabolic  product  (E.  Fischer).  The  6-amino-2-oxypurin 
sulphate  contains  only  1  mol.  water  of  crystallization,  which  is  not  expelled 
at  120°  C.  Very  dilute  guanin  solutions  are  precipitated  by  both  picric 
acid  and  metaphosphoric  acid.  These  precipitates  may  be  used  in  the 
quantitative  estimation  of  guanin.  The  silver  combination  dissolves  with 
difficulty  in  boiling  nitric  acid,  and  on  cooling  the  double  combination 
crystallizes  out  readily.  Guanin  acts  like  xanthin  in  the  nitric-acid  test, 
but  gives  with  alkalies  on  heating  a  more  bluish-violet  color.  A  warm  solu- 
tion of  ^anin  hydrochloride  gives  with  a  cold  saturated  solution  of  picric 
acid  a  yellow  precipitate  consisting  of  silky  needles  (Capranica).  .  With  a 
concentrated  solution  of  potassium  bichromate  a  guanin  solution  gives  a 
crystalline,  orange-red  precipitate,  and  with  a  concentrated  solution  of 
potassium  ferricyanide  a  yellowish-brown,  crystalline  precipitate  (Capra- 
jstica).  The  composition  of  these  and  other  guanin  combinations  has  been 
studied  by  Kossel  and  Wulff,'     Guanin  does  not  give  Weidel's  reaction. 

HN— CO 

I       I 
Hypoxanthin  or  Sarkin,  C5H4N4O  =  HC     C— NH 

J|_C_N^CH  =  6-oxypurin. 

This  body  is  found  in  the  same  tissues  as  xanthin.  It  is  especially  abun- 
dant in  the  sperm  of  the  salmon  and  carp.  Hypoxanthin  occurs  also  in  the 
marrow  and  in  very  small  quantities  in  normal  urine,  and,  as  it  seems,  also 
in  milk.  It  is  found  in  rather  considerable  quantities  in  the  blood  and 
urine  in  leucaemia. 

Hypoxanthin  forms  very  small  colorless  crystalline  needles.  It  dissolves 
with  difficulty  in  cold  water,  but  the  statements  in  regard  to  the  solubility 
therein  are  very  contradictory.*     It  dissolves  more  readily  in  boiling  water, 

'  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  17. 

'  Ueber  die  chem.  Zusammensetz  der  Zelle,  Verb.  d.  physiol.  Gesellsch.  zu  Berlin, 
1890-91.  No3.  5  and  6. 

2  Zeitscbr.  f.  pbysiol.  Chem..  Bd.  17  ;  Capranica.  ibid.,  Bd.  4. 
*  See  E.  Fischer,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  30. 


HTPOXANTniN  AND  ADENIN.  119 

in  about  70-80  parts.  It  is  nearly  insoluble  in  alcohol,  but  is  dissolved  by- 
acids  and  alkalies.  The  combination  with  hydrochloric  acid  is  crystalline, 
but  is  more  soluble  than  the  corresponding  xanthin  combination.  This 
combination  is  easily  soluble  in  dilute  alkalies  and  ammonia.  The  silver 
combination  dissolves  with  difficulty  in  boiling  nitric  acid.  On  cooling  a 
mixture  of  two  hypoxanthiu  silver-nitrate  combinations  not  having  a  con- 
stant composition  separates  out.  On  treating  this  mixture  with  ammonia 
and  excess  of  silver  nitrate  in  the  warmth,  a  hypoxanthin  silver  combination 
is  formed  which  when  dried  at  120°  C.  has  a  constant  composition, 
2(C\H,Ag,N^O)irjO,  and  which  is  used  in  the  quantitative  estimation  of 
hypoxanthin.  Hypoxanthin  picrate  is  soluble  with  difficulty,  but  if  a 
boiling-hot  solution  of  the  same  is  treated  with  a  neutral  or  only  faintly 
acid  solution  of  silver  nitrate  the  hypoxanthin  is  nearly  quantitatively  pre- 
cipitated as  the  compound  CjH,AgN^0.C,n,(N0j30H.  Hypoxanthin 
does  not  yield  an  insoluble  compound  with  metaphosphoric  acid.  "When 
treated,  like  xanthin,  with  nitric  acid  it  yields  a  nearly  colorless  residue 
which  on  warming  with  alkali  does  not  turn  red.  Hypoxanthin  does  not 
give  AYeidel's  reaction.  After  the  action  of  hydrochloric  acid  and  zinc  a 
hypoxanthin  solution  becomes  first  ruby-red  and  then  brownish  red  in  color 
on  the  addition  of  an  excess  of  alkali  (Kossel).  According  to  E.  Fischer  ' 
a  red  coloration  occurs  even  in  the  acid  solution. 
•  N  =  C.NH, 

Adenin,  CJI.N.  =  lie     (!— NHv 

II      II  ^CH  =  6-aminopurin  was  first  found 

^=(—  X  ^ 
by   Kossel'    in    the   pancreas.     It   occurs  in  all  nucleated  cells,  but   in 
greatest  quantities  in  the  sperm  of  the  carp  and  in  the  thymus.     Adenin 
has  also  been  found  in  lencwmic  urine  (Stadthagen  ').    It  may  be  obtained 
in  large  quantities  from  tea-leaves. 

Adenin  crystallizes  with  3  mol.  water  of  crystallization  in  long  needles 
which  become  opaque  gradually  in  the  air,  but  much  more  rapidly  when 
warmed.  If  the  crystals  are  warmed  slowly  with  a  quantity  of  water 
insufficient  for  solution,  they  become  suddenly  cloudy  at  53°  C,  a  charac- 
teristic reaction  for  adenin.  It  dissolves  in  1086  parts  cold  water,  but  is 
easily  soluble  in  warm.  It  is  insoluble  in  ether,  but  somewhat  soluble  in 
hot  alcohol.  Adenin  is  easily  soluble  in  acids  and  alkalies.  It  is  more  easily 
soluble  in  ammonia  solution  than  guanin,  but  less  soluble  than  hypoxanthin. 
The  silver  combination  of  adenin  is  difficultly  soluble  in  warm  nitric  acid, 
and  deposits  on  cooling  as  a  crystalline  mixture  of  adenin  silver  nitrates. 

>  Kossel,  Zeitschr.  f.  physiol.  Cbein.,  Bd.  12,  S.  252;  E.  Fischer,  1.  c. 
'  See  Zeitschr.  f.  physiol.  Chem.,  Bdd.  10  aud  12. 
»  Virchow's  Arch.,  Bd.  109. 


120  THE  ANIMAL   CELL. 

With  picric  acid  adenin  forms  a  compound,  CJIj]Srj.C,H3(NOj30H,  which 
is  very  insoluble  and  which  separates  more  readily  than  the  hyjDOxanthin 
picrate  and  which  can  be  used  in  the  quantitative  estimation  of  adenin. 
We  also  have  an  adenin  mercury  jDicrate.  Adenin  gives  a  precij^itate  which 
dissolves  in  an  excess  of  the  acid,  with  metaphosphoric  acid,  if  the  solution 
is  not  too  dilute.  Adenin  hydrochloride  gives  with  gold  chloride  a  double 
combination  which  consists  in  part  of  leaf-shaped  aggregations  and  in  part 
of  cubical  or  prismatic  crystals,  often  with  rounded  corners.  This  com- 
pound is  used  in  the  microscopic  detection  of  adenin.  With  the  nitric-acid 
test  and  with  Weidel's  reaction  adenin  acts  in  the  same  way  as  hypoxan- 
thin.  The  same  is  true  for  its  behavior  to  hydrochloric  acid  and  zinc  and 
subsequent  addition  of  alkali. 

The  principle  for  the  preparation  and  detection  of  the  four  above- 
described  xanthin  bodies  in  organs  and  tissues  is,  according  to  Kossel  and 
his  pupils,  as  follows:  The  finely  divided  organ  or  tissue  is  boiled  for  three 
or  four  hours  with  sulphuric  acid  of  about  5  p.  m.  The  filtered  liquid  is 
freed  from  proteid  by  basic  lead  acetate,  and  the  new  filtrate  is  treated  with 
sulphuretted  hydrogen  to  remove  the  lead,  again  filtered,  concentrated, 
and,  after /adding  an  excess  of  ammonia,  precipitated  with  ammoniacal 
silver  nitrate.  The  silver  combination  (with  the  addition  of  some  urea  to 
prevent  nitrification)  is  dissolved  in  not  too  large  a  quantity  of  boiling  nitric 
acid  of  sp.  gr.  1.1,  and  this  solution  filtered  boiling  hot.  On  cooling  the 
xanthin  silver  remains  in  the  solution,  while  the  double  combination  of 
guaniu,  hypoxanthin,  and  adenin  crystallizes  out.  The  xanthin  silver  may 
be  precipitated  from  the  filtrate  by  the  addition  of  ammonia,  and  the 
xanthin  set  free  by  means  of  sulphuretted  hydrogen.  The  three  above- 
mentioned  silver  nitrate  combinations  are  decomposed  in  water  with 
ammonium  sulphide  and  heat;  the  silver  sulphide  is  filtered,  the  filtrate 
concentrated,  saturated  with  ammonia,  and  digested  on  the  water-bath. 
The  guanin  remains  undissolved,  while  the  other  two  bases  pass  into  solu- 
tion. A  part  of  the  guanin  is  still  retained  by  the  silver  sulphide,  and  may 
be  liberated  by  boiling  it  with  dilute  hydrochloric  acid  and  then  saturating 
the  filtrate  with  amniotiia.  When  the  above  filtrate,  containing  the  adenin 
and  hypoxanthin,  which  has  been,  if  necessary,  freed  from  ammonia  by 
evaporation,  is  allowed  to  cool,  the  adenin  separates,  while  the  hypoxanthin 
remains  in  solution.  According  to  Balke  '  we  can  to  advantage  precipitate 
the  xanthin  bases  with  copper  salt  and  hydroxylamin  as  above  mentioned 
and  then  farther  separate  the  bodies. 

The  prominent  points  in  the  above  method  are  made  use  of  in  the  quan- 
titative estimation  of  xanthin  bodies.  The  xanthin  is  weighed  as  xanthin 
silver.  The  three  silver  nitrate  combinations  are  transformed  into  the 
corresponding  silver  combination  by  the  addition  of  ammonia  with  silver 
nitrate  and  then  this  acted  on,  after  thorough  washing,  by  ammonium 
sulphide.  Guanin  is  weighed  as  such,  Tiie  ammoniacal  filtrate  containing 
the  adenin  and  hypoxanthin,  and  which  must  not  be  mixed  with  the  hydro- 
chloric-acid extract  of  the  silver  sulphide,  is  neutralized  and  treated  with  a 

»1.  c. 


PItEPARATlON  OF  NUCLEIN  BASES.  121 

cold  concentrated  solntion  of  sodium  picrate  until  the  solution  is  pro- 
nouncedly yellow.  The  adenin  j)icrate  is  filtered  oil  immediately,  washed 
on  the  filter  with  water,  dried  at  above  100°  C,  and  weighed.  The  filtrate 
containing  the  hypoxanthin  is  gradually  treated,  while  boiling  hot,  with 
silver  nitrate,  and  when  cold  treated  with  silver  nitrate  to  see  whether 
precipitation  has  been  complete.  The  hypoxanthin  picrate  is  washed,  dried 
at  100°  C,  and  weighed.  In  regard  to  the  composition  of  these  compounds 
see  pages  111*  and  I'^O.  This  method  of  separating  adenin  and  hypoxanthin 
presupposes  that  the  liquid  does  not  contain  any  hydrocldoric  acid. 

The  above  method  of  separation  with  ammonia  does  not  give  exact 
results  on  account  of  the  not  inconsiderable  solubility  of  guanin  in  warm 
ammonia.  According  to  Kosski.  and  Wulff  '  the  guanin  may  therefore  be 
precipitated  from  sufficiently  dilate  solutions  by  an  excess  of  metaphos- 
phoric  acid  and  the  nitrogen  determined  in  the  washed  precipitate  by 
K.teldaiil's  method.  The  adenin  and  hypoxanthin  may  be  precipitated 
from  the  filtrate  by  ammoniacal  silver  nitrate.  The  silver  compound  is 
decomposed  with  very  dilute  hydrochloric  acid  and  the  adenin  sejiarated 
from  tlie  hypoxanthin  according  to  the  suggestion  of  Bruiixs.' 

Mineral  bodies  are  never-failing  constituents  of  the  cell.  These  mineral 
bodies  are  potassium,  sodium,  calcium,  magnesium,  iron,  phosphoric  acid, 
and  chlorine.  In  regard  to  the  alkalies  Ave  find  in  general  in  the  animal 
organism  that  the  sodium  combinations  are  more  abundant  in  the  fluids, 
and  the  potassium  combinations  in  the  form-constituents  and  in  the  proto- 
plasm. Corresponding  to  this  the  cell  contains  potassium,  chiefly  as  phos- 
phate, while  the  sodium  and  chlorine  combinations  occur  less  abundantly. 
According  to  the  ordinary  views  the  potassium  combinations,  especially  the 
potassium  phosphate,  are  of  the  greatest  importance  for  the  life  and 
development  of  the  cell,  even  though  we  do  not  know  the  nature  of  the 
importance. 

In  regard  to  the  phosphoric  acid  there  seems  to  be  no  doubt  that  its 
importance  lies  chiefly  in  that  it  takes  part  in  the  formation  of  lecithins  and 
nucleins  and  thereby  indirectly  makes  possible  the  processes  of  growth  and 
division,  which  are  dependent  upon  the  cell  nucleus.  Loew'  has  shown, 
by  means  of  cultivation  experiments  on  algae  Spirogyra,  that  only  on  the 
supplying  of  phosphate  (in  his  experiments  potassium  phosphate)  was  the 
nutrition  of  the  cell  nucleus  made  possible,  and  thereby  the  growth  and 
division  of  the  cells.  The  cells  of  the  Spirogyra  can  be  kept  alive  and 
indeed  produce  starch  and  j^roteids  for  some  time  without  a  supply  of 
phosphates,  but  its  growth  and  propagation  suffer. 

Iron  seems  to  occur  especially  in  the  nucleus,  because  the  nucleins  are 
very  rich  therein.  The  regular  occurrence  of  earth}'  phosphates  in  all  cells 
and  tissues,  as  also  the  difficulty  or  rather  the  imjiossibility  of  separating 

'  Zeitschr.  f.  pliysiol.  Cbem.,  Bd.  17. 

»  Ibid.,  Bil.  14   S.   559. 

«  Biologiscbes  Ceiitnilbl.,  Bd.  11.  1891.  S.  269. 


122  •  THE  ANIMAL   CELL. 

these  bodies  from  the  protein  bodies  without  modifying  them,  leads  to  the 
sujjpositiou  that  these  mineral  bodies  are  of  unknown  but  nevertheless  great 
importance  for  the  life  of  the  cell,  as  well  as  the  chemical  processes  going 
on  within  them.  The  necessity  of  lime  salts  for  plants,  with  the  exception 
of  certain  lower  forms,  has  been  shown  by  tlie  investigations  of  Loew  ' 
and  others. 

*  See  Botanisches  Centralbl.,  Bd.  74. 


CHAPTER   VI. 

THE   BLOOD. 

The  blood  is  to  be  considered  from  a  certain  standpoint  as  a  fluid  tissue, 
and  it  consists  of  a  transjjarent  liquid,  the  blood-plasma,  in  which  a  vast 
number  of  solid  particles,  the  red  and  white  blood-corjmscles  (and  the  blood- 
plates)  are  suspended.  We  also  find  in  blood  grannies  of  different  kinds, 
which  are  to  be  considered  as  transformation  products  of  the  form-elements.' 

Outside  of  the  organism  the  blood,  as  is  well  known,  coagulates  more  or 
less  quickly;  but  this  coagulation  is  accomplished  generally  in  a  few  minutes 
after  leaving  the  body.  All  varieties  of  blood  do  not  coagulate  with  the 
same  degree  of  rapidity.  Some  coagulate  more  quickly,  others  more  slowly. 
In  vertebrates  with  nucleated  blood  corpuscles  (birds,  reptiles,  batrachia, 
and  fishes)  Delezennp:^  has  shown  that  the  blood  coagulates  very  slowly, 
if  it  is  collected  under  precautions  so  that  it  does  not  come  in  contact  with 
the  tissues.  On  contact  with  the  tissues  or  with  the  tissue  extract  they 
coagulate  in  a  few  minutes.  The  blood  of  non-nucleated  blood-corpuscles 
(mammals)  coagulates,  on  the  contrary,  very  rapidly.  Among  the  varieties 
of  blood  of  mammals  thus  far  investigated  the  blood  of  the  horse  coagulates 
most  slowly.  The  coagulation  may  be  more  or  less  retarded  by  quickly 
cooling;  and  if  we  allow  equine  blood  to  flow  directly  from  the  vein  into  a 
glass  cylinder  which  is  not  too  wide  and  which  has  been  cooled,  and  let  it 
stand  at  0"  C,  the  blood  may  be  kept  fluid  for  several  days.  An  upper, 
amber-yellow  layer  of  plasma  gradually  separates  from  a  lower,  red  layer 
composed  of  blood-corpuscles  with  only  a  little  plasma.  Between  these  we 
observe  a  whitish-gray  layer,  Avhich  consists  of  white  blood-corpuscles. 

The  plasma  thus  obtained  and  filtered  is  a  clear  amber-yellow  alkaline 
liquid  which  remains  fluid  for  some  time  when  kept  at  0°  C,  but  soon 
coagulates  at  the  ordinary  temperature. 

The  coagulation  of  the  blood  may  be  prevented  in  other  ways.  After 
the  injection  of  peptone  or,  more  correctly,  albumose  solutions  into  the 
blood  (in  the  living  dog),  the  blood  does  not  coagulate  on  leaving  the  veins 
(Fano,  Schmidt-Mulheim ').     The  plasma  obtained  from  such  blood  by 

'  See  Latscbenberger,  Wien.  Sitzungsber.,  Bd.  105. 

*  Coinpt.  reud.  Soc.  de  Biol.,  Tome  49. 

»  Fauo,  Du  Bois-Reymond's  Arch.,  1881;  Schmidt-Mulheim,  ibid.,  1880. 

123 


124  TEE  BLOOD. 

means  of  centrifugal  force  is  called  ^^ jje^jtone-plasma.''^  According  to 
Arthus  and  Huber  '  the  caseoses  and  gelatoses  act  similar  to  fibrin  albn- 
moses  in  dogs.  The  coagulation  of  the  blood  of  warm-blooded  animals  is 
prevented  by  the  injection  of  an  effusion  of  the  mouth  of  the  officinal  leech 
into  the  blood-current  (Haycraft*).  If  we  allow  the  blood  to  flow 
directly,  while  we  stir  it,  into  a  neutral  salt  solution — best  a  saturated 
magnesium-sulphate  solution  (1  vol.  salt  solution  and  3  vols,  blood) — we 
obtain  a  mixture  of  blood  and  salt  which  remains  uncoagulated  for  several 
days.  The  blood-corpuscles  which,  because  of  their  adhesiveness  and 
elasticity,  would  otherwise  pass  easily  through  the  pores  of  the  filter-paper 
are  made  solid  and  stiff  by  the  salt,  so  that  they  may  be  easily  filtered. 
The  plasma  thus  obtained,  which  does  not  coagulate  spontaneously,  is  called 
' '  salt-plasma. ' ' 

An  especially  good  method  of  presenting  coagulation  of  blood  consists 
in  drawing  the  blood  into  a  dilute  solution  of  potassium  oxalate,  so  that  the 
mixture  contains  O.lfo  oxalate  (Arthus  and  Pages  ').  The  soluble  calcium 
salts  of  the  blood  are  precipitated  by  the  oxalate,  and  hence  the  blood  loses 
its  coagulability.  On  the  other  hand  Horxe''  found  that  chlorides  of 
calcium/Darium,  and  strontium,  when  present  in  large  amounts  (2-3^)  may 
prevent  coagulation  for  several  daj^s. 

On  coagulation  there  separates  in  the  previously  fluid  blood  an  insoluble 
or  a  very  difficultly  soluble  albuminous  substance,  ^^n'^i.  When  this  sepa- 
ration takes  place  without  stirring,  the  blood  coagulates  to  a  solid  mass 
which,  Avhen  carefully  severed  from  the  sides  of  the  vessel,  contracts,  and  a 
clear,  generally  yellow-colored  liquid,  the  blood-serum,  exudes.  The  solid 
coagulum  which  encloses  the  blood-corpuscles  is  called  the  blood-clot 
(placenta  sanguinis).  If  the  blood  is  beaten  during  coagulation,  the  fibrin 
separates  in  elastic  threads  or  fibrous  masses,  and  the  defihrinated  blood 
which  separates  is  sometimes  called  crnor,"  and  consists  of  blood-corpuscles 
and  blood-serum.  Defihrinated  blood  consists  of  blood-corpuscles  and 
serum,  while  uncoagulated  blood  consists  of  blood -corpuscles  and  blood- 
plasma.  The  essential  chemical  difference  between  blood-serum  and  blood- 
plasma  is  that  the  blood-serum  does  not  contain  evea  traces  of  the 
mother-substance  of  fibrin,  the  fibrinogen,  which  exists  in  the  blood-plasma, 


'  Arch,  de  physiol.  (■">),  8. 

»  Proc.  physiol.  Soc.  1884,  p.  13,  and  Arch.  f.  exp.  Path.  u.  Pharm.  18. 

3  Archives  de  Physiol    (5),  2  and  Compt.  rend,  112. 

*  Journ.  of  Physiol.,  Vol.  19. 

*  The  name  cruor  is  used  in  different  senses.  We  sometimes  understand  thereby 
only  the  blood  when  coagulated  to  a  red  .«olid  mass,  in  other  cases  the  blood-clot  after 
the  separation  of  the  serum,  and  lastly  the  sediment  consisting  of  red  blood-corpuscles 
which  is  obtained  from  defihrinated  blood  by  means  of  centrifugal  force  or  by  letting  it 
Btand. 


BLOOD-PLASMA.  125 

and  the  sernm  is  proportionally  richer  in  another  body,  the  fibrin  ferment 
(see  page  137). 

t,  BUxxl-plasiiia  and  Bloocl-seruiii. 

The  Blood-plasma. 

In  the  coagulation  of  the  blood  a  chemical  transformation  takes  place  in 
the  plasma.  A  part  of  tlie  ])roteids  separates  as  insoluble  fibrin.  The 
albuminous  bodies  of  the  plasma  must  therefore  be  first  described.  They 
are,  as  far  as  we  known  at  present,  fihriyiogen,  serglohulin,  and  seralbumin. 

Fibrinogen  occurs  in  blood-plasma,  chyle,  lymph,  and  in  certain  transu- 
dations and  exudations.'  It  has  the  general  properties  of  the  globulins,  but 
differs  from  other  globulins  as  follows:  In  a  moist  condition  it  forms  white 
flakes  which  are  soluble  in  dilute  common-salt  solutions,  and  which  easily 
conglomerate  into  tough,  elastic  masses  or  lumps.  The  solution  in  XaCl 
of  5-10,^  coagulates  on  heating  to  +  52-55"  C,  and  the  faintly  alkaline 
or  nearly  neutral  weak  salt  solution  coagulates  at  -|-  50°  C,  or  at  exactly 
the  same  temperature  at  which  the  blood-plasma  coagulates.  Fibrinogen 
solutions  are  precipitated  by  an  equal  volume  of  a  saturated  common-salt 
solution,  and  are  completely  precipitated  by  adding  an  excess  of  XaCl  in 
substance  (thus  differing  from  serglobulin).  A  salt-free  solution  of 
fibrinogen  in  as  little  alkali  as  possible  gives  with  CaCl,,  a  precipitate  con- 
taining calcium  and  soon  becoming  insoluble.  In  the  presence  of  XaCl  or 
by  the  addition  of  an  excess  of  CaCl,  the  precipitate  does  not  appear.'^  It 
differs  from  myosin  of  the  muscles,  which  coagulates  at  about  the  same 
temjierature,  and  from  other  albuminous  bodies,  in  the  projierty  of  being 
converted  into  fibrin  under  certain  conditions.  Fibrinogen  has  a  strong 
decomposing  action  on  hydrogen  peroxide.  It  is  quickly  made  insoluble  by 
precipitation  with  water  or  with  dilute  acids.'  Its  specific  rotation  is 
nf(r))  =  —  52.5°  according  to  ^Iittelbacii.* 

Fibrinogen  may  be  easily  separated  from  the  salt-plasma  or  oxalate 
plasma  by  precipitation  with  an  equal  volume  of  a  saturated  XaCl  solution. 
For  further  purification  the  precipitate  is  pressed,  redissolved  in  an  8;^  salt 
solution,  the  filtrate  precipitated  by  a  saturated-salt  solution  as  above,  and 
after  precii)itating  in  this  way  three  times,  the  precipitate  at  last  obtained 
is  pressed  between  filter-paper  and  finely  divided  in  water,  Tiie  fibrinogen 
dissolves  with  the  aid  of  the  small  amount  of  XaCl  contained  in  itself,  and 

'  The  (luestiou  us  to  the  occurrence  of  other  fibriuogens  (Woolduidge)  will  be 
spokeu  of  in  conneclioa  with  the  complete  discussion  of  the  coagulation  of  tlie  blood. 
(See  further  on.) 

"  See  Hamraarsten,  Zeitschr.  f.  physiol.  Chem.,  Bd.  23;  Cramer,  ibid.,  Bd.  23. 

'  In  regard  to  fibrinogen  the  reader  is  referred  to  the  author's  investigations.  Pflii- 
ger's  Archiv.,  Bdd.  19  and  23. 

■*  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 


126  THE  BLOOD. 

the  solntion  may  be  made  salt-free  by  dialysis  with  very  faintly  alkaline 
water.  Fibrinogen  may  also,  according  to  Eete/  be  prepared  by  frac- 
tionally jarecipitating  the  plasma  with  a  saturated  solntion  of  ammonium 
sulphate.  We  have  no  investigatious  as  regards  the  purity  of  the  fibrinogen 
so  prepared.  From  transudations  we  ordinarily  obtain  a  fibrinogen  which 
is  strongly  contaminated  with  lecithin  and  which  can  hardly  be  purified 
without  decomposing.  The  methods  for  the  detection  and  quantitative 
estimation  of  fibrinogen  in  a  liquid  used  to  be  based  on  its  property  of 
yielding  fibrin  on  the  addition  of  a  little  blood,  of  serum,  or  of  fibrin 
ferment.  Eeye  has  suggested  the  fractional  precipitation  with  ammonium 
sulphate  as  a  quantitative  method.  The  value  of  this  method  has  not  been 
sufficiently  tested. 

The  fibrinogen  stands  in  close  relation  to  its  transformation-product,  the 
fibrin. 

Fibrin  is  the  name  of  that  proteid  body  which  separates  on  the  so-called 
spontaneous  coagulation  of  blood,  lymph,  and  transudation,  as  also  in  the 
coagulation  of  a  fibrinogen  solntion  after  the  addition  of  serum  or  fibrin 
ferment  (see  below). 

If  thje  blood  is  beaten  during  coagulation,  the  fibrin  separates  in  elastic, 
fibrous  masses.  The  fibrin  of  the  blood-clot  may  be  beaten  to  small,  less 
elastic,  and  not  particularly  fibrous  lumps.  The  typical,  fibrous,  and  elastic 
white  fibrin,  after  washing,  stands  in  regard  to  its  solubility  close  to  the 
coagulated  proteids.  It  is  insoluble  in  water,  alcohol,  or  ether.  It  expands 
in  hydrochloric  acid  of  1  j).  m.,  as  also  in  caustic  potash  or  soda  of  1  p.  m., 
to  a  gelatinous  mass,  which  dissolves  at  the  ordinary  temjDerature  only  after 
several  days,  but  at  the  temperature  of  the  body  it  dissolves  more  readily 
but  still  slowly.  Fibrin  may  be  dissolved  by  dilute  salt  solutions  after  a 
long  time  at  the  ordinary  temperature  or  much  more  readily  at  40°  C,  and 
this  solntion  takes  i:)lace,  according  to  Arthus  and  Huber  and  also 
Dastre,''  without  the  aid  of  micro-organisms.  According  to  Greei^  and 
Dastre  '  two  globulins  are  formed  in  this  solution  of  fibrin.  Fibrin  decom- 
poses hydrogen  peroxide,  but  this  property  is  destroyed  by  heating  or  by  the 
action  of  alcohol. 

What  has  been  said  of  the  solubility  of  fibrin  relates  only  to  the  typical 
fibrin  obtained  from  the  arterial  blood  of  mammals  or  man  by  wliipping  and 
washing  first  with  water  and  with  common-salt  solution,  and  then  with 
water  again.  The  blood  of  various  kinds  of  animals  yields  fibrin  with 
somewhat  different  properties,  and  according  to  Fermi*  jiig-fibrin  dissolves 
much  more  readily  in  hydrochloric  acid  of  5  p.  m.  than  ox-fibrin.     Fibrins 

'  W,  Reye,  Ueber  Nachweis  und  BestimmuDg  des  Fibrinogens,  Inaug.-Diss.,  Slrass- 
burg.  1898. 

'  Arlbur  and  Huber,  Arcli.  do  pbysiol.  (5),  Tome  5 ;  Dastre,  ibid.  (5),  Tome  7. 
^  Green,  .Jouni.  of  Pbysiol.  Vol.  8;  Dastre,  1.  c. 
*  Zeitscbr.  f.  Biologic,  Bd.  28. 


FIBRIN.  127 

of  varying  purity  or  originating  from  blood  from  different  parts  of  the  body 
•have  unlike  solnbilities. 

The  fibrin  obtained  by  beating  the  blood  and  purified  as  above  described 
is  always  contaniiiuited  by  enclosed  blood-corpuscles  or  remains  thereof,  and 
also  by  lymphoid  cells.  It  can  only  be  obtained  pure  from  filtered  plasma 
or  filtered  transudations.  For  the  pure  preparation,  as  well  as  for  the 
quantitative  estimation  of  fibrin,  the  spontaneously  coagulating  lifjuid  is  at 
once,  or  the  non-spontaneously  coagulating  liquid  only  after  the  addition  of 
blood -serum  or  fibrin  ferment,  thoroughly  beaten  with  a  whalebone,  and 
the  separated  coagulum  is  washed  first  in  water,  and  then  with  a  b% 
common-salt  solution,  and  again  with  water,  and  lastly  extracted  with 
alcohol  and  ether.  If  the  fibrin  is  allowed  to  stand  in  contact  with  the 
blood  from  which  it  was  formed  for  some  time,  it  partly  dissolves 
(fibrinolysis — Dastre  ').  This  fibrinolysis  must  be  prevented  in  the  exact 
quantitative  estimation  of  fibrin  (Dastrj;). 

A  pure  fibrinogen  solution  may  be  kept  at  the  ordinary  temperature 
until  putrefaction  begins  without  showing  a  trace  of  fibrin  coagulation. 
But  if  to  this  solution  we  add  a  water-washed  fibrin-clot  or  a  little  blood- 
Bernm,  it  immediately  coagulates  and  may  yield  perfectly  tyjiical  fibrin. 
The  transformation  of  the  fibrinogen  into  fibrin  requires  the  presence  of 
another  body  contained  iu  the  blood-clot  and  in  the  serum.  This  body, 
whose  importance  in  the  coagulation  of  fibrin  was  first  observed  by 
BucHAXAX,'  was  later  rediscovered  by  Alexander  Schmidt'  and  desig- 
nated ^\fibriH-fer7nent^^  or  thrombin.  The  nature  of  this  enzymotic  body 
has  not  been  ascertained.  Although  many  investigators,  especially  English, 
consider  fibrin-ferment  as  a  globulin,  still  more  recent  experiments  of 
Pekelharing/  and  others  show  that  it  is  a  uucleoproteid.  Fibrin  ferment 
is  produced,  according  to  Pekelharing,  by  the  influence  of  soluble 
calcium  salts  on  a  preformed  zymogen  existing  in  the  non-coagulated 
plasma.  Schmidt  admits  of  the  presence  of  such  a  mother-substance  of  the 
fibrin  ferment  in  the  blood  and  ca\\%  it  j^rothromhin.  The  prothrombin  as 
well  as  the  thrombin  is  less  soluble  in  an  excess  of  acetic  acid  than  the 
globulins,  and  yields  a  nuclein  or  a  pseudonuclein  on  peptic  digestion. 
Thrombin  corresponds  to  other  enzymes  in  that  the  very  smallest  amount 
of  it  produces  an  action  and  its  solution  becomes  inactive  on  heating.  It  is 
most  active  at  about  40"  C.     Prothrombin,  according  to  Pekeliiarixg,  is 

*  Archives  de  Physiol.  (5),  Tomes  .'i  and  6. 

*  Loudon  Med.  O.izette,  1845,  p.  617.     Cit.  by  Gamgec,  Journal  of  Physiol.,  1879. 

'  Pfliiiier's  Archiv,  Bd.  6  ;  also  zur  Blutlehre,  1892,  and  Weitere  Beitriige  zur  Blut- 
lehre,  189J. 

■•  Pekelh.'iriufr,  Vcrhandel.  d.  kon.  Akad.  d.  Wetcnsch.  te  Amsterdam,  1892,  Deel  1  ; 
ibid.,  189o,  and  Centralbl.  f.  physiol.,  Bd.  9;  Wright,  Proc.  Koy.  Irish  Acad.  (3), 
Vol.  2,  The  Lancet,  181)2,  and  On  Wooldridge's  Method,  etc.,  British  Med.  Journal,  1891, 
Lilienfeld,  Haematol.  Untersuch.,  Du  Bois-Rcymond's  Arch.,  1892;  L'eber  Leukocyten 
und  Blutgeriunung,  ibid.  ;  Halliburton  and  Brodie,  Journal  of  Physiol.,  Vols.  17,  18. 


128  THE  BLOOD. 

destroyed  at  abont  -|-  65°  C,  while  the  thrombin  is  destroyed  at  about  the 
same  or  sometimes  at  a  little  higher  temperature,  70-75°  C. 

The  isolation  of  the  fibrin-ferment  has  been  tried  in  several  ways. 
Ordinarily  it  may  be  prepared  by  the  following  method  projiosed  by  Alex. 
Schmidt.'  Precipitate  the  serum  or  defibrinated  blood  with  15-20  vols,  of 
alcohol  and  allow  it  to  stand  a  few  months.  The  precipitate  is  then  filtered 
and  dried  over  sulphuric  acid.  The  ferment  may  be  extracted  from  the 
dried  powder  by  means  of  water.  Other  methods  have  been  suggested  by 
the  AUTHOE  and  by  Pekelharing.' 

The  preparation  of  a  thrombin  solution,  as  free  as  possible  from  lime, 
may  be  done  by  removing  the  lime  salts  from  the  sernm  by  means  of  oxalate 
and  precipitating  the  serum  with  alcohol  and  allowing  it  to  stand  nnder 
alcohol  for  several  months.  The  dried  powder  is  rubbed  with  water  and 
freed  from  soluble  salts  by  repeated  lixiviation  with  water  and  the  use  of 
centrifugal  force.  Then  allow  each  gramme  of  powder  to  stand  some  time 
with  100-150  c.c.  water,  filter  and  in  this  way  obtain  a  solution  which  con- 
tains only  about  0.3-0.4  p.  m.  solids  and  about  0.0007  p.  m.  CaO.    (Authoe.) 

If  a  fibrinogen  solution  containing  salt,  as  above  prepared,  is  treated 
with  a  solution  of  "  fibrin-ferment,"  it  coagulates  at  the  ordinary  tempera- 
ture more  or  less  quickly  and  yields  a  typical  fibrin.  Besides  the  fibrin- 
ferment  the  presence  of  neutral  salts  is  necessary,  for  without  them  Alex. 
Schmidt  has  shown  the  fibrin  coagulation  does  not  take  place.  The 
presence  of  soluble  calcium  salts  is  not,  as  generally  admitted  with  Arthus, 
a  positive  condition  for  the  formation  of  fibrin,  because  as  shown  by  Alex. 
Schmidt,  Pekelhaeii^g,  and  the  authoe,^  thrombin  can  transform 
fibrinogen  into  typical  fibrin  in  the  absence  of  lime  salts  precipitable  by 
oxalate.  The  quantity  of  fibrin  obtained  on  coagulation  is  always  smaller 
than  the  amount  of  fibrinogen  from  which  the  fibrin  is  derived,  and  we 
always  find  a  small  amount  of  protein  substance  in  the  solution.  It  is 
therefore  not  improbable  that  the  fibrin  coagulation,  in  accordance  with  the 
views  first  proposed  by  Denis,  is  a  cleavage  process  in  which  the  soluble 
fibrinogen  is  split  into  an  insoluble  albuminous  body,  the  fibrin,  which 
forms  the  chief  mass,  and  a  soluble  protein  substance  which  is  only  formed 
in  small  amounts.  We  find  a  globulin-like  substance  which  coagulates  at 
about  -f-  6-J:°  C.  in  blood-serum  as  well  as  in  the  serum  from  coagulated 
fibrinogen  solutions.  This  substance  is  called  fihria-glolnlin  by  the 
AUTHOR.  The  question  whether  this  substance  exists  in  the  fibrinogen 
solution  as  contamination  or  is  formed  as  a  true  cleavage  product  has  not 
been  positively  decided. 

We  have  also  other  views  in  regard  to  the  processes  of  coagulation  in  the 

>  PflUgcr's  Arch.,  Bd.  6. 

*  Hammarsten.  Pfliiger's  Arch.,  Bd.  18,  Pek('lhann<r,  ].  c. 

'  See  Haminar.sten,  Zeitschr.  f.  physiol.  Clicm.,  Bd.  22,  which  also  cites  the  works 
of  Schmidt  and  Pckelharing. 


8ERQL0BULIN.  129 

formation  of  fibrin  whicli  are  even  less  positively  founded.  The  fact  that 
the  soluble  lime  salts  are  not  necessary  for  the  transformation  of  fibrinogen 
into  fibrin  is  not  in  contradiction  to  the  other  fact  that  they  must  be  present 
in  the  coagulation  of  blood  or  plasma.  This  apparent  contradiction  may 
be  explained,  as  shown  later,  by  the  special  condition  of  the  plood-plasma, 
and  we  must  not  overlook  the.  fact  that  the  coagulation  of  the  blood  is  a 
much  more  complicated  process  than  the  coagulation  of  a  fibrinogen  solu- 
tion, inasmuch  as  the  first  involves  other  important  questions,  as,  for 
instance,  the  reason  for  the  blood  remaining  fluid  in  the  body,  the  origin  of 
the  fibrin-ferment,  and  the  importance  of  the  form-elements  in  the  coagu- 
lation, etc.  A  fuller  discussion  of  the  various  hypotheses  and  theories 
concerning  the  coagulation  of  the  blood  must  therefore  be  given  later. 

Serglobulin,  also  called  paraglolulin  (Kuhne),  fihrinoplastic  substance 
(Alkx.  Schmidt),  serum-casei)i  (Paxum '),  occurs  in  the  plasma,  serum, 
lymph,  transudations  and  exudations,  in  the  white  and  red  corpuscles,  and 
probably  in  many  animal  tissues  and  form-elements,  though  in  small  quan- 
tities.    It  is  also  found  in  the  nrine  in  many  diseases. 

Serglobulin  is  without  doubt  not  an  individual  substance,  but  consists 
of  a  mixture  of  two  or  more  protein  bodies  which  cannot  be  completely  and 
positively  sejiarated  from  each  other.  Under  these  circumstances  the 
statements  in  regard  to  the  properties  of  the  serglobulins  is  naturally  some- 
what uncertain.  According  to  our  present  knowledge  it  has  the  following 
properties: 

Serglobulin  has  the  general  jiroperties  of  the  globulins.  In  a  moist  con- 
dition it  forms  a  snow-white  fiaky  mass  neither  tough  nor  elastic.  The 
essential  differences  between  serglobulin  and  fibrinogen  are  the  following: 
Serglobulin  solutions  are  only  incompletely  precipitated  by  adding  NaCl  to 
saturation,  and  not  precipitated  at  all  by  an  equal  volume  of  a  saturated 
common-salt  solution.  The  coagulation  temperature  is,  with  5-10,^  NaCl 
in  solution,  -|-  75°  C.  It  is  completely  precipitated  by  MgSO^  in  substance 
added  to  saturation,  as  also  by  an  equal  volume  of  a  saturated  solution 
of  ammonium  sulphate.  Tlie  specific  rotatory  power,  according  to 
Fkedkkicq,"  for  serglobulin  (from  ox-blood)  solutions  containing  salt  is 
^(D)  =  -  47.8°. 

According  to  K.  Mouxer  serglobulin  yields  a  reducing  substance  on 
boiling  w^ith  a  dilute  acid.  Tlie  question  whether  the  substance  we  have 
heretofore  called  serglobulin  is  a  glycoproteid  or  whether  it  is  a  mixture  of 
globulin  with   a  glycoproteid  has  not  been  positively  decided   up  to  the 

'  Klibue,  Lebrbuch  d.  pbysiol.  Cbem.  Leipzig,  1866-68  ;— Al.  Scbmidt,  Arch,  f, 
Anat.  u.  Physiol.,  1861-62  ;  Puuuni,  Virchow's  Arch.,  BcM.  3  ii.  4. 

'  Bull.  Acad.  Roy.  do  Beig  (2),  50.  In  regard  to  paraglobuliu,  see  Ilammarstcn, 
Pflilger's  Arcli.,  Bdd.  17  u.  18. 


130  THE  BLOOD. 

present   time.     According  to  Zanetti  blood-sernm  contains   a   glyccpro- 

teid.' 

E.  Faust'  has  isolated  a  body,  wliich  he  calls  glutolin,  from  the  mixture  of  globulins 
•which  is  separated  ou  half  satnratine  horse-serum  with  ammonium  sulphate.  He  con- 
siders this  body  as  an  intermediate  step  between  the  glutin  substances  and  the  true  pro- 
teids.  The  connection  between  this  body  and  the  glutin  group  follows  from  the  fact 
that  glycocol  is  found  among  the  cleavage  products  of  this  substance.  It  differs  from 
globulin  in  being  insoluble  in  neutral  sail  solutions  of  any  concentration;  it  dissolves  in 
'dilute  alkali  or  ammonia,  but  is  precipitated  ou  the  addition  of  acid.  The  analyses  have 
given  the  following  results  :  C  51.20  ;  H  7.24  ;  N  17.42  ;  S  0.641  Glutolin  does  not  con- 
tain any  sulphur  which  blackens  lead. 

Serglobnliu  may  be  easily  separated  as  a  fine  floccnlent  precipitate  from 
blood-sertim  by  neutralizing  or  making  faintly  acid  with  acetic  acid  and 
then  dilating  with  10-20  vols,  of  water.  For  ftirther  purification  this 
precipitate  is  dissolved  in  dilate  common-salt  solution,  or  in  water  by  the 
aid  of  the  smallest  possible  amount  of  alkali,  and  then  reprecipitated  by 
diluting  with  water  or  by  the  addition  of  a  little  acetic  acid.  The 
serglobulin  may  also  be  separated  from  the  serum  by  means  of  magnesium 
or  ammonium  sulphate;  in  these  cases  it  is  difficult  to  completely  remove 
the  salt  by  dialysis.  The  serglobulin  from  blood-serum  is  always  contami- 
nated by  lecithin  and  thrombin.  A  serglobulin  free  from  thrombin  may  be 
prepared  from  ferment-free  transudations,  as  sometimes  from  hydrocele 
fluids,'^and  this  shows  that  serglobulin  and  thrombin  are  different  bodies. 
For  the  detection  and  the  quantitative  estimation  of  serglobulin  we  may  use 
the  precipitation  by  magnesium  sulphate  added  to  satti ration  (Hammarsten), 
or  by  an  equal  volume  of  a  saturated  neutral  ammonium  sulphate  solution 
(HoFMEiSTER  and  Kauder  and  Pohl)."  In  the  quantitative  estimation 
tlie  precipitate  is  collected  on  a  weighed  filter,  washed  with  the  salt  solution 
employed,  dried  with  the  filter  at  about  115°  C,  then  washed  with  boiling- 
hot  water,  so  as  to  completely  remove  the  salt,  extracted  with  alcohol  and 
ether,  dried,  weighed  and  burnt  to  determine  the  ash. 

Seralbumin  is  found  in  large  quantities  in  blood-serum,  blood-plasma, 
lymph,  transudations,  and  exudations.  Probably  it  also  occurs  in  other 
animal  liquids  and  tissues.  The  proteids  which  pass  into  the  urine  under 
pathological  conditions  consist  largely  of  seralbumin. 

In  the  dry  state  seralbumin  forms  a  transparent,  gummy,  brittle,  hygro- 
scopic mass,  or  a  white  powder  which  may  be  heated  to  100°  C.  without 
decomposing.  Its  solution  in  water  gives  the  ordinary  reactions  for 
proteids;  the  specific  rotatory  power,  as  Avell  as  the  coagulation  temperature, 
lias  been  found  to  vary,  which  is  due  in  the  first  place  to  the  fact  that 
what  used  to  be  considered  as  seralbumin  was  a  mixture  of  several  albumins. 
Attention  was  first  called  to  this  fact  by  Halliburton,  who  calls  the  three 
seralbumins  coagulating  at  different  temperatures  seriji.  Gurber  has 
also  found  three  different  serins  in  horse-l)lood  serum,  of  which  two  are 

'  Morner,  Centralbl.  f.  Physiol.,  Bd.  7;  Zanttti,  Chem.  Centralbl.,  1898,  S.  624. 
»  Arch.  f.  exp.  Path.  u.  Pliarni.,  Bd.  41. 

'  Hammarsten,  1.  c. ;  Hofmeister,  Kauder,  and  Pohl,  Arch.  f.  ex|).  Path.  u.  Pharm., 
Bd.  30. 


SERALBUMIN.  131 

crystalline  and  the  third  amorphous.  Mkhki,  '  found  that  the  coagulation 
temperature  for  the  crystalline  serin  in  dialy/^ed  salt-free  solution  was 
51-54°  C. ;  it  rose  with  the  quantity  of  salt  present.  The  specific  rotatory 
power  was  «(!>)  =  —  01°.  The  elementary  composition  was  nearly  the 
same  as  that  of  the  mixture  of  albumins  found  by  the  author  in  horse-blood 
serum  (see  page  132).  One  of  the  serins  crystallizes  in  hexagonal  prisnis, 
the  other  in  long  needles.  The  coagulation  of  the  mixture  of  albumins 
from  serum  generally  takes  place  at  70-85°  C,  but  is  esentially  dependent 
upon  the  reaction  and  the  amount  of  salt  present.  The  specific  rotatory 
power  of  this  mixture  is  '^{\^)  =  —  02.0-04.0°.  Up  to  the  present  time 
no  seralbumin  solution  has  been  prepared  free  from  mineral  bodies.  A 
solution  as  free  from  salts  as  possible  does  not  coagulate  either  on  boiling 
or  on  the  addition  of  alcohol.  On  the  addition  of  a  little  common  salt  it 
coagulates  in  both  cases. ^ 

Seralbumin  differs  from  the  albumin  of  the  white  of  tlie  hen's  egg  in 
the  following  particulars:  it  is  more  hevogyrate;  the  precipitate  formed  by 
hydrochloric  acid  easily  dissolves  in  an  excess  of  the  acid;  is  rendered  less 
insoluble  by  alcohol;  and  lastly  it  acts  differently  inside  of  the  organism. 
If  egg-albumin  is  introduced  into  the  blood  circulation  it  passes  into  the 
urine,  while  seralbumin  does  not  in  the  same  animal  of  the  same  family.' 

In  preparing  seralbumin,  first  remove  the  globulins  according  to 
Johansson,  by  saturating  with  magnesium  sulphate  at  about  +  W^  C,  and 
filtering  at  the  same  temperature.  The  cooled  filtrate  is  separated  from  the 
crystallized  salt  and  is  treated  with  acetic  acid  so  that  it  contains  about  1^.. 
The  precipitate  formed  is  filtered,  pressed,  dissolved  in  water  with  the' 
addition  of  alkali  to  neutral  reaction,  and  the  solution  freed  from  salt  by 
dialysis.  The  mixture  of  albumins  may  be  obtained  in  a  solid  form  from 
the  dialyzed  solution  by  either  evaporating  the  solution  at  a  gentle  tempera- 
ture or  by  precipitating  with  alcohol,  which  must  be  quickly  removed. 
Starke*  lias  suggested  another  method,  which  is  also  to  be  recommended. 
Tiie  crystalline  seralbumin  may  be  prepared  from  serum,  freed  from  globulin 
by  half  saturating  with  ammonium  sulphate,  by  the  addition  of  more  salt 
until  a  cloudiness  occurs  and  then  proceeding  according  to  the  suggestion 
of  OuKBER  and  Michel.  By  acidification  with  acetic  acid  the  crystalliza- 
tion may  be  considerably  enhanced  (Hopkins  and  Pinkus").     According 


'  HnUihurton,  .Jourii.  of  Physiol.,  Vols.  5  and  6;  Giirber,  Sitzungsber.  d.  pbys.- 
med.  Gesellsch.  zu  Wlirzburg,  1894;  A.  Michel,  Verhandl.  d.  pbys.-med.  Gesellsch.  zu 
Wurzburg,  Bd.  29,  No.  3. 

*  lu  regard  to  the  relationship  of  neutral  salts  to  heat  coagulation,  see  J.  Starke, 
Sitzungsber.  d.  Gesellsch.  f.  Morpb.  u.  Physiol,  in  Muncheii,  1897. 

*  See  O.  "Weiss.  Pfluger's  Arch.,  Bdd.  65  u.  68. 

*  Johaussou,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  9  ;  K.  Starke,  Maly's  Jahresber., 
Bd.  11. 

*  Journ.  of  Physiol.,  Vol.  23. 


132  THE  BLOOD. 

to  Krieger  '  crystalline  seralbumin  may  be  obtained  from  horse-serum, 
-which  has  been  freed  from  globulins  by  ammonium  sulphate,  by  the  addi- 
tion of  dilute  sulphuric  acid  (|  normal)  until  a  slight  opalescence  occurs. 
In  the  detection  and  quantitative  estimation  of  seralbumin,  the  filtrate  from 
the  globulins  which  have  been  removed  by  magnesium  sulphate  is  heated  to 
boiling,  after  the  addition  of  a  little  acetic  acid  if  necessary.  The  simplest 
way  is  to  consider  the  difference  between  the  total  proteids  and  the 
globulins  as  seralbumin. 

Summary  of  the  elementary  composition  of  the  above  mentioned  and  described  albu- 
minous bodies: 

C  H  N            S             O 

Fibrinogen     52.93  6.90  16.66  1.25        22.26  (Hammarsten) 

Fibrin       52.68  6.83  16.91  1.10        22.48 

Fibrin-globulin 52.70  6.98  16.06  

Serglobulin 52.71  7.01  15.85  1.11        23.32 

SerSlbumin  (1) 53.06  6.85  16.04  1.80        22.25 

Seralbumin  (2) 52.25  6.65  15.88  2.25        22.97 

The  seralbumin  (2)  came  from  a  human  exudation,  and  the  other  bodies  from  horse's 
blood.     The  fibrin  was  prepared  from  a  filtered  common-salt  plasma. 

/  The  Blood-serum. 

As  above  stated,  the  blood-serum  is  the  clear  liquid  which  is  pressed  out 
by  the  contraction  of  the  blood-clot.  It  differs  chiefly  from  the  plasma  in 
the  absence  of  fibrinogen  and  an  abundance  of  fibrin-ferment.  Considered 
qualitatively  the  blood-serum  contains  the  same  chief  constituents  as  the 
blood-plasma. 

Blood-serum  is  a  sticky  liquid  which  is  more  alkaline  than  the  plasma. 
The  specific  gravity  in  man  is  1.027  to  1.032,  average  1.028.  The  color  is 
strongly  or  faintly  yellow;  in  human  blood-serum  it  is  pale  yellow  with  a 
shade  towards  green,  and  in  horses  it  is  often  amber-yellow.  The  serum  is 
ordinarily  clear;  after  a  meal  it  may  be  opalescent,  cloudy,  or  milky  white, 
according  to  the  amount  of  fat  contained  in  the  food. 

Besides  the  above-mentioned  bodies,  the  following  constituents  are  found 
in  tlie  blood-plasma  or  blood-serum  : 

Fat  occurs  from  1-7  p.  m.  in  fasting  animals.  After  partaking  of  food 
the  amount  is  increased  to  a  great  extent.  We  also  find  soa^js,  diolesterin, 
and  lecithin.  Cholesterin  occurs,  according  to  IIusthle,''  at  least  in  part  as 
fatty  acid  esters  {serolin  according  to  Boudet). 

Sugar  seems  to  be  a  physiological  constituent  of  the  plasma.  Accord- 
ing to  the  investigations  of  Abeles,  Ewald,  Kulz,  v.  Mering,  Seegen, 
and  MiUKA,'  the  sugar  found  in  the  plasma  is  glucose.     Otto  found  in  the 

'  Ueber  die  Darstellung  krystallinischer,  thierischer  Eiweissstoffe.  Inaug.-Diss. 
Slras.sburg,  1899. 

*  Zeilschr.  f.  physiol.  Chem.,  Bd.  21,  where  Boudet  is  also  cited. 

''  V.  Mcring,  Du  Bois-Reymond's  Archiv,  1877,  S.  379.  This  article  contains  numer- 
ous references  ;  Seegen,  Pfiuger's  Arch.,  Bd.  40;  Miura,  Zeitschr.  f.  Bioiogie,  Bd.  32. 


BLOOD  SERUM.  133 

plasma,  besides  glucose,  another  reducing,  non-fermentable  substance. 
According  to  Jacobsen  and  Henriques  '  this  substance  is  soluble  in  ether 
and  is  related  to  jecorin.  Bixg"  has  closely  studied  this  non-fermentable, 
reducing  substance  of  the  blood  and  considers  it  as  a  combination  of  sugar 
with  lecithin,  and  he  has  shown  that  a  mixture  of  lecithin  and  sugar  is 
soluble  in  ether  and  that  it  is  precipitable  by  alcohol  like  jecorin.  Accord- 
ing to  this  investigator  jecorin  is  also  a  combination  of  lecithin  with  glucose. 

Blood-plasma  as  well  as  lymph  contains,  according  to  Roiiman^n,  Bial 
and  IIamrurgei{,'  diastase,  which  converts  starch  and  glycogen  into 
maltose  or  isomaltose  and  a  cleavage  enzyme,  glucase  or  maltase,  which 
converts  maltose  into  glucose. 

Beiixard  *  has  shown  that  the  quantity  of  sugar  in  the  blood  diminishes 
more  or  less  rapidly  on  leaving  the  veins.  Lepixe,  associated  with  Barral, 
has  specially  studied  this  decrease  in  the  quantity  of  sugar  and  calls  it 
glycolysis.  Lepine  and  Barral,  as  well  as  Artiius,  have  shown  that  this 
glycolysis  takes  place  in  the  complete  absence  of  micro-organisms.  It  seems 
to  be  due  to  a  soluble  glycolytic  enzyme  whose  activity  is  destroyed  by  heat- 
ing to  -\-  54°  C.  This  enzyme  is  derived,  according  to  the  above  investiga- 
tors, from  the  leucocytes  and  is,  according  to  Lepixe,  delivered  from  the 
pancreas  to  the  blood.  According  to  Lepixe  it  is  formed  by  a  transforma- 
tion of  the  diastase,  but  this  is  not  so  according  to  Nasse  and  Framm  and 
Paderi."  The  glycolysis  is,  according  to  Nasse,  Kohmaxx  and  Spitz er,* 
an  oxidation  which  is  produced,  according  to  the  two  last-mentioned 
investigators,  by  an  oxidation  ferment.  It  is  surely  not  connected  with  the 
survival  of  the  cells,  but  whether  it  is  a  vital  or  a  post-mortem  process  is  not 
decided.'  In  the  glycolysis  produced  by  a  watery  extract  of  the  liver  Geza 
KowESY "  found  that  the  freezing-point  of  the  liquid  was  lowered  or  a 

'  Otto,  Pflliger's  Arch.,  35  (a  good  review  of  the  older  literature  on  sugar  in  the  blood), 
Jacobsen,  Ceiitralbl.  f.  Physiol.,  Bd.  6,  S.  36S;  Iknriqucs,  Zeitschr.  f.  physiol.  Chem., 
Bd.  23. 

*  Uudersogelser  over  reducereude  Subtanser  i  Blodet.    Kobenhaven,  1899. 

2  Rohmann  ;  Rohmanu  and  Hamburger,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  25 
and  27;  Pflliger's  Arch.,  Bdd.  52  and  60  ;  Bial,  Ueber  das  diast.  Ferm.,  etc.  Inaug.- 
Diss.  Breshiu,  1892  (older  literature).     See  also  PflUger's  Arch.,  Bdd.  52,  54,  and  55. 

*  Le9ons  sur  le  diabete.     Paris,  1877. 

*  In  regard  to  the  numerous  memoirs  of  Lepine  and  Lepiue  et  Barral,  see  Lyon  medi- 
cal, Tomes  62  and  63;  Compt.  rendus,  Tomes  110,  112,  113,  and  120;  Lepine,  Le  ferment 
glycolytique  et  la  pathogenie  du  diabfite  (Paris,  1891;,  and  Revue  analytiqne  et  critiques 
des  travaux,  etc.,  in  Arch,  de  med.  exper.  (Paris,  1892);  Revue  de  medecine,  1895; 
Arthus,  Arch,  de  Physiol.  (5),  Tomes  3,  4;  Nasse  and  Framm,  Pflliger's  Arch.,  63; 
Paderi,  Maly's  Jahresber.,  Bd.  26. 

«  See  Chapter  I. 

"  See  Arthus,  1.  c. ;  Colenbrander,  Maly's  Jahresber.,  22;  Rywosch,  Centralbl.  f. 
Physiol.,  Bd.  11,  S.  495. 

«  Centralbl.  f.  Physiol.,  Bd.  12. 


134  THE  BLOOD. 

higher  osmotic  pressure.  This  lowering  of  the  freezing-point,  which  is 
greatest  after  passing  oxygen  through,  depends  on  the  formation  of  an 
unknown  body,  which  does  not  distil  over  and  gives  at  least  one  of  tl.e 
acetone  reactions. 

Besides  the  mentioned  enzymes  we  have  also  in  the  serum,  according  to 
the  observations  of  Harriot  '  a  lipolytic  enzyms^  which  splits  neutral  fats. 
This  property  is  not  to  be  confounded  with  another,  observed  by  Cohnstein 
and  MicHAELis,^  which  consists  in  transforming  the  fat  (chyle-fat),  in  the 
presence  of  oxygen,  into  an  unknown  substance,  solnble  in  water.  This 
property  is  connected  with  the  form-elements  of  the  blood. 

The  serum  also  contains  bodies  of  an  unknown  kind  wtich  have  the  property  of  pr»~ 
venting  the  action  of  certain  enzymes  such  as  rennin,  pepsin,  and  trypsin.' 

Among  the  bodies  which  are  found  in  the  blood,  and  without  doubt  met 
with  in  smaller  or  greater  amounts  in  the  plasma,  are  to  be  mentioned  urea., 
uric  acid  (found  in  human  blood  by  Abeles^),  creati^i,  cao^hamic  acid, 
paralactic  acid,  and  Jiippiiric  acid.  Under  pathological  conditions  the 
following  bodies  have  been  found:  xanthin  bodies,  leucin,  tyrosin,  and 
liliary  constituents. 

The  coloring  matters  of  the  blood-serum  are  very  little  known.  In 
equine  blood-serum  biliary  coloring  matters,  bilirubin,  besides  other  coloring 
matters,  often  occar.  The  yellow  coloring  matter  of  the  serum  seems  to 
belong  to  the  group  of  luteins,  which  are  often  called  lipochromes  or  fat- 
coloring  matters.  From  ox-serum  Krukenberg  ^  was  able  to  isolate  with 
amyl  alcohol  a  so-called  hypochrome  whose  sokition  shows  two  absorption- 
bands,  of  which  one  encloses  the  line  F  and  the  other  lies  between  F  and  G. 

The  mineral  bodies  in  serum  and  plasma  are  qualitatively,  bat  not 
qaantitatively,  the  same.  A  part  of  the  calcium,  magnesium,  and  phos- 
phoric acid  is  removed  on  the  coagulation  of  the  fibrin.  By  means  of 
dialysis,  the  presence  of  sodium  chloride,  which  forms  the  chief  maas  or 
00-70/^  of  tlie  total  mineral  bodies,  also  lime-salts,  sodium  carbonate, 
besides  traces  of  sulphuric  and  phosphoric  acids  and  potassium,  may  be 
directly  shown  in  tlie  serum.*  Traces  of  silicic  acid,  fluorine,  copper,  iron, 
manganese,  and  ammonia  are  claimed  to  have  been  found  in  the  serum.  As 
in  most  animal  fluids,  the  chlorine  and  sodium  are  in  the  blood-serum  in 
excess  of  the  phosphoric  acid  and  potassium  (the  occurrence  of  which  in  the 
serum  is  even  doubted).  The  acids  found  in  the  ash  are  not  sufiicient  to 
saturate  the  bases  found,  a  condition  which  shows  that  a  part  of  the  bases 

'  Compt.  rend.  soc.  biol.,  Tome  48,  and  Compt.  rend.,  Tome  123. 

«  Pfluger's  Arch.,  Bdd.  65  u.  69. 

»  See  Kodeii,  Maly's  Jahresher.,  Bd.  17  ;  M.  Halm,  Berl.  klin.  Wochenscbr.,  Bd.  34. 

*  Wien.  med.  Jahrbiichcr,  1887. 

'  Sitzungsber.  d.  Jen.  Gesellscb.  f.  Med.,  1885. 

•  See  Giirber,  Verhandl.  d.  phys.-med.  Gesellsch.  zu  Wiirzburg,  Bd.  23. 


COMPOSITION  OF  PLASMA.  135 

is  combined  with  organic  substances,  perhaps  proteids.  This  coincides  also 
with  the  fact  that  tlie  great  part  of  the  alkalies  does  not  exist  in  the  serum 
as  diffusible  alkali  compounds,  carbonate  and  phosjihate,  but  as  non-diffusible 
compound,  proteid  combination.  According  to  llAMnuROER '  37^  of  the 
alkali  of  the  serum  from  horse-blood  was  diffusible  and  G3^  non-diffusible. 

The  gases  of  the  blood-serum,  which  consist  chiefly  of  carbon  dioxide 
with  only  a  little  nitrogen  and  oxygen,  will  be  described  when  treating  of 
the  gases  of  the  blood. 

Because  of  the  difficulty  of  obtaining  plasma  only  a  few  analyses  have 
been  made.  As  an  example  the  results  of  the  analyses  of  the  blood-plasma 
of  the  horse  will  be  given  below.  The  analysis  Xo.  1  was  made  by  IIoppk- 
Seyler.*  No.  2  is  the  average  of  the  results  of  three  analyses  made  by  the 
AUTHOR.     The  figures  are  given  in  1000  parts  of  the  plasma. 

No.  1.  No.  2. 

Water 908.4  917.6 

Solids 91.6  82.4 

Total  proteids  77.6  69.5 

Fibrin 10.1  6.5 

Globulin    38.4 

Seralbumin 24.6 

Fat 1.3]  - 

Extractive  substances 4.0  I  .^  q 

Soluble  salts 6.4  [  ^"'^ 

Insoluble  salts 1.7  J 

Abderhalden"  has  made  complete  analyses  of  blood-serum  of  several 
domestic  mammals.  From  these  analyses  as  well  as  from  those  made  by  the 
Author  of  the  serum  from  human,  horse,  and  ox-blood  it  follows  that  the 
amount  of  solids  ordinarily  varies  between  70-97  p.  m.  The  chief  mass  of 
the  solids  consists  of  proteids,  about  55-84  p.  m.  In  hens  the  author  found 
much  lower  values,  namely,  54  p.  m.  solids  with  only  30.5  p.  m.  proteid 
and  Halliburton  found  only  25.4  p.  m.  proteid  in  frog's  blood.  The 
relationship  between  globulin  and  seralbumin  is,  as  shown  by  the  analyses  of 
IIammarstex,  Halliburton,  and  Rubbrecht,'  very  different  for  different 
animals,  but  may  also  vary  considerable  in  the  same  variety  of  animal.  In 
human  blood-serum  the  author  found  more  seralbumin  than  globulin,  and 
the  relationship  of  serglobulin  to  seralbumin  was  as  1  :  1.5.  In  regard  to 
the  quantity  of  the  remaining  organic  constituents  of  the  serum  we  refer 
the  reader  to  Abdkrhalden's  complete  analyses  (page  171).  St.  Bugarsky 
iind  F.  Tangl*  have  determined  the  molecular  concentration  of  the  blood- 

'  In  regard  to  method  see  Du  Bois  Keymond's  Arch.,  1898. 

'  Cit.  from  v.  Gonip-Besanez's  Lehrbucli  der  physiol.  Chem.,  4.  Aufl..  p.  346. 

*  Abderhalden,  Zeitscbr.  f.  physiol.  Chem.,  Bd.  L'5 ;  Hammarsteu,  PHuger's  Arch., 
Bd.  17;  Halliburton  Jouru.  of  Physiol.,  Vol.  7;  Rubbrecht,  Travaux  du  laboratoire  de 
I'institut  de  physiolgie  de  Liege,  Tome  5,  1896. 

«  Pfliigers  Arch.,  Bd   73. 


136  THE  BLOOD. 

serani  of  certain  mammals,  and  find  that  it  has  only  a  slight  variation  ia 
different  animals,  about  0.320  mol.  per  litre.  They  also  found  that  about 
f  of  all  the  dissolved  molecules  of  the  blood-serum  are  electrolytes,  or  what 
amounts  to  the  same  thing,  are  inorganic,  and  that  correspondingly  the 
osmotic  pressure  of  blood-sernni  is  brought  about  chiefly  by  these  inorganic 
salts. 

The  quantity  of  mineral  bodies  in  the  serum  has  been  determined  by 
many  investigators.  The  conclusions  drawn  from  the  analyses  is  that  there 
exists  a  rather  close  correspondence  between  human  and  animal  blood- 
serum,  and  it  is  therefore  sufficient  to  giv^e  here  the  analysis  of  C.  Schmidt  * 
of  (1)  human  blood,  and  Buxge  and  Abderhalden's  analyses  of  serum  of 
ox,  bull,  sheep,  goat,  pig,  rabbit,  dog,  and  cat.  The  results  correspond  to 
1000  parts  by  weight  of  the  serum. 

1  2 

K,0 0.387-0.401  0.226-0.270 

NaaO 4.290-4.290  4.251-4.442 

CI 3.565-3.659  3.627-4.170 

CaO 0.155-0.155  0.110-0.131 

MgO 0.101 0.040-0.046 

PaOs  (inorg.) 0.052-0.085 

The  amount  of  NaCl  is  about  G  p.  m.,  and  it  is  remarkable  that  this 
amount  of  XaCl  remains  constant,  so  that  with  food  containing  an  excess 
of  XaCl  it  is  quickly  eliminated  by  the  urine,  and  with  food  "poor  in 
chlorides  the  amount  in  the  blood  first  decreases,  but  increases  after  taking 
chlorides  from  the  tissues.  The  secretion  of  chlorides  by  the  urine  is 
thereby  diminished. 

II.  The  Forni-eleiTieiits  of  the  Blood. 

The  Red  Blood-corpuscles. 

The  blood-corpuscles  are  round,  biconcave  disks  without  membrane  and 
nucleus  in  man  and  mammalia  (with  the  exception  of  the  llama,  the  camel, 
and  their  congeners).  In  the  latter  animals,  as  also  in  birds,  amphibia,  and 
fishes  (with  the  exception  of  the  cyclostoma),  the  corpuscles  have  in  general 
a  nucleus,  are  biconvex  and  more  or  less  elliptical.  The  size  varies  in 
different  animals.  In  man  they  have  an  average  diameter  of  7  to  8  // 
{lA  =  0.001  mm.)  and  a  maximum  thickness  of  l.Oyu.  They  are  heavier 
than  the  blood-plasma  or  serum,  and  therefore  sink  in  these  liquids.  In 
the  discharged  blood  they  may  lie  sometimes  with  their  flat  surfaces 
together,  forming  a  cylinder  like  a  roll  of  coin.  The  reason  for  this  is 
unknown,  but  as  it  may  be  observed  in  defibrinated  blood  it  seems  probable 
that  the  formation  of  fibrin  has  nothing  to  do  with  it.  On  account  of  the 
different  buoyancy  of  the  blood-corpuscles  in  defibrinated  and  not  defibri- 

'  Cit.  Hoppe-Seyler's  Physiol,  riieni.,  1881,  S.  439. 


RED    CORPUSCLES.  137 

iiated  blood  has  lead  Bieunacki  '  to  the  view  that  the  blood-corpnscles  in 
living  blood  contain  plasma  in  their  interior  and  give  this  out  on  death. 

The  number  of  red  blood-corpuscles  is  different  in  the  blood  of  various 
animals.  In  the  blood  of  man  there  are  generally  5  million  red  corpuscles 
in  1  c.mm.,  and  in  woman  4  to  4.5  million. 

On  diluting  the  blood  with  water  and  alternately  freezing  and  thawin<T 
it,  as  also  on  shaking  it  with  ether,  or  by  the  action  of  chloroform  or  biU\ 
a  remarkable  change  takes  place.  Tbe  blood-coloring  matters,  which  arc 
hardly  free  in  the  blood-corpuscles,  but  are,  rather,  combined  with  some 
other  substance,  are  by  this  means  set  free  and  pass  into  solution,  while  the 
remainder  of  each  blood-corpuscle  forms  a  swollen  mass.  By  the  action  of 
carbon  dioxide,  by  the  careful  addition  of  acids,  acid  salts,  tincture  of 
iodine,  or  certain  other  bodies,  this  residue,  rich  in  proteids,  condenses  and 
in  many  cases  the  form  of  the  blood-corpuscles  may  be  again  obtained. 
This  residue  has  been  called  the  stroma  of  the  red  blood-corpuscles. 

To  isolate  the  stromata  of  the  blood-corpuscles  they  are  washed  first  by 
diluting  the  blood  with  10-20  vols,  of  a  l-S,'^  common-salt  solution  and 
then  separating  the  mixture  by  centrifugal  force  or  by  allowing  it  to  stand 
at  a  low  temperature.  This  is  repeated  a  few  times  until  the  blood- 
corpnscles  are  freed  from  serum.  These  purified  blood-corpuscles  are, 
according  to  AVooldridge,  mixed  with  5-G  vols,  of  water  and  then  a  little 
ether  is  added  until  complete  solution  is  obtained.  The  leucocytes 
gradually  settle  to  the  bottom,  a  movement  which  may  be  accelerated  by 
centrifugal  force,  and  the  liquid  which  separates  therefrom  is  very  carefully 
treated  with  a  1,'^  solution  of  KHSO^  until  it  is  about  as  dense  as  the  orig- 
inal blood.  The  separated  stromata  are  collected  on  a  filter  and  quickly 
washed. 

WooLDiiiDGi:  found  as  constituents  of  the  stroma  lecithin.,  chohsterin, 
micleoalbionin,  and  a  globulin  which,  according  to  Halliburton,  is  prob- 
ably a  nucleoproteid  which  he  calls  cell-fflobidin.  The  cholesterin  contained 
in  the  blood-corpuscles  is  free,  according  to  IIepxer.*  The  blood-corpus- 
cles do  not  contain  fatty  acid  cholesterin  ester.  Plasma  contains  besides 
such  esters  also  free  cholesterin.  No  nuclein  substances  or  seralbumin  or 
albumoses  could  be  detected  by  IIalliburtox  and  Friexd.  The  nucleated 
red  blood-corpuscles  of  the  bird  contain,  according  to  Plosz  and  IIoppe- 
Seyler,^  nuclein  and  an  albuminous  body  which  swells  to  a  slimy  mass  in  a 
10^  common-salt  solution,  and  which  seems  to  be  closely  related  to  the 
hyaline  substance  {hyaline  substance  of  Rovida)  occurring  in  the  lymph- 

>  Zeitschr.  f.  physiol.  Chem..  Bdd.  19  and  23. 

'PaUger's  Arcli.,  Bd.  73. 

»  "Wooldiidge,  Dii  Bois-Reymond's  Arclilv.,  1881,  S.  387  ;  Halllburtou  aud  Friend, 
Journal  of  Physiol.,  Vol.  10;  Halliburton,  ibid.,  Vol.  18;  Iloppe-Seyler's  Med.  chem. 
Uutersuch.,  S.  510. 


138  THE  BLOOD. 

cells.  The  red  blood-corpnscles  without  any  nucleus  are,  as  a  rule,  very 
poor  in  proteid  but  are  rich  in  haemoglobin;  the  nucleated  corpuscles  are 
richer  in  proteid  and  poorer  in  hfemoglobin. 

A  gelatinous,  fibrin-like  proteid  body  may  be  obtained  from  the  red 
blood-corpuscles  under  certain  circumstances.  This  fibrin-like  mass  hag 
been  observed  on  freezing  and  then  thawing  the  sediment  of  the  blood- 
corpuscles,  or  on  discharging  the  spark  from  a  large  Leyden  jar  through 
the  blood,  or  on  dissolving  the  blood -corpuscles  of  one  kind  of  animal  in 
the  serum  of  another  (Landois,  stroma-fibrin).  In  none  of  these  cases  has 
it  been  shown  that  we  have  to  deal  with  a  fibrin  formation  at  the  expense 
of  the  stroma.  It  seems  only  to  have  been  shown  that  the  red  blood- 
corpuscles  of  frog's  blood  contain  fibrinogen  (Alex.  Schmidt  and 
Semmer'). 

The  mineral  bodies  of  the  red  corpuscles  will  be  treated  of  in  connection 
with  the  quantitative  constitution  of  the  same. 

The  most  important  constituent  of  the  blood-corpuscles  from  a  j^hysio- 
logical  standpoint  seems  to  be  the  red  coloring  matter. 

/  Blood-coloring  Matters. 

According  to  Hoppe-Seyler '•*  the  coloring  matter  of  the  red  blood- 
cori^uscles  is  not  in  a  free  state,  but  combined  with  some  other  substance. 
The  crystalline  coloring  matter,  the  hsemoglobin  or  oxyhgemoglobin,  which 
may  be  isolated  from  the  blood,  is  considered,  according  to  IIoppe-Seyler, 
as  a  cleavage  product  of  this  combination,  and  it  acts  in  many  ways  unlike 
the  questionable  combination  itself.  This  combination  is  insoluble  in 
water  and  uncrystallizable.  It  strongly  decomposes  hydrogen  peroxide 
without  being  oxidized  itself;  it  shows  a  greater  resistance  to  certain 
chemical  reagents  (as  potassium  ferricyanide)  than  the  free  coloring  matter, 
and  lastly  it  gives  off  its  loosely  combined  oxygen  much  more  easily  in 
vacuum  than  the  free  pigment.  To  distinguish  between  the  cleavage 
products,  the  hemoglobin  and  the  oxyhgemoglobin,  Hoppe-Seyler  calls 
the  combination  of  the  blood-coloring  matter  of  the  venous  blood-corpuscles 
phlebin,  and  that  of  the  arterial  arterin.  Since  the  above-mentioned  com- 
bination of  tlie  blood-coloring  matters  Avith  other  bodies,  for  example  (if 
they  really  do  exist)  with  lecithin,  have  not  been  closely  studied,  the  follow- 
ing statements  will  only  apply  to  the  free  pigment,  the  hamioglobin. 

The  color  of  the  blood  depends  in  part  on  hmmo(jlobin  or  fseudo- 
ItcBmoglobin  (see  below),  and  in  part  on  a  molecular  combination  of  this 
with  oxygen,  the  oxjjhwDioghbin.  We  find  in  blood  after  asphyxiation 
almost  exclusively  hajmoglobin  (and  pseudo-haBmoglobin),  in  arterial  blood 

'  Liindois,  Centralbl.  f.  d.  med.  Wisseusch.,  1874,  S.  421;  Schmidt,  PflUger's  Arch., 
Bd.  11,  S.  S.jO-oo'J. 

'  Zeitschr.  f.  physiol.  Chcm.,  Bd.  i:j,  S.  479. 


IIuEMOGLOn/yS. 


139 


disproportionately  large  amounts  of  oxylia'moglobin,  and  in  venous  blood  a 
mixture  of  both.  Blood-coloring  matters  are  found  also  in  striated  as  well 
as  in  certain  smooth  muscles,  and  lastly  in  solution  in  dilferent  inverte- 
brates. The>  quantit}'  of  ha'moglobin  in  human  blood  may  indeed  be 
somewhat  variable  under  different  circumstances,  but  amounts  to  about 
1^^  on  an  average,  or  8.5  grammes  have  been  determined  for  each  kilo  of 
the  weight  of  the  body. 

TLv>moglobin  belongs  to  the  group  of  compound  proteids,  and  yields  as 
cleavage  products,  besides  very  small  amounts  of  volatile  fatty  acids  and 
other  bodies,  c\iief\y  prof e id  and  a  coloring  matter,  hnmorlironiogen  (about 
4j^),  containing  iron,  which  in  the  presence  of  oxygen  is  easily  oxidized 
into  hiematin.  Lawkow  '  obtained  94.09^^  proteid,  4.47^^  haematin,  and 
1.44^'  other  constituents  on  the  cleavage  of  oxyha?moglobin.  He  considers 
the  proteid,  which  was  not  soluble  in  ammonia,  and  which  gave  a  precipi- 
tate with  nitric  acid  which  dissolved  on  warmrng  as  a  special  protein 
substance. 

As  suggested  by  Hoppe-Sevler,  and  later  shown  by  Schltnck  and 
Marchlewski  a  close  relationship  exists  between  chlorophyll  and  the  blood 
l^igment  because  a  derivative  of  the  first,  phylloporphyrin,  stands  very  close 
in  certain  regards  to  a  derivative  of  the  blood  pigment,  ha?motoporphyrin. 
Both  bodies  give  the  pyrol  reaction  and  both  seem  to  be  constructed  from 
a  mother-substance,  whose  great  biological  importance  has  been  developed 
by  Nencki.' 

The  haemoglobin  prepared  from  different  kinds  of  blood  has  not  exactly 
the  same  composition,  which  seems  to  indicate  the  presence  of  different 
haemoglobins.  The  analyses  of  different  investigators  of  the  haemoglobin 
from  the  same  kind  of  blood  do  not  always  agree  with  one  another,  which 
probably  depends  upon  the  somewhat  various  methods  of  preparation.  The 
following  analyses  are  given  as  examples  of  the  constitution  of  different 
hfemosclobins: 


Hsenioglobin  from  the     C 

Dog 53.85 

"     54.57 

Horse 54.87 

"      51.15 

0.\ 54.66 

Pig 54.17 

"     54.71 

Guinea-pig 54.12 

Squirrel   54.09 

Goose 54.26 

Heu 52.47 


H 

N 

S 

Fe 

7.32 

16.17 

0.390 

0.430 

7.22 

16.38 

0.568 

0.336 

6.97 

17.31 

0.6.00 

0.470 

6.76 

17.94 

0.390 

0  335 

7.25 

17.70 

0.447 

0.400^ 

7.38 

16.23 

0.660 

0.430 

7.38 

17.43 

0.479 

0.399 

7.36 

16.78 

0.580 

0.480 

7.39 

16.09 

0.400 

0.590 

7.10 

16.21 

0..540 

0.430 

7.19 

16.45 

0.857 

0.335 

O  P.O* 

2 1 .  84  (HopPE-Se  YLER) 

20  93  (Jaquet) 

19.73  (KossEL) 

23.43  (ZiNOFKSKY) 

0.400*  19.543  (HuFNEK) 

21.360  (Otto) 

19.602  (Hi-FXEK) 

20.680  (Hoppe-Seyler) 

21.440  

20.690  0.77 

22.500  0.197  (Jaquet) 


*  Accordiug  to  more  receut  deterniiuutious  of  Hufner  and  J.\qdet  (Du  Bois-Rey- 
mond's  Arch.,  1894,  S.  175),  the  quantity  of  iron  in  ox- haemoglobin  is  0.336^  (average  of 
5  analyses). 

•  Zeit-schr.  f.  pliysiol.  Chem.,  Bd.  26. 

'  Schunck  and  Marchlewski,  Ann.-il.  d.  Cheui.  u. 
■Neucki,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  29. 


Pharm.,    Bdd.  278,  284,   288.   290; 


140  THE  BLOOD. 

The  question  whether  the  amount  of  phosphorus  in  the  hsemoglobin 
from  birds  exists  as  a  contamination  or  as  a  constituent  has  not  been 
decided.  According  to  Inoko  the  haemoglobin  from  goose's  blood  consists 
of  a  combination  between  nucleic  acid  and  hfemoglobin.  In  the  hsemo- 
globin  from  the  horse  (Zixoffsky),  the  pig,  and  the  ox  (Hufner)  we  have 
1  atom  of  iron  to  2  atoms  of  sulphur,  while  in  the  haemoglobin  from  the 
dog  (Jaquet)  the  relation  is  1  to  3.  From  the  data  of  the  elementary 
analysis,  as  also  from  the  amount  of  loosely  combined  oxygen,  Hufxer  * 
has  calculated  the  molecular  weight  of  dog-haemoglobin  as  14,129  and  the 
formula  C,33lI,j,„^X,j^FeS30jgj.  The  molecular  weight  is  therefore  very 
high.  The  haemoglobin  from  various  kinds  of  blood  not  only  shows  a 
diverse  constitution,  but  also  a  different  solubility  and  crystalline  form,  and 
a  varying  quantity  of  water  of  crystallization;  hence  we  infer  that  there  are 
several  kinds  of  haemoglobin.  Bohr  is  a  very  zealous  advocate  of  thia 
supposition.  He  has  been  able  to  obtain  haemoglobin  from  dog  and  horse 
blood,  by  fractional  crystallization,  which  had  different  power  of  combining 
with  oxygen  and  containing  different  quantities  of  iron.  Hoppe-Setler 
had  already  jarepared  two  different  forms  of  hgemoglobin  crystals  from 
horse's  blood,  and  Bohr  concludes  from  a  collection  of  these  observations 
that  the  ordinary  hsemoglobin  consists  of  a  mixture  of  different  haemo- 
globins. In  opposition  to  this  statement  Hufner''  has  shown  that  only 
one  hcemoglobin  exists  in  ox-blood,  and  that  this  is  probably  true  for  the 
blood  of  many  other  animals. 

Oxyhsemoglobin,    which    has    also    been   called    h.ematoglobulix   or 

H^MATOCRTSTALLiN,    is    a    molccular    combination    of    hsemoglobin    and 

oxygen.     For  each  molecule  of  hsemoglobin  1  molecule  of  oxygen  exists; 

and  the  amount  of  loosely  combined  oxygen  which  is  united  to  1  grm. 

hsemoglobin   (of  the  ox)  has  been  determined  by  PIufner^  as  1.34  c.c. 

(calculated  at  0°  C.  and  7G0  mm.  mercury). 

According  to  Bohr,  the  facts  are  different.  He  differentiates  between  four  different 
oxyhsemoglobins,  according  to  the  quantity  of  oxygen  wliich  they  absorb,  namely,  a-,  /3,- 
y-,  and  (5-oxyhsemoglobin,  all  having  the  same  absorption-spectrum  and  1  gm.  combin- 
ing with  respectively  0.4,  0.8,  1.7,  and  2.7cc.  oxygen  at  the  temperature  of  the  room  and 
with  an  oxygen  pressure  of  150  mm.  mercury.  The  T^-oxyha^moglobin  is  the  ordinary 
one  obtained  by  the  customary  method  of  preparation.  Bomi  designates  as  a-oxyhae- 
moglobin  the  crystalline  powder  obtained  by  drying  ;K-oxyliiemoglol)in  in  the  air.  On 
dissolving  a-oxyhu;moglobin  in  water  it  is  converted  into  /S-bajmoglobin  without  decom- 


'  Hoppe-Seyler,  Med.  chem.  Untersuch.,  S.  370  ;  Jaquet,  Zeitschr.  f.  physiol.  Chem., 
Bd.  14,  S.  296;  Kossel,  ibid.,  Bd.  2,  S.  150;  Zinoffsky,  ihid.,  Bd.  10;  Hiifner.  Beitr. 
z.  Pliysiol..  Festschr.  f.  C.  Ludwig,  1887,  S.  74-81,  Journ.  f.  prakt.  Ciiem.  (N.  F.), 
Bd.  22;  Otto,  Zeitschr.   f.  physiol.  Chem.,  Bd.  7,  S.  01  ;  Inoko,  ihid.,  Bd.  18. 

'  "  Sur  les  combinaisons  de  rhemoglobine  avec  I'oxygtine."  Extrait  du  Bulletin  de 
I'Academie  Royale  Danoise  des  sciences,  1890;  also  Centralbl.  f.  Physiol.,  1890,  S.  249; 
Hoppe-Seyler,  Zeitschr.  f.  physiol.  Chem.,  Bd.  2-  Hufner,  Du  Bois-Reymond's  Arch., 
1894. 

*  Du  Bois-Reymond's  Arch.,  1894. 


ox  YH^^MO  OL  OBIN.  1 4 1 

posiliou,  and  the  quantity  of  iron  is  iucrcased.  On  keeping  a  solution  of  ^-oxyha'mo- 
globiu  in  a  sealed  tube  it  is  transformed  into  ^-oxybseinoglobin,  although  the  circum- 
stances of  this  change  are  not  known.  According  to  Hiifner'  these  are  nothing  but  u 
mixture  of  genuine  and  partly  decomposed  hsemoglobius. 

The  ability  of  hfemoglobiu  to  take  up  oxygen  seems  to  be  u  function  of 
the  iron  it  contains,  and  when  this  is  calculated  as  about  0.33-0. 40j^,  then 
1  atom  of  iron  in  the  htemoglobin  corresponds  to  about  2  atoms  =  1  mole- 
cule of  oxygen.  'J'he  combination  of  haemoglobin  with  oxygen  is,  as  has 
been  stated,  loose  and  dissociatable,  and  the  quantity  of  oxygen  taken  up 
by  a  hsemoglobin  solution  depends  upon  the  partial  pressure  of  the  oxygen 
at  that  tenijierature.  If  this  latter  be  decreased  by  means  of  a  vacuum, 
especially  on  gently  heating  or  by  passing  some  indifferent  gas  through  the 
solution,  all  of  the  oxygen  may  be  exjielled  from  an  oxyhsemoglobin  solution 
so  that  only  haemoglobin  remains.  The  reverse  of  this  is  true  of  a  haemo- 
globin solution  which  by  its  remarkable  attraction  for  oxygen  may  be 
converted  into  oxyhajnioglobin.  Oxyhtemoglobin  is  generally  considered  as 
a  weak  acid. 

Oxyhaemoglobin  has  been  obtained  in  crystals  from  several  varieties  of 
blood.  These  crystals  are  blood-red,  transjjarent,  silky,  and  may  be  2-3 
mm.  long.  The  oxyhaemoglobin  from  squirrel's  blood  crystallizes  in  six- 
sided  plates  of  the  hexagonal  system;  the  other  varieties  of  blood  yield 
needles,  prisms,  tetrahedra,  or  jilates  which  belong  to  the  rhombic  system. 
The  quantity  of  water  of  crystallization  varies  between  3-10^  for  the 
different  oxyhemoglobins.  When  completely  dried  at  a  low  temperature 
over  sulphuric  acid  the  crystals  may  be  heated  to  110-115°  C.  without 
decomposing.  At  higher  temperatures,  somewhat  above  160°  C,  they 
decompose,  giving  an  odor  of  burnt  horn,  and  leave,  after  complete  com- 
bustion, an  ash  consisting  of  oxide  of  iron.  The  oxyhasmoglobin  crystals 
from  difficultly  crystallizable  kinds  of  blood,  for  example  from  such  as  ox's, 
human,  and  pig's  blood,  are  easily  soluble  in  water.  The  oxylijemoglobin 
from  easily  crystallizable  blood,  as  from  that  of  the  horse,  dog,  squirrel, 
and  guinea-i)ig,  are  soluble  with  difficulty  in  the  order  above  given.  The 
oxyhemoglobin  dissolves  more  easily  in  a  very  dilute  solution  of  alkali  car- 
l)oiiate  than  in  pure  water,  and  this  solution  may  be  kept.  The  presence 
of  a  little  too  much  alkali  causes  the  oxyhemoglobin  to  quickly  decompose. 
The  crystals  are  insoluble  without  decolorization  in  absolute  alcohol. 
According  to  Np:xcki,^  it  is  hereby  converted  into  an  isomeric  or  polymeric 
modification,  called  by  him  imralimmofjlobin.  Oxyhemoglobin  is  insoluble 
in  ether,  chloroform,  benzol,  and  carbon  disulphide. 

A  solution  of  oxyhemoglobin  in  water  is  precipitated  by  many  meti^llic 
salts,  but  is  not  precipitated  by  sugar  of  lead  or  basic  lead  acetate.     On 

'  Du  Bois-Reyraond's  Archiv,  1884. 

'  Nencki  and  Sieber,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  18. 


142  THE  BLOOD. 

heating  the  watery  sohition  it  decomposes  at  G0°  to  TO""  C,  and  it  splits  off 
proteid  and  hasmatin.  It  is  also  readily  decomposed  by  acids,  alkalies,  and 
many  metallic  salts.  It  gives  the  ordinary  reactions  for  proteids,  with  the 
ordinary  proteid  reagents  which  first  decompose  the  oxyhasmoglobin  with 
the  splitting  off  of  proteid. 

The  oxyha?mogIobin  may,  when  it  is  gradually  oxidized,  act  as  an 
"ozone  exciter"  by  the  decomposition  of  neutral  oxygen,  converting  it 
into  active  oxygen  (Pfluger').  It  may  also  have  another  relation  to 
ozone,  since  it  has  the  property  of  an  "  ozone  transmitter  "  in  that  it  causes 
the  reaction  of  certain  reagents  (turpentine)  containing  ozone  upon  ozone 
reagents  such  as  tincture  of  gnaiacum. 

A  sufficiently  dilate  solution  of  oxy haemoglobin  or  arterial  blood  shows 
a  spectrnm  with  two  absorption-bands  between  the  Fraunhofer  lines  D 
and  E.  The  one  band,  a,  which  is  narrower  but  darker  and  sharper,  lies 
on  the  line  D;  the  other,  broader,  less  defined  and  less  dark  band,  /?,  lies 
at  E.  These  bands  can  be  detected  in  a  layer  of  1  cm.  thick  of  a  0.1 
p.  m.  solution  of  oxyhaemoglobin.  In  a  still  weaker  dilution  the  band  ^ 
first  disappears.  By  increased  concentration  of  the  solution  the  two  bands 
become  broader,  the  space  between  them  smaller  or  entirely  obliterated,  and 
at  the  same  time  the  blue  and  violet  part  of  the  spectrum  is  darkened. 
The  oxyhsemoglobin  may  be  differentiated  from  other  coloring  matters 
having  a  similar  absorption-spectrum  by  its  behavior  towards  reducing  sub- 
stances.    (See  below.)* 

A  great  many  methods  have  been  proposed  for  the  preparation  of 
oxyhsemoglobin  crystals,  bat  in  their  chief  features  they  all  agree  with  the 
following  method  as  suggested  by  Hoppe-Setler:  The  washed  blood- 
corpuscles  (best  those  from  the  dog  or  the  horse)  are  stirred  with  2  vols, 
water  and  then  shaken  with  ether.  After  decanting  the  ether  and  allowing 
the  ether  which  is  retained  by  the  blood  solution  to  evaporate  in  an  open 
dish  in  the  air,  cool  the  filtered  blood  solution*  to  0°  C,  add  while  stirring 
^  vol.  of  alcohol  also  cooled,  and  allow  to  stand  a  few  days  at  —  5°  to 
—  10'^  C.  The  crystals  which  separate  may  be  repeatedly  recrystallized  by 
dissolving  in  Avater  of  about  35°  C,  cooling  and  adding  cooled  alcohol  as 
above.  Lastly,  they  are  washed  with  cooled  water  containing  alcohol 
(\  vol,  alcohol)  and  dried  in  vacnnm  at  0°  C.  or  a  lower  temperature. 
According  to  Gschkidlkx's^  investigations,  oxyhaemoglobin  crystals  may 
be  obtained  from  diificultly  crystallizable  varieties  of  blood  by  allowing  the 
blood  first  to  putrefy  slightly  in  sealed  tubes.  After  shaking  with  air  by 
which  the  blood  is  again  arterialized,  proceed  as  above. 

For  the  preparation  of  oxyhaemoglobin  crystals  in  small  quantities  from 

'  Pfluger's  Arch.,  Bd.  10. 

'  Iloppe-Seylor,  Med.-cliem.  Untersucli.,  S.  181  ;  Gsclieidlcn,  Pfluger's  Arch.,  Bd.  16. 

*  Zeitschr.  f.  Biologic,  Bd.  34,  contains  the  investigations  of  Gamgee  on  the  absorp- 
tion of  the  ultraviolet  rays  by  the  blood  pigment.  It  also  contains  some  of  the  earlier 
investigations. 


HEMOGLOBIN.  143 

blood  easily  crystallized,  it  is  often  siillicieiit  to  stir  a  drop  of  blood  with  a 
little  water  on  a  microscope  slide  and  allow  the  mixture  to  evaporate  so  that 
the  drop  is  surrounded  by  a  dried  ring.  After  covering  with  a  thin  glass, 
tlie  crystals  gradually  appear  radiating  from  the  ring.  These  crystals  are 
formed  in  a  surer  manner  if  the  blood  is  first  mixed  witli  some  water  in  a 
test-tube  and  shaken  with  ether  and  a  drop  of  the  lower  deep-colored  liquid 
treated  as  above  on  the  slide. 

Haemoglobin,  also  called  reduced  n.EMOGLoiu.v  or  puri'Li:  (.ituoKiN' 
(Stokes'),  occurs  only  in  very  small  ([uantities  in  arterial  blood,  in  larger 
(juan titles  in  venous  blood,  and  is  nearly  the  only  blood-coloring  matter 
after  asphyxiation. 

Haemoglobin  is  much  more  soluble  than  the  oxyhaemoglobin,  and  it  can 
therefore  only  be  obtained  as  crystals  with  ditticulty.  These  crystals  are  as 
a  rule  isomorphous  to  the  corresponding  oxyhicmoglobin  crystals,  but  are 
darker,  having  a  shade  towards  blue  or  purple,  and  are  decidedly  more 
pleochromatic.  Its  solutions  in  vrater  are  darker  and  more  violet  or 
purplisb  than  solutions  of  oxyhemoglobin  of  the  same  concentration.  They 
absorb  the  blue  and  the  violet  rays  of  the  spectrum  in  a  less  marked  degree, 
but  strongly  absorb  the  rays  lying  between  C  and  D.  In  proper  dilution 
the  solution  shows  a  spectrum  with  one  broad,  not  sharply  defined  band 
between  D  and  E.  This  band  does  not  lie  in  the  middle  between  D  and  Ey 
but  is  towards  the  red  end  of  the  spectrum,  a  little  over  the  line  D.  A 
hsemoglobin  solution  actively  absorbs  oxygen  from  the  air  and  is  converted 
into  an  oxy haemoglobin  solution. 

A  solution  of  oxyhaBinoglobin  may  be  easily  converted  into  a  solution 
having  the  spectrum  of  luemoglobiu  by  means  of  a  vacuum,  by  passing  an 
indiiferent  gas  through  it,  or  by  the  addition  of  a  reducing  sul)stance,  as, 
for  example,  an  ammoniacal  ferro-tartrate  solution  (Stokes'  reduction- 
liquiil).  If  an  oxyhaemoglobin  solution  or  arterial  blood  is  kept  in  a  sealed 
tube,  we  observe  a  gradual  consumption  of  oxygen  and  a  reduction  of  the 
oxyhiemoglobin  into  haemoglobin.  If  the  solution  has  a  proper  concentra- 
tion, a  crystallization  of  haemoglobin  may  occur  in  the  tube  at  lower  tem- 
peratures (HCfxek'). 

Pseudohaenxoglobin.  Ludwig  Jiiid  Siegfried  ^  have  observed  that  blood  which  has 
been  icdnceil  by  hyposulphites  so  completely  that  the  oxylifemoglobiu  s|)ectruiu  disap- 
pt-ars  ami  oidy  the  hoeiu().irlol)in'spectniin  is  seen  yields  large  amouuls  of  oxygen  when 
(txposed  to  a  vacuum.  Blood  which  has  been  reduced  by  the  passage  of  a  stream  of 
iiydrogen  through  il  until  the  oxyhtemoglobin  spectrum  disappears  acts  in  the  same 
mannrr.  Hence  a  loose  combination  of  litcmoglobin  and  oxygen  exists  which  gives  the 
hieinogiobin  spectrum,  and  this  combination  is  called  pseudohirmoglobin  by  Lonwia 
and  SiKUKiiiKi).  Pseudohicmoglobin,  whose  presence  has  been  delecteii  in  asphyxiation 
blood  from  dogs,  is  considered  by  the  author  as  an  intermediate  step  between  htemo- 
glol)in  and  oxyhneinoglobin  on  the  reduction  of  the  latter.  The  occurrence  of  pseudo- 
haemoglobin  seems  not  to  have  been  positively  proved.^ 

'  Philosophical  Magazine,  Vol.  28,  No.  190,  Nov.  1864. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  4. 

'  Du  Bois-Ueymond's  Archiv,  1890 ;  see  also  Ivo  Novi,  PHiiger's  Archiv,  Bd.  56. 

*  See  Hufutr.  Du  Bois-Reymoud's  Arch.,  1894,  S   140. 


144  THE  BLOOD. 

Methsemoglobin.  This  name  has  been  given  to  a  coloring  matter  which 
is  easily  obtained  from  oxyhsemoglobin  as  a  transformation  product  and 
which  has  been  correspondingly  found  in  transudations  and  cystic  fluids 
containing  blood,  in  urine,  in  hsematuria  or  hasmoglobinuria,  also  in  urine 
and  blood  on  poisoning  with  potassium  chlorate,  amyl  nitrite  or  alkali 
nitrite,  and  many  other  bodies. 

Methffimoglobin  does  not  contain  any  oxygen  in  molecular  or  dissociable 
combination,  but  still  the  oxygen  seems  to  be  of  importance  in  the  forma- 
tion of  methsemoglobin,  because  it  is  formed  from  oxyhsemoglobin  in  the 
absence  of  oxygen  or  oxidizing  agents,  and  not  from  haemoglobin.  If 
arterial  blood  be  sealed  up  in  a  tube,  it  gradually  consumes  its  oxygen  and 
becomes  venous,  and  by  this  absorption  of  oxygen  a  little  methsemoglobin 
is  formed.  The  same  occurs  on  the  addition  of  a  small  quantity  of  acid  to 
the  blood.  By  the  spontaneous  decomposition  of  blood  some  methsemo- 
globin is  formed,  and  by  the  action  of  ozone,  potassium  permanganate, 
potassium  ferricyanide,  chlorates,  nitrites,  nitrobenzol,  pyrogallol,  pyro- 
catechin,  acetanilid,  and  certain  other  bodies  on  the  blood  an  abundant 
formati^an  of  methsemoglobin  takes  place. 

According  to  the  investigations  of  Hufxer,  Kulz,  and  Otto  methsmo- 
globin  contains  just  as  much  oxygen  as  oxyhsemoglobin,  but  it  is  more 
strongly  combined.  According  to  Haldane  methsemoglobin  contains  two 
combined  ox3^gen  atoms,  while  in  oxyhemoglobin  an  oxygen  molecule  is 

united.     Owhaemoglobin  Hb^    |  and  methsemoglobin  Hb  \    .     Jadeeholm 

^0  ^0 

and  Saarbach  claim  that  a  methsemoglobin  solution  is  first  converted  into 
an  oxvh^moglobin  and  then  into  a  hsemoglobin  solution  by  reducing  sub- 
stances, while  Hoppe-Seyler  and  Araki  '  claim  that  it  is  converted 
directly  into  a  hsemoglobin  solution. 

Methsemoglobin  crystallizes  as  first  shown  by  Hufner  and  Otto  in 
brownish-red  needles,  prisms,  or  six-sided  plates.  It  dissolves  easily  in 
water;  the  solution  has  a  brown  color  and  becomes  a  beautiful  red  on  the 
addition  of  alkali.  The  solution  of  the  pure  substance  is  not  precipitated 
by  basic  lead  acetate  alone,  but  by  basic  lead  acetate  and  ammonia.  The 
absorption-spectrum  of  a  watery  or  acidified  solution  of  methsemoglobin  is, 
according  to  Jaueriiolm  and  Bertin-Sans,  very  similar  to  that  of 
htematin  in  acid  solution,  but  is  easily  distinguished  from  the  latter  since, 
on  the  addition  of  a  little  alkali  and  a  reducing  substance,  the  former 
passes  over  to  the  spectrum  of  reduced  haemoglobin,  while  a  hsematin  solu- 
tion under  the  same  conditions  gives  the  spectrum  of  an  alkaline  hsemo- 


1  Otto,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  7  ;  Haldaue,  Journ.  of  Physiol.,  Vol.  23; 
Jiiderbolm,  Zeitscbr.  f.  Biologic,  Bd.  16;  Snarbacb,  Ptlagcr's  Arcb.,  Bd.  28;  Aiaki, 
Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  14. 


CARBON  MONOXIDE  IL^MOOLOBIN.  145 

cliromogen  solution  (see  below).  Methaemoglobin  in  alkaline  solntion  shows 
two  absorption-bands  which  are  like  the  two  oxyhx'nioglobin  bands,  but 
they  diller  from  these  in  that  the  band  ft  is  stronger  than  a.  By  the  side 
of  the  band  a  and  united  with  it  by  a  shadow  lies  a  third,  fainter  band 
between  C  and  D,  near  to  D.  According  to  other  investigators,  Araki 
and  DiTTRicii,  a  neutral  or  faintly  acid  nietlia;nioglobin  solution  shows 
only  one  characteristic  band  a  between  C  and  Z),  and  the  second  band 
between  D  and  E  is  only  due  to  contamination  Avith  oxyhaemoglobin 
(-Mkxzies).' 

Crystallized  methaemoglobin  may  be  easily  obtained  by  treating  a  con- 
centrated soluton  of  oxylia?moglobin  with  a  sufficient  quantity  of  concen- 
trated potassium  ferriycanide  solution  to  give  the  mixture  a  porter-brown 
color.  After  cooling  to  0°  C.  add  \  vol.  cooled  alcohdl  and  allow  the 
mixture  to  stand  a  few  days  in  the  cold.  The  crystals  may  be  easily  purified 
by  recrystallizing  from  water  by  the  addition  of  alcohol. 

Photometh^emoglobin  is  the  name  given  by  Bock  "  to  a  modification 
of  methnsmoglobin,  produced  under  the  influence  of  sunlight,  which  gives  a 
spectrum  very  simihir  to  haemoglobin. 

Carbon  Monoxide  Haemoglobin '  is  the  molecular  combination  between 
1  mol.  luvmoglobin  and  1  mol.  CO,  according  to  IIufxer,*  which  contains 
1.338  c.c.  carbon  monoxide  (at  0°  and  7G0  mm.  Ilg)  for  1  gm.  haemoglobin. 
This  combination  is  stronger  than  the  oxygen  combination  of  haemoglobin. 
The  oxygen  is  for  this  reason  easily  driven  off  by  carbon  monoxide,  and 
this  explains  the  poisonous  action  of  carbon  monoxide,  which  kills  by  the 
expulsion  of  the  oxygen  of  the  blood. 

Carbon  monoxide  haemoglobin  is  formed  by  saturating  blood  or  a  htemo- 
globin  solution  with  carbon  monoxide,  and  may  be  obtained  as  crystals  by 
the  same  means  as  oxyhaemoglobin.  These  crystals  are  isomorphous  to  the 
oxyhaemoglobin  cr3'stals,  but  are  less  soluble  and  more  stable,  and  their 
blnish-red  color  is  more  marked.  Por  the  detection  of  carbon-monoxide 
hgemoglobiu  its  absorption  spectrum  is  of  the  greatest  importance.  This 
spectrum  shows  two  bands  which  are  very  similar  to  tliose  of  oxyhaemo- 
globin, but  they  occur  more  towards  the  violet  part  of  the  spectrum.  These 
bands  do  not  change  noticeably  on  the  addition  of  reducing  substances; 
this   constitutes   an   important   difference   between  carbon  mgnoxide  and 

'  Jiulerbolm,  1.  c. ;  Bertin-Sans,  Comp.  rend.,  106;  Dittrich,  Arch.  f.  exp.  Path.  u. 
Pharm.,  Bd.  29;  Menzies,  Jouni.  of  Physiol.,  Vol.  17.  Important  references  ou 
metlijemoglobiu  are  given  by  Otto,  Pfluger's  Arch.,  Bd.  31. 

3  Skand.  Arch.  f.  Physiol.,  Bd.  6. 

^  In  reference  to  carbon  mono.xide  hoeiuoglobiu  sec  especially  Hoppe-Seyler,  Med. 
chem.  Untersuch.,  S.  201  ;  Ceutralbl.  f.  d.  med.  "Wissensch.,  1864  and  I860  ;  Zeitschr. 
f.  physiol.  Cheni.,  Bdd.  1  and  13. 

*  Du  Bois-Reymoud's  Archiv,  Physiol.  Abth.,  1894.  On  the  dissociation  constant  of 
carbon  monoxide  haemoglobin,  see  ibid.,  1895. " 


146  .     THE  BLOOD. 

oxyliaenioglobin.  If  the  blood  contains  oxyhaemoglobin  and  carbon-mon- 
oxide haemoglobin  at  the  same  time,  Ave  obtain  on  the  addition  of  a  reducing^ 
substance  (ammouiacal  ferro-tartrate  solution)  a  mixed  spectrum  originating 
from  the  hosmoglobin  and  carbon-monoxide  haemoglobin. 

A  great  many  reactions  have  been  suggested  for  the  detection  of 
carbon-monoxide  haemoglobin  in  medico-legal  cases,  A  simple  and  at  the 
same  time  a  good  one  is  Hoppe-Setler's  soda  test.  The  blood  is  treated 
with  double  its  volume  of  caustic-soda  solution  of  1.3  sp.  gr.,  by  which 
ordinary  blood  is  converted  into  a  dingy  brownish  mass,  which  when 
spread  out  on  jDorcelain  is  brown  with  a  shade  of  green.  Carbon-monoxide 
blood  gives  under  the  same  conditions  a  red  mass,  which  if  spread  out  on 
porcelain  shows  a  beautiful  red  color.  Several  modifications  of  this  test 
have  been  proi^osed. 

As  according  to  Bohr  there  are  several  oxybi3emog]obins,  so  also,  according  to  Bohr 
and  Bock,'  there  an;  several  carbon  monoxide  haemoglobins,  with  different  jimonnts  of 
carbon  monoxide.  As  haemoglobin  can  unite  Avilh  oxygen  and  carbon  dioxide  simul- 
taneousl3^  as  shown  by  Bohr  and  Torup,  so  also  can  it  unite  with  carbon  monoxide  and 
carbon  dioxide  simultaneously  independently  of  each  other. 

Carbon  monoxide  methsemoglobin  has  been  prepared  by  Weil  and  v.  Anrep  by  the 
action  (^  potassium  permanganate  on  carbon  monoxide  hsemoglobin,  but  this  is  con- 
tradicted b}^  Bertin-Sans  and  Moitesbier.'  Sulphur  methsemoglobin  is  the  name 
given  by  Hoppe-Seyler^  to  that  coloring  matter  which  is  formed  by  the  action  of 
sulphuretted  hydrogen  or  oxyhaemoglobin.  Tlie  solution  has  a  greenish-red,  dirty 
color  and  shows  two  absorption-bands  between  C  and  D.  This  coloring  matter  is 
claimed  to  be  the  greenish  color  seen  on  the  surface  ot  putrefying  flesh.  E.  PIarnack"* 
has  investigated  the  action  of  sulphuretted  hydrogen  and  acids  on  the  blood-pigment. 
In  these  investigations  certain  of  Hoppe-Seyler's  statements  in  regard  to  sulphur 
melhaemoglobin  and  the  action  of  the  above  gases  on  the  blood-pigments,  have  been  con- 
firmed. 

Carbon-dioxide  Haemoglobin,  CarholKsmoglobin.  Haemoglobin,  accord- 
ing to  Bohr  and  Torup,*  also  forms  a  molectilar  combination  with  carbon 
dioxide  whose  spectrum  is  similar  to  that  of  ha3moglobin.  According  to 
Bohr  there  are  three  different  carbohaemoglobins,  namely,  a-,  ft-,  and 
^/-carbohaimoglobin,  in  which  1  gm,  combines  with  respectively  1.5,  o,  and 
6  c.c.  CO^  (measured  at  0°  C.  and  760  mm.)  at  +  18°  C.  and  a  pressure  of 
60  mm.  mercury.  If  a  haemoglobin  solution  is  shaken  with  a  mixture  of 
oxygen  and  carbon  dioxide,  the  haemoglobin  combines  loosely  witli  tho 
oxygen  as  well  as  carbon  dioxide,  independently  of  each  other,  just  as  if 
each  gas  existed  alone  (Bohr),  He  considers  that  the  two  gases  are  com- 
bined with  different  parts  of  the  haemoglobin,  namely,  the  oxygen  with  the 
pigment  nucleus   and    the   carbon   dioxide  with  the  proteid   component. 

'  Ceutralbl.  f.  Physiol.,  Bd.  8,  and  Maly's  Jahresber.,  Bd.  25. 

*  V.  Anrep,  Du  Bois-Reymond's  Arch.,  1880;  Stins  and  Moitessier,  Compt.  rend., 
Tome  113. 

2  Med.-chem.  Uutersuch.,  S.  151.     See  Araki,  Zeitschr.  f.  physiol.  Chem.,  Bd.  14. 

♦  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

'  Bohr,  Exlrait  du  Bull  de  I'Acad.  Danoise,  1890.  Centralbl.  f.  Physiol.,  Bd.  4. 
Torup,  Maly's  Jahresber.,  Bd.  17. 


HuEMOCHROMOGEN.  147 

According  to  Torup  the  haBmoglobin  must  therefore  be  ]tartly  decomposed 
by  the  carbon  dioxide  setting  free  some  proteid. 

Nitric-oxide  Haemoglobin  is  also  a  crystalline  niolecnlar  combination 
which  is  even  stronger  than  the  carbon-monoxide  haemoglobin.  Its  solution 
shows  two  absorption-bands  wiiich  are  paler  and  less  sharp  than  the  carbon- 
monoxide  hcvnioglobin  bands,  and  they  do  not  disappear  on  the  addition  of 
reducing  bodies. 

Hopmoglohiii  also  forms  a  molocular  combination  with  acetylene.  Ilydrorynnic  acid 
is  also  claimed  to  form  a  combination  with  hjpmoglobin.  Alethaemoglobin  solutions 
become  of  a  beautiful  red  color  by  tlie  action  of  hydrocyanic  acid,  and,  according  to 
KoBEiiT,'  cyamiiethi£moglobiii  is  probably  formed.  Its  spi-cirum  is  very  similar  to  that  of 
bsemoglobiu,  but  it  is  uot  converted  into  oxylia-moglobin  on  shaking  with  air. 

Decomposition  products  of  the  blood-coloring  matters.  By  its  decomposi- 
tion haemoglobin  yields,  as  above  stated,  a.  proteid,  which  has  been  called 
globin  (Preyer  and  Schulz),  and  a  ferruginous  pigment  as  chief  products. 
The  globin,  which  was  isolated  and  studied  by  Sciiulz'  differs  from  most 
other  proteids  by  containing  a  high  amount  of  carbon,  54.97^,  with  only 
16.89^  nitrogen.  It  is  insoluble  in  water  but  very  easily  soluble  in  acida 
or  alkalies.  It  is  not  dissolved  by  ammonia  in  the  presence  of  ammonium 
chloride.  Nitric  acid  precipitates  it  in  the  cold  but  not  when  warm.  It 
may  be  coagulated  by  heat  but  the  coagulum  is  readily  soluble  in  acids. 
Because  of  these  reactions  it  is  considered  as  a  histon  by  Schulz. 

The  pigment  split  off  is  different,  depending  upon  the  conditions  under 
which  the  cleavage  takes  place. 

If  the  decomposition  takes  place  in  the  absence  of  oxygen,  a  coloring 
matter  is  obtained  which  is  called  by  Hoppe-Setler  hcemochromogen^  by 
other  investigators  (Stokes)  reduced  hcBmatin.  In  the  presence  of  oxygen, 
haemochromogen  is  quickly  oxidized  to  hasmatin,  and  we  therefore  obtaia 
in  this  case  hatnatin  as  a  colored  decomposition  product.  As  haemo- 
chromogen is  easily  converted  by  oxygen  into  htematin,  so  this  latter  may 
be  reconverted  into  hsmochromogen  by  reducing  substances. 

Hsemochromogen  was  discovered  by  Hoppe-Seyler.'  He  was  also  able 
to  obtain  this  coloring  matter  as  crystals.  Hcemochromogen  is,  according 
to  Hoppe-Sey'ler,  the  colored  atomic  group  of  haemoglobin  and  its  com- 
bination with  gases,  and  this  atomic  group  is  combined  with  proteids  in  the 
pigment.  The  characteristic  absorption  of  light  depends  on  the  hwmo- 
chromogen,  and  it  is  also  this  atomic  group  which  binds  in  the  oxyhemo- 
globin 1  mol.  oxygen  and  in  the  carbon-monoxide  haemoglobin  1  mol. 
carbon  monoxide  with  I  atom  iron,  IIoppe-Sey'LER  has  observed  a  com- 
bination between  ha?mochromogen  and  carbon  monoxide,  and  this  combina- 
tion shows  the  spectral  appearance  of  carbon  monoxide  haemoglobin. 

'  Ueber  Cyanmetha-moglobin,  etc.     Stuttgart,  1891. 
»  Zeitschr.  f.  physiol.  Chem.,  Bd.  24. 
«  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 


148  THE  BLOOD. 

An  alkaline  liEemocliromogeu  solution  has  a  beautiful  red  color.  It 
shows  two  absorption-bands,  first  described  by  Stokes,  of  which  the  one  is 
darker  and  lies  between  D  and  E,  and  the  other,  broader  but  not  so  dark, 
covers  the  lines  ^  and  b.  In  acid  solution  hEeniochromogen  shows  four 
bauds,  which,  according  to  Jaderholm,'  depend  on  a  mixture  of  lisemo- 
chromogen  and  hsematoporphyrin  (see  beioAv),  this  last  formed  by  a  partial 
decomposition  resulting  from  the  action  of  the  acid. 

Ilasmochromogen  may  be  obtained  as  crystals  by  the  action  of  caustic 
soda  on  haemoglobin  at  100°  C.  in  the  absence  of  oxygen  (Hoppe-Seyler). 
By  the  decomposition  of  liEemoglobin  by  acids  (of  course  in  the  absence  of 
air)  we  obtain  Wmochromogen  contaminated  with  a  little  hfematoporphyrin. 
An  alkaline  hajmochromogen  solution  is  easily  obtained  by  the  action  of  a 
reducing  substance  (Stokes'  reduction  liquid)  on  an  alkaline  ha^matin 
solution.  Y.  Zeynek''  has  been  able  to  obtain  haemochromogen  in  a  solid 
condition  by  reducing  liaBuiatin  with  hydrazin  hydrate  in  a  faintly 
ammoniacal  solution  under  special  precautions  and  precipitating  the  product 
by  alcohol-etlier.  The  otherwise  pure  and  unchanged  product  seems  to  be 
an  ammonia  combination  of  haemochromogen,  which  is  formed  in  the  reduc- 
tion 6f  the  h^matin  into  htemochromogen  when  for  every  2  molecules  of 
hjematin  only  1  atom  of  oxygen  is  removed  and  the  two  hajmatiu  residues 
are  united  by  1  atom  of  oxygen. 

Haematin,  also  called  Oxyhaematin,  is  sometimes  found  in  old  transuda- 
tions. It  is  formed  by  the  action  of  gastric  or  pancreatic  juices  on 
OX}' haemoglobin,  and  is  therefore  also  found  in  the  faeces  after  hemorrhage 
in  the  intestinal  canal,  and  also  after  a  meat  diet  and  food  rich  in  blood. 
It  is  stated  that  hsematin  may  occur  in  urine  after  poisoning  with  arseniu- 
retted  hydrogen.  As  shown  above,  the  heematin  is  formed  by  the  decom- 
position of  oxyhaemoglobin,  or  at  least  of  haemoglobin,  in  the  presence  of 
oxygen.  Cazekeuve  and  Breteau  '  have  analyzed  haematin  from  different 
kinds  of  blood  (ox,  horse,  sheep)  and  have  found  that  haematin  from  a 
certain  variety  of  blood  has  the  same  composition,  Avhile  that  from  a  differ- 
ent variety  of  animals  has  a  different  composition. 

The  statements  in  regard  to  the  composition  of  haematin  are  rather 
contradictory  which  seems  to  depend  u]oon  the  fact  that  different  ha^matins 
are  formed  under  various  conditions  (Kuster,  K.  Morner).  According 
to  IIoppe-Seyler  its  formula  is  C3 JI^^N^FeO,,  to  Nencki  and  Sieber,  also 
Bialobrzeski  it  is  CjJIjjN.FeO^,  and  according  to  Hufner  and  Kuster, 
probably,  CjJIj.N^FeO^.  The  haematin  analyzed  by  K.  Morner  wliich 
was  not  identical  Avith  ha-matin  j^repared  by  other  investigators,  had  the 
formula,  CjJIjgX^FeOj.  According  to  all  these  investigators  1  atom  of 
iron  occurs  with  every  4  atoms  of  nitrogen.     According  to  Cloetta,  and 

'  Nord.  med.  Arkiv.,  Bd.  16. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  25. 

»  Compt.  rend..  Tome  128. 


n^a MATIN  AND  n.¥.MIN.  149 

also  RosENFELD,"  lia^matin  has  the  formnhi,  C„II,^X,FeO,,  and  1  atom  of 
iron  for  ever}'  3  atoms  of  nitrogen. 

On  ciirefully  oxidizing  hajinatin  (in  glacial  acetic  acid)  with  pnt;i.s.«inm  biclironiate, 
KusTicii  olitainedv  besides  a  forniginous  but  not  closely-studied  body,  two  acids  with  the 
formula',  CjIIioOs  and  C'bIIioOb.  The  first  is  considered  as  bibasic  hiematinic  acid  &ui\ 
the  second  tribasic  lueniatinic  acid. 

IIiBmatin  is  amorphons,  dark  brown  or  bluisli  black.  It  may  be  lieated 
to  180°  C.  without  decomposition;  on  burning  it  leaves  a  residne  consisting 
of  iron  oxide.  It  is  insoluble  in  water,  dilute  acids,  alcohol,  ether,  and 
chloroform,  but  it  dissolves  slighty  in  warm  glacial  acetic  acid.  ILT?matin 
dissolves  in  acidified  alcohol  or  ether.  It  easily  dissolves  in  alkalies,  even 
when  very  dilute.  The  alkaline  solutions  are  dichroitic;  in  thick  layers 
they  appear  red  by  transmitted  light,  and  in  thin  layers  greenish.  The 
alkaline  solutions  are  precipitated  by  lime-  and  baryta-water,  as  also  by 
solutions  of  neutral  salts  of  the  alkaline  earths.  The  acid  solutions  are 
always  brown. 

An  acid  haematin  solution  absorbs  the  red  part  of  the  spectrum  less  and 
the  violet  j-tart  more.  The  solution  shows  a  rather  sharply  defined  band 
between  C  and  D  whose  position  may  change  Avith  the  variety  of  acid  used 
as  a  solvent.  Between  D  and  F  a  second,  much  broader,  less  shar])]y 
defined  band  occnrs  which  by  proper  dilution  of  the  liquid  is  converted  ir.^o 
two  bands.  The  one  between  b  and  F^  lying  near  F^  is  darker  and  broader, 
the  other,  between  D  and  E,  lying  near  2,  is  lighter  and  narrower.  Also 
by  proper  dilution  a  fourth  very  faint  band  is  observed  between  D  and  E 
lying  near  D.  Ilrematin  may  thus  in  acid  solution  show  four  absori)tion 
bands;  ordinarily  one  sees  distinctly  only  the  bands  between  Cand  D  and 
the  broad,  dark  band — or  the  two  bands — between  D  and  F.  In  alkaline 
solution  the  ha3matin  shows  a  broad  absorption-band,  which  lies  in  greatest. 
part  between  0  and  D,  but  reaches  a  little  over  the  line  D  towards  th& 
right  in  the  space  between  D  and  E. 

Haemin,  ILemix  Ckystals,  or  Teichmann's  Crystals.  Hasmin  is  the 
hydrociiloric  acid  ester  of  hwmatin  and  is  the  starting-point  in  the  prei)ara- 
tion  of  the  latter. 

According  to  Nexcki  and  Sieber  the  hpemin  crystals  are  a  double  combination  with 
the  solvent,  amyl  alcohol  or  acetic  acid,  which  is  used  in  tluir  preparation  ;  while 
HoppkSkvlkr  claims  that  the  solvent  is  only  held  mechanically  by  the  crystals.  The 
formula  of  the  luvnun  crystals  prepared  by  means  of  amyl  alcohol  is,  accordiiiir  to 
Nencki  and  Sieber,  (C32H3iClN"4Fe03)«.C6UnO.  Ha^matiu  esters  with  other  acids  are 
also  known  (See  KDster  I.e.). 

'  Hoppe-Seyler,  ^led.  chem.  Untersuch.,  S.  525;  Nencki  and  Sieber,  Arch.  f.  exp. 
Path.  u.  Pharni  ,  Bdd.  18  and  20,  uud  Bar.  d.  dcutsch.  chem.  Gesellsch.,  Bd.  18;  Bial- 
obrzeski.  Arch,  des  scienc.  biol.  de  St.  Petersbourg,  Tome  5  ;  Kilster,  BeitrSge  zur 
Kennfniss  des  Iljcmatins,  Tttbingen,  1896.  and  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd. 
27und30;  K.  Morner,  Nord.  med.  Arkiv.  Festband.,  1897,  No.  1  and  30;  Clo«ta, 
Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  36  ;  Rosenfeld,  ibid.,  Bd.  40. 


150  THE  BLOOD. 

Hamin  crystals  form  in  large  masses  a  blnish-black  powder,  bat  are  so 
Email  that  they  can  only  be  seen  by  the  microsco]3e.  They  consist  of  dark- 
brown  or  nearly  brownish-black  long,  rhombic,  or  spool-like  crystals, 
isolated,  or  gronped  as  crosses,  rosettes,  or  starry  forms.  Cubical  crystals 
may  also  occur  according  to  Cloetta.  They  are  insoluble  in  water,  dilute 
acids  at  the  normal  temperature,  alcohol,  ether,  and  chloroform.  They  are 
slightly  soluble  in  glacial  acetic  acid  with  warmth.  They  dissolve  in 
acidified  alcohol,  as  also  in  dilute  caustic  or  carbonated  alkalies;  and  in  the 
last  case  they  form,  besides  alkali  chlorides,  soluble  hsematin  alkali,  from 
which  the  hsematin  may  be  precipitated  by  an  acid. 

The  principle  of  the  preparation  of  hsemin  crystals  in  large  quantities  is 
as  follows:  The  washed  sediment  from  the  blood-corpuscles  is  coagulated 
with  alcohol  or  by  boiling  after  dilution  with  water  and  the  careful  addition 
of  acid.  The  strongly  pressed  but  not  dry  mass  is  rubbed  with  90-95,^ 
alcohol,  which  has  previously  been  treated  with  oxalic  acid  or  |-1^  con- 
centrated snljDhuric  acid,  i.nd  allow  this  to  stand  several  hours  at  the 
temperature  of  the  room.  The  filtrate  is  warmed  to  about  70°  C,  treated 
with  hvdrochloric  acid  (for  each  liter  of  filtrate  add  10  c.c,  25^  hydro- 
chlori(/acid  diluted  with  alcohol,  Mornee),  and  allow  it  to  stand  in  the 
cold.  The  crystals  which  separate  in  one  or  two  days  are  first  washed  with 
alcohol  and  then  with  water.  For  particulars  as  to  the  various  methods  we 
refer  the  reader  to  the  cited  works  of  Neitcki  and  Sieber,  Cloetta, 
KtJSTER,  MoRNER,  and  Eoseneeld. 

Ilaematin  is  obtained  on  dissolving  the  hsemin  crystals  in  very  dilute 
■caustic  alkali  and  precipitating  with  an  acid. 

In  preparing  h^emin  crystals  in  small  quantities  proceed  in  the  following 
manner:  The  blood  is  dried  after  the  addition  of  a  small  quantity  of 
common  salt,  or  the  dried  blood  may  be  rubbed  with  a  trace  of  common 
salt.  The  dry  powder  is  placed  on  a  microscope-slide,  moistened  with 
glacial  acetic  acid,  and  then  covered  with  the  cover-glass.  x\dd,  by  means 
of  a  glass  rod,  more  glacial  acetic  acid  by  applying  the  drop  at  the  edge  of 
the  cover-glass,  until  the  space  between  the  slide  and  the  cover-glass  is  full. 
Now  warm  over  a  very  small  flame,  with  the  precaution  that  the  acetic  acid 
'does  not  boil  and  pass  with  the  powder  from  under  the  cover-glass.  If  no 
"Crystals  appear  after  the  first  warming  and  cooling,  warm  again,  and  if 
necessary  add  some  more  acetic  acid.  After  cooling,  if  the  experimnt  has 
been  properly  performed,  a  number  of  dark-brown  or  nearly  black  hsemin 
crystals  of  varying  forms  will  be  seen. 

n^ematin  is  dissolved  by  concentrated  sulphuric  acid  in  the  presence  of 
air,  forming  a  purple-red  liquid.  The  iron  is  here  split  off  and  the  new 
pigment,  called  hwrnatoporphyrm  by  Hoppe-Seyler,  is  iron-free.  The 
haematin  yields  with  concentrated  sulphuric  acid,  in  the  absence  of  air, 
a  second  iron-free  coloring  matter  called  hcemaiolin  (IIoppe-Seyler). 
Hsematoporphyrin  may  also  be  prepared  by  the  action  of  glacial  acetic  acid 
saturated  with  hydrobromic  acid  on  haemin  crystals  (Nencki  and  Sieber'). 

'  Hoppe-Seyler,  Med.-chem.  Untersuch.,  S.  52»  ;  Nencki  and  Sieber,  Monatshefte  f. 
Chem.,  Bd.  9. 


ii.EMA  roponrii  thin.  1 51 

Hsematoporphyrin,  C',,]r,,N,0,.  This  pigment,  according  to  Mac 
MuNN,'  occurs  as  a  physiological  pigment  in  certain  animals.  It  occurs, 
as  shown  by  Gauuod  and  Saillkt,  as  a  normal  constituent,  altliongh  only 
as  traces,  of  Kuman  urine.  It  occurs  in  greater  quantities  in  human  urine 
especially  after  the  use  of  sulphonal  (see  Chapter  XV). 

This  coloring  matter  is,  according  to  Nencki  and  Sieber,  an  isomer  of 
the  bile-pigment  bilirubin,  and  its  formation  from  haimatiu  can  be  expressed 
by  the  following  equation: 

C.JI^N.O.Fe  +  2H,0  -  Fe  -  2C,.II„N,0,. 

A  pigment  closely  allied  to  the  urinary  pigment  urobilin  has  been  obtained 
by  the  action  of  reducing  substances  on  haemotoporphyrin  (IIoppe-Seyler, 
Nencki  and  Sieber,  Le  Nobel,  Mac  Munn).  On  the  administration  of 
haemotoporphyrin  to  rabbits,  Nencki  and  Kotschy'  observed  that  a  part 
■was  reduced  to  a  substance  similar  to  urobilin. 

On  heating  ha^matoporphyrin  it  decomposes  and  evolves  an  odor  of 
pyrrol.  It  dissolves  with  a  red  color  in  warm,  fuming  nitric  acid,  and  the 
solution  becomes  then  green,  blue,  and  yellow.  The  hydrochloric  acid 
combination  crystallizes  in  long  brownish-red  needles.  If  the  solution  in 
hydrochloric  acid  is  nearly  neutralized  and  then  treated  with  sodium  acetate, 
the  pigment  separates  out  as  amorphous,  brown  flakes  not  readily  soluble  in 
amyl  alcohol,  ether,  and  chloroform,  but  readily  soluble  in  ethyl  alcohol, 
alkalies,  and  dilute  mineral  acids.  The  combination  with  sodium  crystal- 
lizes as  small  tufts  of  brown  crystals.  The  acid  alcoholic  solutions  have  a 
beautiful  purple  color,  which  becomes  violet-blue  on  the  addition  of  large 
quantities  of  acid.  The  alkaline  solution  has  a  beautiful  red  color, 
especially  when  not  too  much  alkali  is  i)resent.  Ilaimatoporphyrin  j^repared 
by  various  methods  may  differ  somewhat  in  solubility  and  in  color  of  solu- 
tion, but  their  characteristic  absorption-sjiectra  are  essentially  the  same. 

An  alcoholic  solution  of  hsematoporphyrin,  acidulated  with  hydrochloric 
or  sulphuric  acid,  shows  two  absorption-bands,  of  which  one  is  fainter  and 
narrower  and  lies  between  C  and  Z>,  near  D.  The  other  is  much  darker, 
sharper  and  broader,  and  lies  in  the  middle  between  D  and  E.  An  absorp- 
tion extends  from  these  bands  towards  the  red,  terminating  vrith  a  dark 
edge,  which  may  be  considered  as  a  third  baud  between  the  other  two. 

A  dilute  alkaline  solution  shows  four  bands,  namely,  a  band  between  C 
and  D;  a  second,  broader,  surrounding  D  and  with  its  broadest  part 
between  D  and  E\  a  third,  between  D  and  E  nearly  at  E\  and  lastly  a 
fourth,   broad  and  dark  band  between  b  and   F.     On  the  addition  of  an 

'  Journ.  of  Physiol.,  "Vol.  7. 

»  Hoppe-Soyler,  1.  c.  S.  523  ;  Le  Nobel,  Pfliiger's  Arch.,  Bd.  40  ;  Mac  Munii,  Proc. 
Roy.  Soc,  Vol.  30,  aud  Joura.  of  Physiol.,  Vol.  10;  Nencki  uud  liotachy,  Moualshefte 
f.  Chem.,Bd.  10. 


152  THE  BLOOD. 

alkaline  zinc-chloride  solution  the  spectrum  changes  more  or  less  rapidly/ 
and  finally  a  spectrum  is  obtained  with  only  two  bands,  of  which  one  sur- 
rounds D  and  the  other  lies  between  D  and  E.  If  an  acid  haematoporphyrin 
solution  is  shaken  with  chloroform,  a  part  of  the  pigment  is  taken  up  by 
the  chloroform,  and  this  solution  often  shows  a  five-banded  spectrum  with 
two  bands  between  C  and  D. 

Hsematoidin,  thus  called  by  Virchow,  is  a  pigment  which  crystallizes 
in  orange-colored  rhombic  plates,  and  which  occurs  in  old  blood  extravasa- 
tions, and  whose  origin  from  the  blood-coloring  matters  seems  to  be  estab- 
lished (Langhans,  Coedua,  Quincke,  and  others').  A  solution  of 
hffimatoidin.  shows  no  absorption-bands,  but  only  a  strong  absorption  of  the 
violet  to  the  green  (Ewald^).  According  to  most  observers,  hsematoidin 
is  identical  with  the  bile-pigment  bilirubin.  It  is  not  identical  with  the 
crystallizable  lutein  from  the  corpora  lutea  of  the  ovaries  of  the  cow  (Picco- 
lo and  LiEBEX,'  Kuhne  and  Ewald). 

In  the  detection  of  the  above-described  blood-coloring  matters  the- 
spectroscope  is  the  only  entirely  trustworthy  means  of  investigation.  If  it 
is  only  necessary  to  detect  blood  in  general  and  not  to  determine  definitely 
whether  the  coloring  matter  is  hgemoglobin,  methasmoglobin,  or  h^ematin, 
then  the  preparation  of  heemin  crystals  is  an  absolute  positive  proof.  The 
reader  is  referred  to  more  extended  text-books  for  exacter  methods  for  the 
detection  of  blood  in  chemico-legal  cases,  and  it  is  perhaps  sufficient  to  give 
here  the  chief  points  of  the  investigation. 

If  spots  on  clothes,  linen,  wood,  etc.,  are  to  be  tested  for  the  presence 
of  blood,  it  is  best,  when  possible,  to  scratch  or  shave  off  as  much  as 
possible,  rub  with  common  salt,  and  from  this  prepare  the  hfemin  crystals. 
On  obtaining  positive  results  the  presence  of  blood  is  not  to  be  doubted. 
If  yon  do  not  obtain  sufficient  material  by  the  above  means,  then  soak  the 
spot  with  a  few  drops  of  water  in  a  watch-crystal.  If  a  colored  solution  is 
thus  obtained,  then  remove  the  fibres,  wood-shavings,  and  the  like  as  far  as. 
possible,  and  allow  the  solution  to  dry  in  the  watch-glass.  The  dried 
residue  may  be  partly  used  for  the  spectroscope  test  directly,  and  part  may 
be  employed  in  the  preparation  of  the  hfemin  crystals.  It  also  serves  to 
detect  hEemochromogen  in  alkaline  solution  after  previous  treatment  with 
alkali  and  the  addition  of  reducing  substances. 

If  a  colorless  solution  is  obtained  after  soaking  with  water,  or  the  spots 
are  on  rusty  iron,  then  digest  with  a  little  dilute  alkali  (5  p.  m.).  In  the 
presence  of  blood  the  solution  gives,  after  neutralization  with  hydrochloric 
acid  and  drying,  a  residue  which  may  give  the  haemin  crystals  with  glacial 
acetic  acid.     Another  part  of  the  alkaline  solution  shows,  after  the  addition 


'  See  Hammarsteu,  Skaiul.  Arch.  f.  Physiol.,  Bd.  3,  aud  Garrod,  Journ.  of  Pliysiol. 
Vol.  13. 

'  A  comprehensive  review  of  the  literature  pertaining  to  hoematoidin  may  be  found 
in  Stttdelmanu:  Der  Icterus,  etc.     Stuttgart,  1891.     Pages  3  and  45. 

3  Zeitschr.  f.  Biologie,  Bd.  22,  S.  475. 

*  Cit.  from  Gorup-Besanez:  Lebrbuch  d.  phy.siol.  Cbem.,  4.  Aufl.,  1878. 


SrECTROPITO  TO M ETUI C  Es TIMA  TION.  1  ."iS 

of  Stokks'   reduction  li(iuid,   the  absorption-bands  of  liivmochromogen  in 
alkaline  solution. 

The  methods  proposed  for  the  quantitative  estimation  of  tlie  Ijlood- 
coloring  mattecs  are  partly  chemical  and  partly  physical. 

Among  the  chctniciil  iiiothotls  to  be  mentioned  is  tlie  asliing  of  llic  blood  and  tlie 
dt'teiniiniition  of  the  amount  of  iron  contained  therein,  from  which  the  amount  of 
hiemoglobin  may  be  calculated.  Jollkb  '  has  recently  suggested  a  clinical  method  based 
on  the  incineratio'.i  of  the  blood  and  determining  the  iron  in  the  ash. 

The  physical  methods  consist  either  in  a  colorimetric  or  a  spectroscopic 
investigation. 

The  principle  of  IIoppe-Seyler's  colorimetric  method  is  that  a  measured 
quantity  of  blood  is  diluted  with  an  exactly  measured  quantity  of  water 
until  the  diluted  blood  solution  has  the  same  color  as  a  pure  oxyha?moglobin 
solution  of  a  known  strength.  The  amount  of  coloring  matter  present  in 
the  nndiltited  blood  may  be  easily  calculated  from  the  degree  of  dilution. 
In  the  colorimetric  testing  we  use  a  glass  vessel  with  parallel  sides  contain- 
ing a  layer  of  liquid  1  cm.  thick  (1Iopi'E-Seyler\s  h;vmatinometer). 
The  use  of  IIoppe-seyler's  colorimetric  double  pipette  is  more  advan- 
tageous. Other  good  apparatus  have  been  constructed  by  Giacosa  and 
Zancjermeistek."  Instead  of  an  oxyhemoglobin  solution  we  now  gen- 
erally use  a  carbon  monoxide  hemoglobin  solution  as  comparison  liquid 
because  it  may  be  kept  for  a  long  time. 

The  blood  solution  in  this  case  is  saturated  with  carbon  monoxide. 
This  method  seems  to  be  good. 

The  quantitative  estimation  of  the  blood-coloring  matters  by  means  of 
the  spectroscope  may  be  done  in  different  ways,  but  at  the  present  time  the 
S})ectrophotomctric  method  is  chiefly  nsed,  and  this  seems  to  be  the  most 
reliable.  This  method  is  based  on  the  fact  that  the  extinction  coefficient 
of  a  colored  liquid  for  a  certain  region  of  the  spectrum  is  directly  propor- 
tional to  the  concentration,  so  that  C :  E  =  C\  :-£",,  when  ('  and  C\  repre- 
sent the  different  concentrations  and  E  and  E^  the  correspondinE:  coefficients 

C       C 
of  extinction.     From  the  equation  —  =  ~  it  follows  that  for  one  and  the 

E       E^ 

same  pigment  this  relation,  which  is  called  the  absorption  ratio,  must  be 

constant.     If  the  absorption  ratio  is   represented  by  .1,   the  determined 

extinction  coefficient  by  E,  and  the  concentration  (the  amount  of  coloring 

matter  in  grams  in  1  c.c.)  by  (7,  then  C  =  A  .  E. 

Different  apparatus  have  been  constructed  (Vierordt  and  Hufner') 

for  the  determination  of  the  extinction  coefficient  which  is  equal   to  the 

negative  logarithm  of  those  rays  of  light  which  remain  after  the  passage  of 

the  liglit  through  a  layer  1  cm.  thick  of  an  absorbing  liquid.     In  regard  to 

these  a[)paratus  the  reader  is  referred  to  other  text-books. 

'  Pflliger's  Arch.,  Bd.  65,  and  Monatshefte  f.  Chem.,  Bd.  17. 

*  F.  Iloppe-Seyler,  Zeitschr.  f.  physiol.  Chem.,  Bd.  16  ;  G.  Iloppe-Seyler,  ibid.,  Bd. 
21  ;  Wiuternilz,  ibid.;  Giacosa,  Maly's  Jahresber.,  Bd.  26;  Zangenmeister,  Zeitschr.  f. 
Biologic,  Bd.  33. 

^  See  Vierordt,  Die  Anwendung  des  Spektralapparates  zu  Photometric,  etc.  (Tubin- 
gen, 1873),  and  Hufner,  Du  Bois-Reymond's  Arch.,  1894,  and  Zeitschr.  f.  physiol.  Chem., 
Bd.  3  ;  V.  Noorden,  ibid.,  Bd.  4  ;  Otto,  Ptliiger's  Arch.,  Bdd.31  and  36. 


154  THE  BLOOD. 

As  control  the  extinction  coefficients  are  determined  in  two  different  regions  of  the 
spectrum.  Ht^fner  has  selected  (a)  the  region  between  the  two  absorption  bands  of 
oxyhaemoglobin,  especially  between  the  wave-lengths  554  j.i  and  565  /.t,  and  {h)  the 
region  between  the  two  bands,  especially  the  interval  between  the  wave-lengths  531.5  /.i 
Vi\u\  542.5  i-i.  The  constants  or  the  absorption  ratio  for  these  two  regions  of  the  spec- 
Inim  are  designated  by  Hufner  by  A  and  A'.  Before  the  determination  ihe  blood  must 
be  diluted  with  water,  and  if  the  proportion  of  dilution  of  the  blood  be  represented  by 
V,  then  the  concentration  or  the  amount  of  coloring  matter  in  100  parts  of  the  undiluted 
blood  is 

C=lQO.V.  A.  E  and 

C  =  100  .  V.  A'.  E'. 

The  absorption  ratio  or  the  constants  in  the  two  above-mentioned  regions  of  the 
spectrum  have  been  determined  for  oxyhaemoglobin,  haemoglobin,  carbon  monoxide,  as 
follows  : 

Oxyhfemoglobin Ao  =  0.002070  and  A'o  =  0.001312 

Haemoglobin Ar  =  0.001354  and  A'r  =  0.001778 

Carbon-monoxide  haemoglobin  Ac  =  0.001383  and  A'c  =  0.001263 

The  quantity  of  each  coloring  matter  may  be  determined  in  a  mixture  of  two  blood- 
coloring  matters  by  this  method,  which  is  of  special  importance  in  the  determination  of 
the  quantity  of  oxyhaemoglobin  and  haemoglobin  present  in  blood  at  the  same  time.  If 
w(j  represent  by  ^'and  E'  the  extinction  coefficients  of  the  mixture  in  the  above-men- 
tioned regions  of  the  spectrum,  by  Joand  J.'o  aud^r-aud  A'r  the  constants  for  oxyhaemo- 
globin and  reduced  haemoglobin,  and  by  Fthe  degree  of  dilution  of  the  blood,  then  the 
percentage  of  oxyhaemoglobin  Ho  and  of  (reduced)  haemoglobin  Hr  is 


Ho  =  100  .  V. 
and 

Hr  =  100  .  F, 


ApA'oiEAr  -  E'A'r) 

A  A'rjE'A'o  -EAo) 

Ji.  oAr  —  Ao-A  r' 


Among  the  many  apparatus  constructed  for  clinical  purposes  for  the 
quantitative  estimation  of  haemoglobin  Fleischl's  hmmometer,  which  has 
undergone  numerous  modifications,  and  Hexocque's  limmatoscope  are  to  be 
specially  mentioned.  In  regard  to  these  apparat^  see  v.  Jaksch,  Klinische 
IJiagnostik  innerer  Krankheiten,  4.  Auflage  18  and  Jaquet,  Corresp. 
lilatt.  f.  Schweiz.  Aerzte,  1897. 

Many  otlier  pigments  are  found  besides  the  often-occurring  haemoglobin  in  the  blood 
of  invertebrates.  In  a  few  arachnidae,  crusiacea,  gasteropodae,  and  cephalopodae  a  body 
analogous  to  haemoglobin  containing  copper,  hamocyanin.  has  been  found  by  Fredericq. 
By  the  taking  up  of  loosely  bound  oxygen  this  body  is  converted  into  blue  oxylnnno- 
cynniii,  and  by  the  escape  of  the  oxygen  becomes  colorless  again.  A  coloring  matter 
called  chlorocruorin  hy  Lankebteu  is  found  in  certain  clia-topodae.  Hfmerythrin,  so 
called  by  Kkl-kenbehg  but  first  observed  by  Schwalbe,  is  a  red  coloring  matter  from 
certain  irephyrea.  Besides  ha'mocyanin  we  find  in  the  blood  of  certain  Crustacea 
tlie  red  coloring  matter  <«<?-on(?r?/</t7'm  (Halliburton),  which  is  also  widely  spread  in 
tlie  animal  kingdom.  Echinochrom,  so  named  by  Mac  Munn,'  is  a  brown  coloring 
matter  occurring  in  the  perivisceral  fluid  of  a  variety  of  ecliinoderms. 

The  quantitative  constitution  of  the  red  hlood-corpusdes.  The  amount 
of  water  varies  in  different  varieties  of  blood  betAveen  570-644  p.  m.,  with 
a  corresponding  amount,  430-350  p.  m.,  of  solids.     The  chief  mass,  about 

'  Fredericq,  Extrait  des  Bulletins  de  I'Acad.  Roy.  de  Belgique  (2),  Tome  46,  1878  ; 
Lankester,  Journ.  of  Anat.  and  Physiol.,  1868,  p.  114,  and  1870,  p.  119;  Krukenberg, 
see  Vergl.  Physiol.  Studien,  Reilie  1,  Abth.  3.  Heidelberg,  1880  ;  Halliburton,  Journal 
of  Physiol.,  Vol  6  ;  Mac  Munn,  Quart.  Journ.  31icrosc.  Science,  1885. 


COMPOSITION  OF  THE  RED-CORPUSCLES.]  166 

Y^j— !»£,,    of    the    dried    substance  consists    of    haemoglobin   (in   human    and 
mammal  blood). 

According  to  the  analyses  of  Hoppe-Seyler  '  and  his  pupils,  the  red 
corpuscles  contain  in  1000  parts  of  the  dried  substance: 

Haemoglobin.  Proteid.  Lecithin.  Cholesterin. 

Human  blood 868-943  122-51  7.2-3.5            2.5 

Dog's          "     865  126                 5.9               3.6 

Goose's       "     627  364                 4.6               4.8 

Snake's       "     467  525 

Abdekiialden  found  the  following  composition  for  the  blood-corpuscles 
from  the  domestic  animals  investigated  by  him:  Water,  591.9-644.3 
p.  m. ;  solids,  408.1-355.7  p.  m. ;  ha3moglobin,  303.3-331.9  p.  m.;  proteid, 
5.32  (dog)-T8.5  p.  m.  (sheep);  cholesterin,  0.388  (liorse)-3.593  p.  m. 
(sheep);  and  lecithin,  2.296  (dog)-4.855  p.  m. 

Of  special  interest  is  the  varying  proportion  of  the  luemoglobin  to  the 
proteid  in  the  nucleated  and  in  the  non-nucleated  blood-corpuscles.  These 
last  are  much  richer  in  haemoglobin  and  poorer  in  proteid  than  the  others. 

The  amount  of  mineral  bodies  in  various  varieties  of  animals  is  different. 
According  to  Buxge  and  ABDEunALDEN  the  red  corpuscles  from  the  pig, 
horse,  and  rabbit  contain  no  soda,  while  those  from  man,  the  ox,  sheep,  goat, 
dog,  and  cat  are  relatively  rich  in  soda.  In  the  five  last-mentioned  varieties 
the  amount  of  soda  was  2.135-2.856  p.  m.  The  quantity  of  potash  was 
0.257(dog)-0.744  p.  m.  (sheep).  In  the  horse,  pig,  and  rabbit  the  quantity 
of  potash  was  3.326  (horse)-5.229  p.  m.  (I'ubbit).  Human  blood-corpuscles 
contain,  according  to  Wanach,'  about  five  times  as  much  potash  as  soda, 
on  an  average  3.99  p.  m.  potash  and  0.75  p.  m.  soda.  Lime  is  claimed  to 
be  absent  in  the  blood-corpuscles,  and  magnesia  occurs  only  in  small 
amounts,  0.016  (sheep)-0.150  p.  m.  (pig).  The  blood-corpuscles  of  all 
animals  investigated  contain  chlorine,  0.460-1.940  p.  m.  (both  in  horse), 
generally  1  to  2  p.  m.,  and  also  phosphoric  acid.  The  amount  of  inorganic 
phosphoric  acid  shows  great  variation,  0.275  (sheep)-1.916  p.  m.  (horse). 
All  above  figures  are  calculated  on  the  fresh,  moist  blood-corpuscles. 

The  White  Blood-corpuscles  and  the  Blood-plates. 

The  White  Blood-corpuscles,  also  called  Leucocytes  or  Lymphoid 
Cells,  which  occur  in  the  blood  in  varying  forms  and  sizes,  form  in  a  state 
of  rest  spherical  lumps  of  a  sticky,  highly  refractive  power,  capable  of 
motion,  non-membranous  protoplasm,  which  show  1-4  nuclei  on  the  addi- 
tion of  water  or  acetic  acid.  In  human  and  mammalian  blood  they  are 
larger  than  the  red  blood-corpuscles.      They  have   also  a   lower  specific 

»  Med.-cheiu.  Untersuch.,  S.  390  and  393. 

*  Buuge,  Zeitschr.  f.  Biologic,  Bd.  12,  and  Abderhaldeu,  Zeitschr.  f.  physiol.  Chem., 
Bdd.  23  and  25  ;  Wanach,  Maly's  Jahresber.,  Bd.  18,  S.  88. 


15G  THE  BLOOD. 

gravity  than  the  red  corpuscles,  move  in  the  circulating  blood  nearer  to  the 
■walls  of  the  vessel,  and  have  also  a  slower  motion. 

The  number  of  white  blood-corpuscles  varies  not  only  in  the  different 
blood-vessels,  but  also  under  different  physiological  conditions.  As  an 
average  we  have  only  1  white  corpuscle  for  350-500  red  corpuscles. 
According  to  the  investigations  of  Alex.  Schmidt  '  and  his  pupils,  the 
leucocytes  are  destroyed  in  great  part  on  the  discharge  of  the  blood  before 
and  during  coagulation,  so  that  discharged  blood  is  much  poorer  in  leuco- 
cytes than  the  circulating  blood.  The  correctness  of  this  statement  has 
been  denied  by  other  investigators. 

From  a  histological  standpoint  we  generally  discriminate  between  the 
different  kinds  of  colorless  blood-corpuscles;  chemically  considered,  how- 
ever, there  is  no  known  essential  difference  between  them.  With  regard  to 
their  importance  in  the  coagulation  of  fibrin  Alex.  Schmidt  and  his  pupils 
distinguish  between  the  leacocytes  which  are  destroyed  by  the  coagulation 
and  those  which  are  not.  The  last  mentioned  give  with  alkalies  or 
common-salt  solutions  a  slimy  mass;  the  first  do  not  show  such  behavior. 

The  protoplasm  of  the  leacocytes  has  daring  life  amoeboid  movements 
which  partly  make  possible  the  wandering  of  the  cells  and  partly  the  taking 
up  of  smaller  grains  or  foreign  bodies  within  the  same.  On  these  grounds 
the  occurrence  of  myosin  in  them  has  been  admitted  even  without  any 
special  proof  thereof.  Alex.  Schmidt  claims  to  have  found  serglohulin  in 
equine-blood  leucocytes  which  had  been  washed  with  ice-cold  water.  There  ^ 
are  also  certain  leucocytes,  as  above  stated,  which  yield  a  slimy  mass  when 
treated  with  alkalies  or  NaCl  solutions,  which  seem  to  be  identical  with  the 
so-called  hyaline  siibstance  of  Eoyida  found  in  the  pus-cells.  On  digesting 
the  leucocytes  with  water  a  solution  of  a  protein  body  is  obtained  which  can 
be  precipitated  by  acetic  acid  and  forms  the  chief  mass  of  the  leacocytes. 
This  substance,  which  is  undoubtedly  related  to  coagulation,  has  been, 
described  under  different  names  (see  Chapter  Y),  and  consists,  chiefly  at 
least,  of  nucleohiston. 

Glycogen,  as  above  stated  (Chapter  V),  is  found  in  the  leucocytes.  The 
glycogen  found  by  IIuppert,  Czerny,  Dastre,^  and  others  in  blood  and 
lymph  probably  originated  from  the  leucocytes.  The  constituents  of  the 
leucocytes  are  the  same  as  the  constituents  of  the  cell  as  described  in 
Chapter  V. 

The  blood-plates  (Bizzozero's),  hsematoblasts  (Hayem),  whose  nature 
and  physiological  importance  have  been  much  questioned,  are  pale,  color- 
less,  gummy   disks,    round   or  more  oval   in   shape  and  generally  with  a 

'  Pfluger's  Archiv,  Bd.  11. 

»  H\ippert,  Centralbl.  f.  Physiol.,  Bd.  6,  S.  394;  Czerny,  Arch.Tf.  exp.  Path.  u. 
Pharm.,  Bd.  31 ;  Dastre,  Compt.  rend.,  Tome  120,  and  Arch  de  Physiol.  (5),  Tome  7. 


PliOPERTIES  OF  BLOOD.  157 

diameter  two  or  three  times  smaller  tliiui  the  red  blood-corpascles.  'J'lie 
"blood-plates  separate  ino  two  substances  by  the  action  of  dilTereiit  reagents, 
namely,  one  which  is  homogeneous  and  non-refractive,  wliile  the  other  is 
highly  refractive  and  granular.  Blood-plates  readily  stick  together  and 
attach  tliemselves  to  foreign  bodies. 

According  to  tlie  important  researches  of  Kossel  and  Lilienfeld  the 
l)lood-plates  consist  of  a  chemical  combination  between  proteid  and  nuclein, 
and  hence  they  are  also  called  nudein-plates  by  Lilienfeld.  It  seems 
certain  that  the  blood-plates  stand  in  a  certain  relationship  to  the  coagula- 
tion of  blood,  and  according  to  Lilienfeld  the  fibrin  coagulation  is  indeed 
a  function  of  the  cell  nucleus.  The  importance  of  these  formations  to 
blood  coagulation  will  be  referred  to  later. 


Ill,  The  Blood  as  a  Mixture  of  Plasma  and  Blood- 
corpuscles. 

The  blood  in  itself  is  a  thick,  sticky,  lighter  or  darker  red  opaque  liquid 
having  a  salty  taste  and  a  faint  odor  differing  in  different  kinds  of  animals. 
On  the  addition  of  sulphuric  acid  to  the  blood  the  odor  is  more  pronounced. 
In  adult  human  beings  the  specific  gravity  ranges  between  l.Oio  and  1.075. 
It  has  an  average  of  1.058  for  grown  men  and  a  little  less  for  women. 
According  to  Sgherkenziss  '  the  foetal  blood  has  a  lower  specific  gravity 
than  the  blood  of  grown  persons.  Lloyd  Jones  found  that  the  specific 
gravity  is  highest  at  birth  and  lowest  in  children  when  about  two  years  old 
and  in  pregnant  women.  The  determinations  of  Lloyd  Jones,  IIammek- 
SCHLAG,^  and  others  show  that  the  variation  of  the  specific  gravity, 
dependent  upon  age  and  sex,  corresponds  to  the  variation  in  the  quantity  of 
haemoglobin. 

The  determination  of  the  specific  gravity  is  most  accurately  done  by 
means  of  the  pyknometer.  For  clinical  purposes  where  only  small  amounts 
are  available  it  is  best  to  proceed  with  the  method  as  suggested  by 
Hammerschlag.'  Prepare  a  mixture  of  chloroform  and  benzol  of  about 
1.050  sp.  gr.  and  add  a  drop  of  the  blood  to  this  mixture.  If  the  drop 
rises  to  the  surface  then  add  benzol,  and  if  it  sinks  add  chloroform.  Con- 
tinue this  until  the  drop  of  blood  suspends  itself  midway  and  then  determine 
the  specific  gravity  of  the  mixture  by  means  of  an  areometer.     This  method 

'  In  regard  to  the  literature  of  the  blood-plates,  see  Lilienfeld,  Du  Bols-Reymond's 
Archiv,  1892,  and  'Leukocytcn  uud  Blutgerinnung,"  Verhandl.  d.  physiol.  Gesollsch. 
zu  Berlin,  1892  ;  iind  also  Moseu,  Du  Bois-Reymond's  Arch.,  1893. 

'Lloyd  Jones,  Journ.  of  Physiol.,  Vol.  8;  Hainmerschlag,  Wieu.  klin.  Wochen- 
fichrift,  1890,  and  Zeitschr.  f.  klin.  med.,  Bd.  20. 

'  1.  c. 


158  THE  BLOOD. 

is  not  strictly  accurate  and  must  be  performed  quickly.     In  regard  to  the 
necessary  details  we  refer  to  Zuntz,' 

The  reaction  of  the  blood  is  alkaline.  The  quantity  of  alkali,  calculated 
as  NajCO,,  in  fresh,  non-defibrinated  blood  from  the  dog,  horse,  and  man 
is,  according  to  Loewt,  4,93,  4.43,  and  5.95  p.  m.  respectively.  According 
to  Strauss,  the  average  for  normal  hnman  blood  may  be  calculated  as 
about  4.43  p.  m.  Xa^COj.  Below  3.3  p.  m.  and  above  5.3  p.  m.  are, 
according  to  him,  to  be  considered  as  pathological,  y.  Jaksch  found  the 
quantity  of  alkali  in  man  to  vary  between  3.38  and  3.90  p.  m.  "The 
alkaline  reaction  diminishes  outside  of  the  body,  and  indeed  the  more 
quickly  the  greater  the  original  alkalinity  of  tlie  blood.  This  depends  on 
the  formation  of  acid  in  the  blood,  in  which  the  red  blood-corpuscles  seem 
to  take  part  in  some  way  or  another.  After  excessive  muscular  activity  the 
alkalinity  is  diminished  on  account  of  the  formation  of  acid  in  the  muscles 
(Peiper,  Cohxsteix),  and  it  is  also  decreased  after  the  continuous  use  of 
acids  (Lassar,  Freudberg  ').  We  have  numerous  investigations  in  regard 
to  the  alkalinity  of  the  blood  in  disease,  but  as  we  have  at  preseut  no  trust- 
worthy method  for  estimating  the  alkalinity  of  the  blood,  these  investiga- 
tions, as  also  the  statements  in  regard  to  the  physiological  alkalinity,  require 
further  substantiation.'  Spiro  and  Pemsel^  have  suggested  a  method  cf 
determining  the  native  alkalinity  of  the  blood  which  consists  in  treating  the 
blood  with  ether-water  (water  saturated  with  ether),  next  precipitating  all 
the  protein  substances  by  neutral  ammonium  sulphate,  and  then  titrating 

the  filtrate  with  —  acid,  using  the  indicator  (lacmoid  and  malachite  green) 

in  the  manner  suggested  by  Forster. 

The  alkali  of  the  blood  exists  in  part  as  alkaline  salts,  carbonate  and 
phosphate,  and  part  in  combination  with  proteid  or  haemoglobin.  The  first 
are  often  spoken  of  as  readily  diffusible  alkalies,  while  the  others  are  not,  or 
are  only  diffusible  with  difficulty  (see  page  135).  The  readily  as  well  as 
the  difficultly  diffusible  alkali  is  divided  between  the  blood-corpuscles  and 
plasma,  and  the  blood-corpuscles  seem  to  be  richer  in  difficultly  diffusible 
alkali  than  the  plasma  or  serum.     This  division  may  be  changed  by  the 

'  PflQger's  Arch.,  Bd.  66. 

*  Loewy,  Pfliiger's  Arch.,  Bd.  58,  which  also  contains  the  references  to  the  literature; 
H.  Strauss,  Zeitschr.  f.  klin.  Med.,  Bd.  30  ;  v.  Jaksch,  ibid.,  Bd.  13;  Peiper,  Virchow's 
Arch.,  Bd.  116;  Cohnstein,  ibid.,  Bd.  130,  which  also  cites  the  works  of  Minkowski, 
TaMhV/.,  and  Geppert ;  Freudberg,  ibid.,  Bd.  125. 

'  In  regard  to  the  methods  for  the  estimation  of  the  alkalinity  see,  besides  the  above- 
mentioned  authors,  v.  Jaksch.  Klin.  Diaguo.stik;  v.  Limbeck,  \Vien.  med.  BliUter,  Bd. 
18  ;  Wright,  Tiio  Lancet,  1897 ;  Biernacki,  Beitriige  zur  Pneumatologie,  etc.,  Zeitschr. 
f.  klin.  Med.,  Bdd.  31  and  32  ;  Hamburger,  Eine  Methode  zur  Trenuung,  etc.,  Du  Boia- 
Reymond's  Arch.,  1898. 

*  Zeitschr.  f.  physiol.  Chem..  Bd.  26. 


ISOTONISM.  159> 

influence  of  even  very  small  amounts  of  acid,  also  carbon  dioxide,  and  also, 
as  shown  by  Zuntz,  Loewy  and  Zuxtz,  IIamhukgku,  LiMUErK  and 
GuRBEU,'  by  the  influence  of  the  respiratory  exchange  of  gjis.  The  blood- 
corpuscles  give  w\i.•^.  part  of  the  alkali  united  with  proteid  to  the  serum  by 
the  action  of  carbon  dioxide,  hence  the  serum  becomes  more  alkaline.  The 
equilibrium  of  the  osmotic  tension  in  the  blood-corpuscles  and  in  the  serum 
is  hereby  destroyed;  the  blood-corpuscles  swell  up  because  they  take  up 
water  from  the  serum  and  this  then  becomes  more  concentrated  and  richer 
in  alkali,  proteid,  and  sugar.  Under  the  influence  of  oxygen  the  corpuscles 
take  their  oriijinal  form  again  and  the  above  changes  are  restored.  The 
blood-corpuscles  for  this  reason  are  less  biconcave  with  a  small  diameter  in 
renous  than  in  arterial  blood  (Hamburger). 

The  volume  of  the  blood-corpuscles  changes  also  with  the  composition 
i)f  the  medium  surrounding  them.  The  volume  remains  unchanged  only 
in  those  indifferent  solutions  which  have  the  same  osmotic  tension,  such  as 
the  plasma  or  serum.  Such  solutions  are  called  isotonic.  In  less  concen- 
trated solutions,  so-called  hi/pisotonic  solutions,  the  blood-corpuscles  swell 
up,  taking  up  water  at  the  same  time,  until  the  osmotic  equilibrium  has 
been  established  again  and  the  volume  becomes  greater.  In  solution  of 
greater  concentration,  liyperisotonic  solutions,  they  give  uj)  water  and  their 
volume  becomes  smaller.  A  NaCl  solution  of  about  9  p.  m.  seems  to  be 
isotonic  with  most  of  the  varieties  of  blood  investigated,  namely,  human, 
ox,  and  horse  blood,  but  even  in  such  solutions  an  exchange  may  take  place 
between  the  constituents  of  the  blood -corpuscles  and  the  solution  (IIedin  '). 
Hamburger  '  has  shown  by  continued  investigations  on  the  action  of  salt 
solutions  on  the  volume  of  animal  cells  that  not  only  are  the  red  corjiuscles 
shrunk  up  by  a  hyperisotonic  solution,  and  swell  up  by  a  hypisotonic  solution, 
but  also  the  white  corpuscles  and  frog  spermatozoa.  The  extent  of  this  swell- 
ing and  shrinkage  is  much  smaller  than  if  the  cell  was  a  homogeneous  mass, 
which  leads  to  the  assumption  that  the  cell  must  consist  of  two  substances 
which  are  different  in  their  property  of  attracting  water.  He  has  also  tried 
to  determine  the  percentage  relationshiji  between  the  two  cell  constituents 
(stroma  and  intercellular  fluid)  by  the  quantitative  estimation  of  the 
swelling  and  shrinking  of  the  cells  under  the  influence  of  NaCl  solutions  of 


'  Zuntz  iu  Hermann's  Haudbuch  der  Physiol.,  Bd.  4,  Abtb.  2;  Loewy  and  Zuntz, 
PQilgers  Arch..  Bd.  58;  Hamburger,  Du  Bois-Keymond's  Arch.,  1894  and  18!)y,  and 
Zeitsclir.  f.  Biologic,  Bdd.  28  and  35;  v.  Limbeck,  Arch.  f.  cxp.  Patli.  u.  Pbarm.,  Bd. 
35;  GiirOer,  Sitzungsber.  d.  pbys.  nied.  GeseUsch.  zu  Wllrzburg.  1895. 

'  In  regard  to  the  study  of  isotonism  see  Hamburgt-r,  cited  above  and  Virchow's 
Arch.,  Bdd.  140  and  141  ;  Hedin,  Skand.  Arch.  f.  Physiol.,  Bd.  5,  and  Ptliiger's  Arch., 
Bd.  60  ;  Eykman,  ibid.,  Bdd.  60  u.  68  ;  Koejipe,  ibid.,  Bd.  65,  and  Du  Bois-Reymond's 
Arch..  1895. 

'  Arch.  f.  Anat.  u.  Physiol..  Phy.siol.  Abth.,  1898,  S.  317. 


160  TEE  BLOOD. 

different  concentration  or  of  serum  with  different  dilutions.  He  found  the 
volume  of  stroma  for  the  red  as  well  as  the  white  corpuscles  of  the  horse 
was  53-56.1^.  The  volume  of  stroma  for  the  red  corpuscles  in  rabbits  was 
48.7-51,'^,  in  hens  52.4-57.7^,  and  in  frogs  72-76.4^. 

The  question  as  to  the  permeability  of  the  blood-corpuscles  stands  in 
close  connection  to  the  above,  in  other  words,  its  admissibility  for  different 
bodies.  We  have  the  investigations  of  Hambukger,  Gruns,  Eykman, 
and  especially  Hedi]S'  '  on  this  subject.  Hedin's  investigations  have  shown 
that  under  certain  conditions  certain  bodies,  such  as  sugars  and  mannite, 
when  added  to  defibrinated  blood  do  not  penetrate  into  the  blood- 
corpuscles.  Others,  such  as  the  neutral  salts  of  the  free  alkalies,  remain 
chiefly  in  the  plasma  and  only  enter  slightly  into  the  blood-corpuscles. 
x\gain  others,  such  as  ammonium  chloride  and  bromide,  antij^yrin,  mon- 
atomic  alcohols,  divide  themselves  nearly  equally  between  the  corpuscles  and 
the  plasma,  while  others  again,  such  as  ethyl  ether,  are  taken  up  to  a  much 
greater  extent  by  the  corpuscles  than  by  an  equal  volume  of  plasma. 

The  color' of  the  blood  is  red — light  scarlet-red  in  the  arteries  and 
dark/oluish  red  in  the  veins.  Blood  free  from  oxygen  is  dichroitic,  dark 
red  by  reflected  light,  and  green  by  transmitted  light.  The  blood-coloring 
matters  occur  in  the  blood-corpuscles.  For  this  reason  blood  is  opaque  in 
thin  layers  and  acts  as  a  "  deck-farbe. "  If  the  hemoglobin  is  removed 
from  the  stroma  and  dissolved  by  the  blood-liquid  by  any  of  the  above- 
mentioned  means  (see  page  1'37).  the  blood  becomes  transparent  and  acts 
then  like  a  "  lake  color."  Less  light  is  now  reflected  from  its  interior,  and 
this  laky  blood  is  therefore  darker  in  thicker  layers.  On  the  addition  of 
salt  solutions  to  the  blood-corpuscles  they  shrink  and  more  light  is  reflected 
and  the  color  appears  lighter.  A  great  abundance  of  red  corpuscles  makes 
the  blood  darker,  while  by  diluting  with  serum  or  by  a  greater  abundance 
of  white  corpuscles  the  blood  becomes  lighter  in  appearance.  The  different 
colors  of  arterial  and  of  venous  blood  depend  on  the  varying  quantity  of 
gas  contained  in  these  two  varieties  of  blood  or,  better,  on  the  different 
amounts  of  oxyhaemoglobin  and  hemoglobin  they  contain. 

The  most  striking  property  of  blood  consists  in  its  coagulating  within  a 
shorter  or  longer  time,  but  as  a  rule  very  shortly  after  leaving  the  vein. 
Different  kinds  of  blood  coagulate  with  varying  rapidity;  in  human  blood 
the  first  marked  sign  of  coagulation  is  seen  in  2-3  minutes,  and  within 
7-8  minutes  the  blood  is  thoroughly  converted  into  a  gelatinous  mass. 
If  the  blood  is  allowed  to  coagulate  slowly,  the  red  corpuscles  have  time  to 
settle  more  or  less  before  the  coagulation,  and  the  blood-clot  then  shows  an 
npper,  yellowish-gray  or  reddish-gray  layer  consisting   of  fibrin  enclosing 

'  Iledin,  Piliiger's  Arch.,  Bd.  G8,  which  coulains  the  works  of  the  older  investigators 
and  Bd.  70. 


COAGULATION  OF  THE  BLOOD.  161 

chielly  colorless  corpuscles.  This  layer  lias  been  called  crusta  inllammatoria 
or  phlogistic  It.,  because  it  lias  been  especially  observed  in  iiillammatorv 
processes,  and  is  considered  one  of  the  characteristics  of  them.  This 
crusta  or  '''  Iniffy  coiW''  is  not  characteristic  of  any  special  disease,  and  it 
occurs  chiefly  when  the  blood  coagulates  slowly  or  when  the  blood-corpuscles 
settle  more  quickly  than  usual.  A  buffy  coat  is  often  observed  in  the  slow- 
coagulating  equine  blood.  The  blood  from  the  capillaries  is  not  supposed 
to  have  the  power  of  coagulating. 

Coagulation  is  retarded  by  cooling,  by  diminishing  the  oxygen  and 
increasing  the  amount  of  carbon  dioxide,  which  is  the  reason  that  venous 
blood  and  to  a  much  higher  degree  blood  after  asphyxiation  coagulates  more 
slowly  than  arterial  blood.  The  coagulation  may  be  retarded  or  prevented 
by  the  addition  of  acids,  alkalies,  or  ammonia,  even  in  small  quantities;  by 
concentrated  solutions  of  neutral  alkali  salts  and  alkaline  earths,  alkali 
oxalates  and  fluorides;  also  by  egg-albumin,  solutions  of  sugar  or  gum, 
glycerin,  or  mucii  water;  also  by  receiving  the  blood  in  oil.  Coagulation 
may  be  prevented  by  the  injection  of  an  albumose  solution  or  by  an  infusion 
of  the  leech  into  the  circulating  blood,  but  this  infusion  also  acts  in  the 
same  way  on  blood  just  drawn.  Coagulation  is  also  hindered  by  snake-poison 
and  toxalbnmins  (see  pages  124  and  16G).  The  coagulation  may  be  facili- 
tated by  raising  the  temperature;  by  contact  with  foreign  bodies,  to  which 
the  blood  adheres;  by  stirring  or  beating  it;  by  admission  of  air;  by  dilut- 
ing with  very  small  amounts  of  water;  by  the  addition  of  platinum-black  or 
finely  powdered  carbon;  by  the  addition  of  laky  blood,  which  does  not  act 
by  the  presence  of  dissolved  blood-coloring  matters,  but  by  the  stromata  of 
the  blood-corpuscles,  and  also  by  the  addition  of  the  leucocytes  from  the 
lymphatic  glands,  or  a  watery  saline  extract  of  the  lymphatic  glands, 
testicles,  or  thymus.  The  active  constituent  of  such  a  watery  extract  is  the 
nucleoproteid  called  tissue  fibrinogen  or  micleohiston. 

An  important  question  to  answer  is  why  the  blood  remains  fluid  in  the 
circulation,  while  it  quickly  coagulates  when  it  leaves  the  circulation. 

The  reason  why  blood  coagulates  on  leaving  the  body  is  therefore  to  be 
sought  for  in  the  influence  which  the  walls  of  the  living  and  entire  blood- 
vessels exert  upon  it.  These  views  are  derived  from  the  observations  of 
many  investigators.  From  the  observations  of  Hewson,  Lister,  and 
Fredericq  it  is  known  that  when  a  vein  full  of  blood  is  ligatured  at  the 
two  ends  and  removed  from  the  body,  the  blood  may  remain  fluid  for  a  long 
time.     Brucke  •  allowed  the  heart  removed  from  a  tortoise  to  beat  at  0°  C, 

•  Ilewson's  works,  edited  by  Gulliver,  London,  1876.  Cited  from  Gamgee,  Text- 
book of  Physiol.  Chem.,  Vol.  1,  1880.  Lister,  cited  from  Gamgee,  ibid.;  Fredericq, 
"Recherches  sur  la  constitution  dii  plasma  sanguin,"  Gaud,  1878;  Brilcke,  Virchow's 
Arch..  Bd.  12. 


162  THE  BLOOD. 

and  fonnd  that  the  blood  remained  uncoagulated  for  some  days.  The  blood 
from  another  heart  quickly  coagulated  when  collected  over  mercury.  In  a 
dead  heart,  as  also  in  a  dead  blood-vessel,  the  blood  soon  coagulates,  and 
also  when  the  walls  of  the  vessel  are  changed  by  pathological  processes. 

What  then  is  the  iuflnence  which  the  walls  of  the  vessels  exert  on  the 
liquidity  of  the  circulating  blood  ?  Freund  has  found  that  the  blood 
remains  fluid  when  collected  by  means  of  a  greased  canula  under  oil  or  in  a 
vessel  smeared  with  vaseline.  If  the  blood  collected  in  a  greased  vessel  be 
beaten  with  a  glass  rod  previously  oiled,  it  does  not  coagulate,  but  it 
quickly  coagulates  on  beating  it  with  an  unoiled  glass  rod  or  when  it  is 
poured  into  a  vessel  not  greased.  The  non-coagulability  of  blood  collected 
under  oil  has  been  confirmed  later  by  Hatcraft  and  Carlier.  Freuxd 
found  on  further  investigating  that  the  evaporation  of  the  upper  layers  of 
blood  or  their  contamination  with  small  quantities  of  dust  causes  a  coagula- 
tion even  in  a  vessel  treated  with  vaseline.  According  to  Freund,-  it  is  this 
adhesion  between  the  blood  or  between  its  form-elements  and  a  foreign 
substance — and  the  diseased  walls  of  the  vessel  also  act  as  such — that  gives 
the  in^pulse  towards  coagulation,  while  the  lack  of  adhesion  prevents  the 
blood^'from  coagulating.  This  adhesion  of  the  form-elements  of  the  blood 
to  certain  foreign  substances  seems  to  induce  changes  which  apj)arently 
stand  in  a  certain  relationship  to  the  coagulation  of  the  blood. 

The  views  in  regard  to  these  changes  are  very  contradictory.  According 
to  Alex.  Schmidt  "  and  the  Dorpat  school,  an  abundant  destruction  of 
the  leucocytes  takes  place  in  coagulation,  and  important  constituents  for  the 
coagulation  of  the  fibrin  pass  into  the  plasma.  According  to  other  experi- 
menters the  essential  is  not  a  destruction  of  the  leucocytes,  but  an  elimina- 
tion of  constituents  from  the  cells  into  the  plasma.  This  process  is  called 
plasmoscliisis  by  LowiT.^  The  question  whether  the  cell-body  (Giesbach) 
or  the  nucleus  (Liliexfeld ')  takes  part  in  this  process  remains  for  the 
present  undecided.  According  to  BizzozoRO  and  others,  the  leucocytes  are 
not  the  starting-point  in  the  fibrin  formation,  but  rather  the  blood-plates, 

'  Freund,  Wien.  tned.  Jahrb.,  1886  ;  Haycraft  and  Carlier,  Journ.  of  Anat.  and 
Physiol.,  Vol.  23. 

"^  Pfliiger's  Arch.,  Bd.  11.  The  works  of  Alex.  Schmidt  are  found  iu  Arch.  f.  Anat. 
und  Physiol.,  1861,  1862;  Plliiger's  Arch.,  Bdd.  6,  9,  11,  13.  See  especially  Alex. 
Schmidt,  Zur  Blutlehrc  (Leipzig,  1892),  which  also  gives  the  work  of  his  pupils,  and 
Weitere  BeitrUge  zur  Blutlehrc,  1895. 

3  Wien.  Sitzungsber. ,  Bdd.  89  and  90,  and  Prager  med.  TVochenschr.,  1889.  Pe- 
ferred  to  in  Centralbl.  f.  d.  med.  Wi'^sensch..  Bd.  28,  S.  265. 

*  Giesbach,  Pfliiger's  Arch.,  Bd.  50,  and  Centralbl.  f.  d.  med.  Wissensch..  1892; 
Lilienfeld,  Ueber  Leukocyten  und  Blutgerinnung,  Verhandl.  d.  physiol.  Gesellsch. 
zu  Berlin.  No.  11,  1892;  Ueber  den  fliissigen  Zustand  des  Blutes,  etc.,  ibid.,  No.  16, 
1892  ;  and  Weitere  Eeitragc  zur  Kenntnisse  dor  Blutgerinnung,  ibid.,  July,  1883.  Zeit- 
schr.  f.  phvsiol.  Chem.,  Bd,  20. 


AL.   SCHMIDT'S  THEORY.  163 

Although  the  views  on  this  point  are  strongly  divergent,  still  all  investiga- 
tors seem  to  be  united  that  some  constituents  of  the  form-elements  take 
part  in  the  coagulation  of  the  blood. 

WooLDKiDOE*- tjikcs  11  Very  peculiar  position  in  regiud  to  this  question,  namely,  he 
consiilers  the  form-eleuients  us  only  of  secondary  importance  in  coagulation.  As  found 
by  him,  a  peptoue-phisma,  which  has  been  freed  from  all  form-constituents  by  means  of 
centiifugal  force,  yields  abundant  tibrin  when  it  is  not  separated  from  a  substance 
whieli  precipitates  on  cooling.  This  substance,  which  Woolduidgk  has  called  A-fibrin- 
ogen,  seems  to  all  appearances  to  be  a  nucieoproteid,  which,  according  to  the  unani- 
mous view  of  several  investigators,  originates  from  the  form-elements  of  the  blood,  either 
the  blood-plates  or  tlie  leucocytes,  and  the  generally  accepted  view  as  to  the  great  import- 
ance of  the  form-elements  in  the  coagulation  of  the  blood  is  not  really  contrary  to 
Wooldkidge's  experiments. 

Tlie  views  are  greatly  divided  in  regard  to  those  bodies  which  are 
eliminated  from  the  form-elements  of  the  blood  before  and  during  coagula- 
tion. 

According  to  Alex.  Schmidt  the  leucocytes,  like  all  cells,  contain  two 
chief  groups  of  constituents,  one  of  which  accelerates  coagulation,  while  the 
other  retards  or  hinders  it.  The  first  may  be  extracted  from  the  cells  by 
alcohol,  while  the  other  cannot  be  extracted.  Blood-plasma  contains  only 
traces  of  thrombin,  according  to  Schmidt,  but  does  contain  its  antecedent, 
proclirombiu.  The  bodies  which  accelerate  coagulation  are  neither  thrombin 
nor  prothrombin,  but  they  act  in  this  wise  in  that  they  split  off  thrombin 
from  the  prothrombin.  On  this  account  they  are  called  zyinoplastic 
substances  by  Alex.  Schmidt.  The  nature  of  these  bodies  is  unknown, 
and  according  to  Lilie:n"feld  KH^PO^  is  found  amongst  them,  and 
Schmidt  has  given  no  notice  of  their  behavior  to  the  lime  salts,  which  have 
been  found  to  have  zymoplastic  activity  by  other  investigators. 

The  constituents  of  the  cells  which  hinder  coagulation  and  which  are 
insoluble  in  alcohol-ether  are  compound  proteids  and  have  been  called 
cytoglobin  and  preglobulin  by  Schmidt.  The  retarding  action  of  these 
bodies  may  be  suppressed  by  the  addition  of  zymoplastic  substances,  and 
the  yield  of  fibrin  on  coagulation  in  this  case  is  much  greater  than  in  the 
absence  of  the  compound  proteid-retarding  coagulation.  This  last  supplies 
the  material  from  which  the  fibrin  is  produced.  The  process  is,  according 
to  Schmidt,  as  follows:  The  preglobulin  first  splits,  yielding  serglobulin, 
then  from  this  the  fibrinogen  is  derived  and  from  this  latter  the  fibrin 
is  produced.  The  object  of  the  thrombin  is  twofold.  The  thrombin  first 
splits  the  fibrinogen  from  the  paraglobulin  and  then  converts  the  fibrinogen 
into  fibrin.  The  assumption  that  fibrinogen  can  be  split  from  paraglobulin 
has  not  sufficient  foundation  and  is  even  improbable. 

According  to  Schmidt  the  retarding  action  of  the  cells  is  prominent 
during  life,  while  the  accelerating  action  is  especially  pronounced  outside 
of  the  body  or  by  coming  in  contact  with  foreign  bodies.    The  parenchymous 


'  Die  Gerinnung  des  Blutes  (published  by  M.  v.  Frey,  Leipzig,  1891). 


164  THE  BLOOD. 

masses  of  the  organs  and  tissues,  through  which  the  blood  flows  in  tlie 
capillaries,  are  those  cell-masses  which  serve  to  keep  the  blood  fluid  during 
life. 

LiLiENFELD  has  given  farther  proofs  as  to  the  occurrence  in  the  form- 
elements  of  the  blood  of  bodies  which  accelerate  or  retard  the  coagulation. 
According  to  this  author  the  nature  of  these  bodies  is  very  markedly 
different  from  Schmidt's  idea.  While,  according  to  Schmidt,  the  coagu- 
lation-accelerators are  bodies  soluble  in  alcohol,  and  the  compound  proteids 
exhausted  with  alcohol  only  act  retardingly  on  coagulation,  Lilienfeld 
states  that  the  substance  which  acts  acceleratingly  and  retardingly  on 
coagulation  consists  of  a  nucleoproteid,  namely,  nucleohiston.  Nucleohiston 
readily  splits  into  leuconuclein  and  histon,  the  first  of  which  acts  as  a 
coagulation-ex<?itant,  while  the  other,  introduced  into  the  blood-vascular 
system,  either  intravascular  or  extravascular,  robs  the  blood  of  its  property 
of  coagulating.  Introduced  into  the  circulatory  system  the  nucleohiston 
splits  into  its  two  components.  It  therefore  causes  extensive  coagulation 
on  one  side  and  makes  the  remainder  of  the  blood  uncoagulable  on  the 
othery  Lilienfeld's  theory  differs  from  that  of  Alex,  Schmidt  and  most 
other  investigators  in  that  the  fibrin  ferment  is  not  considered  as  a 
precursor,  but  as  a  product,  of  the  coagulation.  The  true  cause  of  coagula- 
tion is  the  leuconucleins,  according  to  Lilienfeld.  The  investigations  of 
LiLiENFELD  are  not  suflBciently  conclusive  for  such  a  view. 

Brucke  showed  long  ago  that  fibrin  left  an  ash  containing  calcium 
phosphate.  The  fact  that  calcium  salts  may  facilitate  or  even  cause  a 
coagulation  in  liquids  poor  in  ferment  has  been  known  for  several  years 
through  the  researches  of  Hammarsten,  Green,  Ringer,  and  Sainsburt. 
The  necessity  of  the  lime  salts  for  the  coagulation  of  blood  and  plasma  was 
first  shown  positively  by  the  important  investigations  of  Artiius  and 
Pages.'  We  are  not  clear  in  regard  to  the  manner  in  which  the  lime  salts 
act. 

According  to  the  generally  accepted  view  of  Artiius  and  Pages  the 
soluble  lime  salts  precipitable  by  oxalate  are  necessary  requisites  for  the 
fermentive  transformation  of  fibrinogen  because  thrombin  remains  inactive 
in  the  absence  of  soluble  lime  salts.  This  view  is  untenable,  as  shown  by 
the  researches  of  Alex.  Schmidt,  Pekelharing,  and  IIammarsten.^ 
Thrombin  acts  as  well  in  the  absence  as  in  the  presence  of  precipitable  lime 
salts. 


'  Hammarsten,  Nova  Acta  reg.  Soc.  Scient.  Upsal  (3),  Bd.  10,  1879;  Green,  Journ. 
of  Physiol.,  Vol.  8;  Ringer  and  Sainsbury,  ihid.,  Vols.  11  and  13  ;  Arthiis  et  Pagfis  and 
Artbus,  see  foot-note,  p.  124;  Hammarsten,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  22. 

'  Hammarsten,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  -2,  wbere  the  other  investigators  are 
cited. 


LILIENFELD'S  AND  PEKELUARING'S  THEORIES.  1G5 

Lilienfeld's  theory  that  the  leuconuclein  splits  off  a  protein  substance, 
t/troiiibosin,  from  the  librinogen,  and  this  thromhosin  forms  an  insoluble 
combination,  thrombosin  lime  (fibrin),  which  separates  with  the  lime 
present,  is  incorrect  according  to  Hammarsten,  Schafer,  and  Cramer.' 
Liliexfeld's  thrombosin  is  nothing  but  fibrinogen  which  is  precipitated 
by  a  lime  salt  from  a  salt-poor  or  salt-free  solution. 

According  to  Pekelharing'  thrombin  is  the  lime  combination  of 
prothrombin,  and  the  process  of  coagulation  consists,  according  to  him,  in 
the  thrombin  transferring  the  lime  to  the  fibrinogen,  which  is  hereby  con- 
verted into  an  insoluble  lime  combination,  fibrin.  The  thrombin  is  hereby 
reconverted  into  prothrombin,  which  again  takes  up  lime  to  be  transformed 
into  thrombin,  which  gives  up  its  lime  to  a  new  portion  of  fibrinogen,  con- 
verting it  into  fibrin;  and  so  on.  Among  the  objections  to  this  theory  we 
can  mention,  among  others,  the  fact  that  fibrin  has  been  obtained  not 
absolutely  free  from  lime,  but  still  so  poor  in  lime  (unpublished  investiga- 
tions of  the  author)  that  if  the  lime,  belongs  to  the  fibrin  molecule  it  must 
be  more  than  ten  times  greater  than  the  ha'moglobin  molecule,  which  is  not 
probable.  These  as  well  as  many  other  observations  decide  that  the  lime 
is  carried  down  by  the  fibrinogen  only  as  a  contamination. 

If,  as  it  seems,  the  lime  is  not  of  importance  in  the  transformation  of 
fibrinogen  into  fibrin  in  the  presence  of  thrombin,  still  this  does  not  con- 
tradict the  above-mentioned  observations  of  Arthus  and  Pages  that  the 
lime  salts  are  necessary  for  the  coagulation  of  blood  and  plasmas.  It  is  very 
probable  that  the  lime  salts,  as  admitted  by  Pekeluarixg,  are  a  necessary 
requisite  for  the  transformation  of  prothrombin  into  thrombin. 

It  is  a  question  whether  the  prothrombin  exists  in  the  plasma  of  the 
circulating  blood  or  whether  it  is  a  body  eliminated  from  tlie  form-elements 
before  coagulation.  Alex.  Schmidt  claims  that  the  circulating  plasma 
contains  prothrombin,  but  Pekeliiaring  disclaims  this.  Blood-plasma 
obtained  by  means  of  leech  infusion  does  not  coagulate  on  the  addition  of 
lime  salts,  but  does  on  the  addition  of  a  prothrombin  solution.  The  form- 
elements,  especially  the  blood-plates,  are  particularly  well  preserved  by  such 
plasma;  and  according  to  Pekelharixg  it  is  probable  that  the  circulating 
plasma  does  not  contain  any  nientionable  amounts  of  prothrombin,  and  that 
this  body  emerges  from  the  form-elements,  perhaps  the  blood-plates,  before 
coagulation.  The  difference  between  the  views  of  Schmidt  and  Pekel- 
HARING  on  this  point  is  as  follows:  According  to  Schmidt  it  is  the  zymo- 
plastic  snbstancfts  which  pass  from  the  form-elements  into  the  plasma  and 
transform  the  prothrombin   existing  preformed    therein.      Pekelharixg 

'  Hiitunuirsten,  I.e.;  Schafer,  Journ.  of  Physiol.,  Vol.  17;  Cramer,  Zeitschr.  f. 
physiol    Chcm.,  Bd.  23. 

'  See  fool-uote  4.  page  127,  and  especially  Virchow's  Festschrift,  Bd.  1,  1891. 


166  THE  BLOOD. 

claims  that  it  is  tlie  prothrooibin  which  passes  from  the  form-elements  into 
the  plasma  and  is  converted  into  thrombin  by  the  lime  salts  of  the  plasma. 

Ill  opposition  to  the  view  of  Alex.  Schmidt,  who  considers  the  fibrin  coagulation  as 
an  enzyraotic  process,  Wooldridge^  is  of  the  opinion  that  the  fibrin  ferment  is  not  the 
cause  of  the  coagulation,  but  is  a  product  of  the  chemical  processes  taking  place  dur- 
ing coagulation.  Wooldkidge  claims,  on  the  contrary,  that  lecithin  and  protein  sub- 
stances containing  lecithin  are  of  the  greatest  importance  in  the  coagulation,  and  the 
<.'ssential  for  the  formation  of  fibrin  is  an  exchange  action  between  two  fibrinogen  sub- 
stances, ^-fibrinogen  and  y^-fibrinogen.  An  exchange  of  lecithin  from  a-fibrinogeu  to 
/i-fibrinogen  takes  place,  and  the  form-elements  are  only  of  minor  importance  for  the 
entire  process.  Halliburton  '  has  presented  weighty  arguments  against  this  theory, 
which  are  not  sulficiently  founded  by  Wooldridge's  obervations. 

Intravascular  coagulation.  It  has  been  shown  by  Alex.  Schmidt  and 
his  students,  as  also  by  Wooldeidge,  Weight,*  and  others,  that  an  intra- 
vascular coagulation  may  be  brought  about  by  the  intravenous  injection 
into  the  circulating  blood  of  a  large  quantity  of  a  thr  )mbin  solution,  as  also 
by  the  injection  of  leucocytes  or  tissue  fibrinogen  (impure  nucleohiston). 
Intravascular  coagulation  may  be  brought  about  also  under  other  conditions, 
such  as  after  the  injection  of  snake-poison  (Maetin"  ^)  or  certain  of  the 
proteid.-like  colloid  substances,  synthetically  prepared  according  to 
CxEiiiAUx's  method  (Hallibueton  and  Pickeeing').  In  rabbits  this 
coagulation  may  extend  through  the  entire  vascular  system,  while  in  dogs 
it  is  ordinarily  confined  to  the  portal  system.  The  blood  in  the  other  parts 
of  the  vascular  system  has  generally  a  decreased  coagulability.  If  too 
little  of  the  above-mentioned  bodies  be  injected,  then  we  observe  only  a 
marked  retarding  tendency  in  the  coagulation  of  the  blood.  According  to 
Wooldeidge  we  can  generally  maintain  that  after  a  short  stage  of  accel- 
erated coagulability,  which  may  lead  to  a  total  or  partial  intravascular 
coagulation,  a  second  stage  of  a  diminished  or  even  arrested  coagulability  of 
the  blood  follows.  The  first  stage  is  designated  (Wooldeidge)  as  the 
'positive  and  the  other  as  the  negative  phase  of  coagulation.  These  state- 
ments have  been  confirmed  by  several  investigators. 

There  is  no  doubt  that  the  positive  phase  is  brought  about  by  an  abun- 
dant introduction  of  thrombin,  or  by  a  rapid  and  abundant  formation  of  the 
same.  According  to  Alex.  Schmidt,  the  zymoplastic  substances  soluble  in 
alcohol  are  active  in  these  processes,  while  according  to  the  investigations 
of  Lilienfeld  this  action  is  caused  more  likely  by  the  leuconucleins  split 
off  from  the  nucleohiston.  According  to  Wooldeidge,  his  tissue  fibrinogen 
does  not  produce  any  intravascular  coagulation  if  it  is  freed  from  contami- 

•  Wooldridge,  1.  c;  Halliburton,  Journ.  of  Physiol.,  Vol.  9. 

'  A  Study  of  the  Intravascular  Coagulation,  etc.,  Proceed,  of  the  Roy.  Irish  Acad. 
(3),  Vol.  2.  See  also  Wright,  Lecture  on  Tissue  or  Cell  Fibrinogen,  The  Lancet,  1892  ; 
and  Wooldridge's  Method  of  Producing  Immunity,  etc.,  Brit.  Med.  Journal,  Sept.,  1891. 

'  .Tourn.  of  Physiol.,  Vol.  15. 

^  Ihid.,  Vol.  18. 


INTRAVASCULAR  COAGULATION.  167 

nating  bodies  by  means  of  alcohol.  This  corresponds  with  the  statements 
of  Alex.  Schmidt,  but  still  furtlier  investigations  are  necessary. 

The  explanation  of  tlie  production  of  the  negative  phase  lias  been 
attempted  in  dilTerent  ways.  Liliexfeld  seeks  the  reason  in  a  cleavage  of 
histon,  which  has  a  retarding  action,  from  the  nncleohiston.  The  retarding 
action  of  histon  has  been  shown,  but  not  its  cleavage  from  nncleohiston  in 
this  process.  According  to  "Wright  and  Pekeliiauixg,  the  retarding 
substances  are  albnmoses,  which  are  formed  in  the  decomposition  of  the 
injected  nucleoproteids.  In  opposition  to  this  view  we  have  the  fact  that 
other  investigators,  as  Halliburton  and  Brodie,'  have  been  nnable  to 
detect  any  albnmose  in  the  blood  or  urine  under  these  conditions.  The 
retarding  action  of  the  poisonous  substance  of  snake-blood,  which  is  not  a 
nucleoproteid,  as  well  as  the  action  of  albumoses,  speaks  against  tlie  assump- 
tion as  to  a  retarding  decomposition  product  of  the  injected  nucleoproteid. 
We  have  a  large  number  of  researches  on  the  action  of  albumoses  by 
different  investigators,  such  as  Grosjean,  Ledoux,'  Contejeax,  Dastre, 
Floresco,  Athanasiu,  Carvallo,  Gley,  Pachox,  Delezenne,'  Spiro, 
and  Ellixger,*  The  chief  result  derived  from  all  these  investigations 
seems  to  be  that  after  the  injection  of  albumoses  a  special  substance  (at 
least  chiefly)  is  formed  in  the  liver,  "^rhis  substance  has  a  retarding  action 
on  coagulation,  hence  the  albnmoses  are  not  directly  active.  If  tiie  l)lood 
has  its  coagulability  returned  some  time  after  an  injection  of  albumose 
solution,  its  coagulation  is  not  prevented  by  another  injection  of  albumoses. 
The  animal  has  become  immune  against  an  albumose  injection,  a  condition 
which  has  been  explained  in  different  ways  (see  Spiro  and  Ellixger). 

Wright  gives  as  reason  why  the  intravascular  coagulation  of  the  blood 
of  a  dog  is  ordinarily  confined  to  the  portal  system  in  the  fact  that  it  con- 
tains larger  quantities  of  carbon  dioxide.  An  increased  quantity  of  carbon 
dioxide  in  the  blood  favors  the  appearance  of  the  positive  phase,  and  an 
intravascular  coagulation,  extending  over  the  entire  vascular  system,  may 
be  produced  in  dogs  that  have  been  asphyxiated  by  clamping  the  trachea,  by 
injecting  tissue  fibrinogen  (impure  nucleohiston).  Delezexxe  '  has  arrived 
at  the  cojiclnsion  by  continued  investigation  that  the  bodies  retarding 
-coagulation  cause  a  hypoleucocytosis,  chiefly  by  their  destructive  action  on 
the  leucocytes.     Tiie  action  of  the  liver  consists  in  that  this  organ  produces 

'  Wright,  \.  c. ;  Lilienfeld,  1.  c;  Pekelbaring,  1.  c. ;  Halliburton  and  Brodie,  Journ. 
of  Physiol.,  Vol.  17. 

'  Grossjean,  Tmvaux  du  laboratoire  dc  L.  Fredeiicq,  4.  Liege,  1892.  Ledoux,  ibid., 
5,  1896. 

'  The  works  of  the  above-mentioned  French  investigators  can  be  found  in  Compt. 
rend.  see.  biol.,  Tomes  46,  47,  and  48,  and  Arch.  d.  Phj-siol.  (5),  Tomes  7,  8,  and  9. 

••  Zeitschr.  f.  physiol.  Chem.,  Bd.  23. 

«  Arch,  de  Physiol.  (5),  Tome  10,  pages  508  and  568. 


168  THE  BLOOD. 

a  special  substance  which  retards  coagulation.  It  consists,  moreover,  in  that 
in  the  cleavage  of  the  nucleohiston  the  leuconuclein,  which  acts  to  enhance 
coagulation,  is  retained  by  the  liver-cells,  while  the  histon,  which  retards 
coagulation,  remains  in  the  blood. 

The  gases  of  the  blood  will  be  treated  of  in  Chapter  XVII  (on  respira- 
tion). 

IV.   The  Quantitative  Composition  of  the  Blood. 

The  quantitative  analysis  of  blood  cannot  be  of  value  for  the  blood  as  an 
entirety.  We  must  ascertain  on  one  side  the  relationship  of  the  plasma  and 
blood-corpuscles  to  each  other,  and  on  the  other  side  the  constitution  of 
each  of  these  two  chief  constituents.  The  difficulties  which  stand  in  the 
way  of  such  a  task,  especially  in  regard  to  the  living,  non-coagulated  blood, 
have  not  been  removed.  Since  the  constitution  of  the  blood  may  differ  not 
only  in  different  vascular  regions,  but  also  in  the  same  region  under 
different  circumstances,  which  renders  also  a  number  of  blood  analyses 
necessary,  it  can  hardly  appear  remarkable  that  our  knowledge  of  the 
constitution  of  the  blood  is  still  relatively  limited. 

The  relative  volume  of  blood-corpuscles  and  serum  in  defibrinated  blood 
may  be  determined,  according  to  L.  and  M.  Bleibtkeu,'  by  various 
methods  if  the  defibrinated  blood  is  mixed  with  different  proportions  of 
isotomic  NaCl  solution  (1  vol.  of  the  blood  to  at  least  1  vol.  salt  solution), 
the  blood-corpuscles  allowed  to  settle  to  the  bottom  or  facilitated  by 
centrifugal  force,  and  the  clear  supernatant  mixture  of  serum  and  common- 
salt  solution  siphoned  off.     The  methods  are  as  follows: 

1.  Determine  the  quantity  of  nitrogen  in  at  least  two  different  portions  of  the  mixture 
of  serum  and  salt  solution  l)y  means  of  Kjeldahl's  method  and  calculate  the  quantity 
of  proleid  corresponding  thereto  by  multiplying  with  6.25,  and  the  relative  volume  of 
blood  X,  and  also  the  volume  of  the  structural  elements  (1—a;),  is  found  by  the  follo-wiug- 
equation  : 

,  .  Si  Si 

[Ci  —  ei)x  =  -^—ei r-  Ci 

In  this  equation  (for  mixtures  1  and  2),  h^  or  bi  represents  the  volume  of  blood  in  the 
mixture,  .Si  or  «a  the  volume  of  salt  solution,  and  Cj  or  d  the  quantity  of  proteid  in  a  cer- 
tain voluine  of  each  mixture. 

2.  Determine  the  specific  gravity  of  the  blood-serum,  the  salt  solutions  and  at  least  one 
of  the  mixtures  of  serum  and  .salt  solution  by  means  of  a  pykuometer.  The  relative 
voluuie  or  serum  x  is  found  in  this  by  the  following  equation  : 

_  s    .S  -  K 

^-  b  ■.>..-!{• 

In  this  equation  s  and  b  represent  the  volumes  of  salt  solution  and  blood  mixed.  /S  rep- 
resents the  specific  gravity  of  the  obtained  serum  and  salt  solution  obtained  on  allowing 
the  l)lood-corpuacles  to  settle,  Su  the  sp.  gr.  of  the  serum,  and  K  that  of  the  salt  solution. 
For  horse's  blood,  two  other,  shorter  methods  may  be  made  use  of  (see  tlie  original 
article). 

'  Pfliiger's  Arch.,  Bdd.  51,  55,  and  60. 


QUANTITATIVE  COMPOSITION  OF  THE  BLOOD.  169 

Important  objections  have  been  presented  by  several  investigators,  such 
as  Eykm.vx,  liiEUNACKi,  and  IIkdix,'  against  tlie  above  nietliotls,  wliose 
vahie  therefore  is  questionable.  8t.  I5u(;ausky  and  'J'anol'  have  sug- 
gested another  method  based  on  the  different  electrical  conductivity  of  the 
blood  and  plasma. 

For  clinical  purposes  the  relative  volume  of  corpuscles  in  the  blood  may 
be  determined  by  the  use  of  a  small  centrifuge  called  hicnuitocrit,  constructed 
by  Blix  and  described  and  tested  by  Hedin.  A  measured  quantity  of 
blood  is  mixed  with  a  known  volume  (best  an  equal  volume)  of  a  Uuid 
which  prevents  coagulation.  This  mixture  is  introduced  into  a  tube  and 
then  centrifuged.  According  to  Hedin  it  is  best  to  treat  the  blood,  which 
is  kept  lluid  by  1  p.  m.  oxalate,  with  an  equal  volume  of  a  i>  p.  m.  XaCl 
solution.  After  complete  centrifugation  the  layer  of  l)lood-corpnscles  is  read 
off  on  the  graduated  tube,  and  the  volume  of  blood-corj)uscles  (or  more 
correctly  the  layer  of  blood-corpuscles)  calculated  in  100  vols,  of  the  blood 
therefrom.  By  means  of  comparative  counts  Hedix  and  Dalaxd  have 
found  that  an  approximately  constant  relation  exists  between  the  volume  of 
the  layer  of  blood-corpuscles  and  the  number  of  red  corpuscles  under 
physiological  conditions,  so  that  the  number  of  corpuscles  may  be  calculated 
from  the  volume.  L) aland'  has  shown  that  such  a  calculation  gives 
approximate  results  also  in  disease,  when  the  size  of  the  blood-corpuscles 
does  not  essentially  deviate  from  the  normal.  In  certain  diseases,  such  as 
pernicious  ana?mia,  this  method  gives  such  inaccurate  results  that  it  cannot 
be  used. 

In  determining  the  relationship  between  the  weight  of  blood-corpuscles 
and  the  weight  of  blood-fluid,  we  generally  i)roceed  in  the  following 
manner : 

If  any  substance  is  found  in  the  blood  which  belongs  exclusively  to  the 
plasma  and  does  not  occur  in  the  blood-corpuscles,  then  the  amount  of 
plasma  contained  in  the  blood  may  be  calculated  if  we  determine  the  amount 
of  this  substance  in  100  parts  of  the  jilasma  or  serum,  respectively,  on  one 
side  and  in  100  parts  of  the  blood  on  the  other.  If  Ave  represent  the 
amount  of  this  substance  in  the  plasma  by  p  and  in  the  blood  by  Z»,  then 

the  amount  of  x  in  the  plasma  from  100  parts  of  blood  is  x  =  '—. 

V 
Such  a  substance,  which  occurs  only  in  the  plasma,  is  fibrin  according 

to  IIoppe-Seylek,  sodium  according  to  Buxge  (in  certain  kinds  of  blood), 
and  sugar  according  to  Otto."  The  experimenters  just  named  have  tried 
to  determine  the  amount  of  the  plasma  and  blood-corpuscles,  respectively, 
in  different  kinds  of  blood,  starting  from  the  above-mentioned  substances. 

Another  method,  suggested  by  Hoppe-Seylek,  is  to  determine  the  total 
amount  of  haemoglobin  and  proteids  in  a  portion  of  blood,  and  on  the  other 
hand  the  amount  of  hfemoglobin  and  proteids  in  the  blood-corpuscles  (from 

'  Biernacki,  Zeitsclir.  f.  pbysiol.  Chem.,  Bd.  19  ;  Eykmau,  Pllliger's  Arcli.,  Bd.  60; 
Hediu,  ibid.,  and  Skaud.  Arch.  f.  Pb^'slol.,  Bd.  5. 

«  Cuntralbl.  f.  Physiol.,  Bd.  11. 

^Hediii,  Skand.  Arch.  f.  Physiol.,  Bd.  2,  S.  361  and  Bd.  5;  Piiflger's  Arch..  Bd. 
60  :  Dalaud,  Fortsclnitte  d.  Med.,  Bd.  9. 

••  Hoppe-Seyler,  Handb.  d.  physiol.  u.  path.  chem.  Analyse,  6.  Aufl.;Buuge,  Zeit 
schr.  f.  Biologic,  Bd.  12;  Ouo,  Plluger's  Arch.,  Bd.  35. 


170  THE  BLOOD. 

an  eqna]  portion  of  the  same  blood),  which  have  been  sufficiently  washed 
with  common-salt  solution  by  centrifugal  force.  The  figures  obtained  as  a 
difference  between  these  two  determinations  correspond  to  the  amount  of 
proteids  which  was  contained  in  the  serum  of  the  first  portion  of  blood. 
If  we  now  determine  the  proteids  in  a  special  portion  of  serum  of  the  same 
blood,  then  the  amount  of  serum  in  the  blood  is  easily  determined.  The 
usefulness  of  this  method  has  been  confirmed  by  Buxge  \)j  the  control 
experiments  with  the  sodium  determinations.  If  the  amount  of  serum  and 
blood-corpuscles  in  the  blood  is  known,  and  Ave  then  determine  the  amount 
of  the  different  blood-constituents  in  the  blood-serum  on  one  side  and  of 
the  total  blood  on  the  other,  the  distribution  of  these  different  blood-con 
stituents  in  the  two  chief  components  of  the  blood,  plasma  and  blood- 
corpuscles,  may  be  ascertained.  On  the  opposite  page  are  given  analyses 
of  various  animal  bloods  by  Abderhaldeis' ^  according  to  Hoppe-Seyler's 
and  Bulge's  methods.  The  analyses  of  human  blood  by  0.  Schmidt^  are 
older  and  were  made  according  to  another  method,  hence  perhaps  the 
results  for  the  Aveight  of  corpuscles  is  a  little  too  high.  All  the  results  are 
in  parts  per  1000  parts  of  blood. 

The  relation  between  blood-corpuscles  and  plasma  may  vary  considerably 
under  different  circumstances  even  in  the  same  species  of  animal.  In 
animals  in  most  cases  considerably  more  plasma  is  formed,  sometimes  f  of 
the  weight  of  the  blood. ^  For  human  blood  Arroxet  has  found  478.8 
p.  m.  blood-corpuscles  and  521.2  p.  m.  serum  (in  defibrinated  blood)  as  an 
average  of  nine  determinations.  Schneider"  found  349.6  and  650.4  p.  m. 
respectively  in  Avomen. 

The  sugar  occurs,  it  seems,  only  in  the  serum  and  not  with  the  blood- 
corpuscles.  The  same  is  true,  according  to  Abderhalden,  for  the  lime, 
fat, "and  perhaps  also  the  fatty  acids.  The  division  of  the  alkalies  between 
the  blood-corpuscles  and  the  plasma  is  different,  as  the  blood-corpuscles 
from  the  pig,  horse,  and  rabbit  contain  no  soda,  those  from  human  blood 
are  richer  in  potassium,  and  the  corpuscles  from  ox-,  sheep-,  goat-,  dog-,  and 
cat-blood  are  considerably  richer  in  sodium  than  potassium.  Chlorine  exists 
in  all  blood  to  a  greater  extent  in  the  serum  than  in  the  blood-corpuscles. 
The  iron  seems  to  occur  entirely  in  the  blood-corpuscles.  Manganese  has 
been  found  in  blood,  as  Avell  as  traces  of  lithium,  coj)per,  lead,  and  silver. 
The  blood  as  a  Avhole  contains  in  ordinary  cases  770-820  p.  m.  water,  with 
180-230  p.  m.  solids;  of  these  173-220  p.  m.  are  organic  and  6-10  p.  m. 
inorganic.  The  organic  consists,  deducting  6-12  p.  m.  extractive  bodies, 
of  proteids  and  haemoglobin.  The  amount  of  this  last-mentioned  body  in 
human  blood  is  about  130-150  p.  m.     In  the  dog,  cat,  pig,  and  horse  the 

'  Zeitscbr.  f.  physiol.  Chem.,  Bdd.  23  nnd  25. 

'  Cited  and  iu  part  recalculated  from  v.  Gonip-Besanez,  Lebrb.  d.  pbysiol.  Chem., 
4.  Aufl.,  S.  345. 

2  See  Sacbarjin  in  Hoppe-Seyler's  Physiol.  Chem.,  S.  447;  Otto,  Pfluger's  Arch.,  Bd. 
35  ;  Bunge,  1.  c. ;  L.  and  M.  Bleibtreu,  Pfluger's  Arch.,  Bd.  51. 

*  Arronet,  Maly's  Jahresber.,  Bd.  17;  Sclmeider,  Cenlrulbl.  f.  Physiol.,  Bd.  5,  S.  362. 


ANALYSES  OF  BLOOD. 


Ill 


quantity  of  hcemoglobin  is  about  the  same,  and  lower  in  the  blood  from  the 
ox,  bull,  sheep,  goat,  and  rabbit  (Abderhalden). 


Water 

Solids 

Haemoglobin 

Proteitl 

Sugar  

Cliolesteriu 

Lecithin 

Fat 

Fatty  acids 

Phosphoric  acid  as  nu-  | 
clein  I 

Soda 

Potash 

Iron  oxide 

Lime 

Magnesia 

Clilorine 

Phoijphoric  acid 

Inorganic  P3O3     


Pigblood. 


O  O"* 

272. '-'0 

162.89 

142.20 

8.35 

0.213 
1.504 

0.027 
0.0455 


2.1.57 
0.696 


0.06.56 
0.64 
0. 89.56 
0.7194 


518.36 
46.54 

.38.26 
0.684 
0.231 
0.805 
1.104 
0.448 

0.0123 

2.401 
0.152 

0.0689 

0.0233 

2.048 

0.1114 

0.0296 


Ox-blood. 


192.6.5 
132.85 
103.10 
20.89 

1. 100 
1.220 


0.0178 

0.7266 
0.2351 
0..544 

0.00.56 
0.5901 
0.2392 
0.1140 


616.25 
58.249 

48.901 
0.708 
0.8.35 
1.129 
0.625 

0.0089 

2.9084 
0.1719 

0.0S05 
0.0:500 
2.4889 
0.1646 
0.0571 


Horse-blood 

Dog-blood. 

Bull-blood. 

Sheep- 

CO 

M 

X 

Oi 

U 

u 

u 

0 

^¥'- 

ff« 

^g.X 

fi'^ 

J.  a". 

F'. 

^a'^ 

^S 

%n 

0  SS 

?-!2 

_2  OTO 

a 

M 

aa 

V2 

25 

M 

— 

243.87 

551.14 

277.71 

.514.30 

206.81 

608.03 

200.. 39 

153.84 

51.15 

165.10 

42.89 

127.50 

57.66 

118.8-.' 

125.8 



145.6 



106.40 



102. HO 

20.05 

42.65 

2.36 

34.05 

15.38 

46.41 

12.80 

— 

0.90 



0.74 



0.679 

. 

0.26 

0.31 

0.56 

0..37 

0.610 

0.599 

1.147 

1.93 

1.05 

1.02 

0.98 

0.953 

1.244 

1.329 

_ 

0.50 



0.91 



2.357 



0.02 

0.36 

— 

0.70 

— 

0.494 

— 

0.05 

0.01 

0.05 

0.01 

0.0194 

0.0089 

0.0235 

_ 

2.62 

1.27 

2.39 

0.8.39 

2.873 

0.760 

1.32 

0.15 

0.11 

0.14 

0.2.33 

0.174 

0.236 

0.59 



0.71 



0.562 



0.545 

— 

0.07 



0.06 



0.073 



0.04 

0.03 

0.03 

0.03 

0.009 

0.027 

0.006 

0.18 

2.20 

0.60 

2.31 

0.6-.'8 

2.453 

0.575 

0.98 

0.15 

0.67 

0.14 

0.236 

0.156 

0.228 

0.76 

0.05 

0.54 

0.05 

0.133 

0.041 

0.088 

624.16 
5«.6:j 

46.56 
0.708 
0.891 
1.088 
0.8.59 
0.4908 

0.0109 

2.017 
0.172 

0.089 
0.027 
2.516 
0.163 
0.057 


Water 

Solids 

Haemoglobin 

Proteid 

Sugar     

Chole-sterin 

Leciihiu  

Fat  

Fatty  acids 

Phosphoric  acid  as  uu- 1 
clein.  )" 

Soda  

Potash 

Iron  oxide 

Lime 

Maenesia , 

Chlorine 

Phosphoric  acid 

Inorganic  PjOj 


-       1 


Goat-blood. 

Cat-blood. 

Rabbit-blood. 

y- 

x 

0 

V 

» 

0 

^ 

0 

3  -, 

^'ao 

-ia° 

r-'O 

5  — 

Z-A 

~\.~ 

^  0  ^ 

sJ5 

S^- 

°  c?i 

ji   UTO 

0  o-<s' 

z^ 

^  0  « 

%■■=' 

33 

'X 

» 

m 

cn 

t/2 

211.35 

592.54 

270.90 

524.17 

235.74 

518.18 

135.80 

00.25 

163.11 

41.35 

136.37 

46.71 

11 2. .50 

— 

143.2 



123.. 50 



18.76 

.50.96 

11.62 

33.16 

4.55 

33  63 

— 

0.822 



0.860 

— 

1.036 

0.601 

0.698 

0..5.56 

0.339 

0.268 

0.343 

1.339 

1.127 

1.354 

0.971 

1.722 

1.105 



0.0407 



0.446 

— 

0.749 

0.398 

— 

0.282 

— 

0.507 

0.0  J8 

0.0117 

0.063 

0.009 

0.040 

0.015 

0.755 

2.824 

1.174 

2.512 



2.7S9 

0.2.^6 

0.160 

0.112 

0.148 

1.946 

0.162 

0.547 



0.694 



0.615 



— 

0.078 



0.062 

— 

0.072 

0.014 

0.026 

0.0.35 

0.024 

0.029 

0.028 

0.514 

2.409 

0.4.55 

2.300 

0.460 

2.438 

0.243 

0.1.54 

0.097 

0.133 

0.835 

0.151 

0.097 

0.045 

0.515 

0.040 

0.645 

0.040 

Human  Blood, 
Man. 


Human  Blood, 
Woman. 


2  oi- 

n 


349.69 
163.33 


Organic 
}■    bodies 
159.59 


Inorg. 
3.74 


0.24 
1.59 


0.90 


03 

0 

pa 

439.02 
47.96 

272.. 56 

123.681 

43.63 

120.13 

4.14 

3.55 

1.66 
0.15 

0.65 
1.41 

1.72 

0.36 

- 

~ 

—         .0 


46.70 


5.07 

1.92 
0.20 


0.14 


The  amount  of  sugar  in  the  blood  is  on  an  average  1-1.5  p.  m.  It 
seems  to  be  dependent  upon  the  constitution  of  the  food,  as  feeding  with 
large  amounts  of  sugar  or  dextrin  causes  a  considerable  increase  in  the  sugar 
of  the  blood,  as  observed  by  Bleile.  When  the  quantity  of  sugar  amounts 
to  more  than  3  p.  m.,  then,  according  to  Cl.  Berxard,'  sugar  appears  in 
the  urine,  and  also  a  glycosuria.     In  judging  of  the  amount  of  sugar  in  the 


^  Bleile,  Du  Bois-Reymond's  Arch.,  1879;  Bernard,  Le9ons  sur  le  diab^te.     Paris,  1877. 


172  TEE  BLOOD. 

blood  we  have,  in  most  cases,  overlooked,  the  fact  that  the  reducing  power 
of  the  blood  is  not  due  to  sugar  alone  but  also,  and  perhaps  in  greater  part, 
to  a  jecoriu-like  substance  (see  page  133).  According  to  Hexeiques  '  the 
blood  contains  under  normal  conditions  only  inconsiderable  amounts  of 
sugar,  and  the  reducing  power  depends  essentially  upon  the  jecorin.  An 
increase  in  the  quantity  of  sugar  takes  place,  as  first  observed  by  Beexaed 
and  lately  substantiated  by  Fe.  Schekck,^  after  removal  of  blood.  Accord- 
ing to  Hexriques  this  increase  of  the  reducing  power,  at  least  in  dogs,  is 
not  due  to  sugar  but  chiefly  to  jecorin.' 

The  quantity  of  urea,  which  according  to  Schoxdoeff  is  equally 
divided  between  the  blood-corpuscles  and  the  plasma,  is  greater  on  taking 
food  than  in  starvation  (Geehaxt  and  Qeixquaud,  Schoxdoeff)  and 
varies  between  0.2  and  1.5  p.  m.  In  dogs  Schoxdoeff^  found  in  starva- 
tion aminimum  of  0.348  p.  m.  and  a  maximum  of  1.529  p.  m.  at  the  point 
of  highest  urea  formation.  Blood  also  contains  traces  of  ammonia,  which 
amounted  to  1.5  milligrams  for  100  grams  arterial  dog-blood  (Xexcki, 
Pawloav  and  Zaleski).  The  quantity  of  ammonia  in  the  blood  from 
the  portal  vein  is  about  3.4  times  greater,  but  the  greatest  ezists  in  the  blood 
from  the  branches  of  the  portal  vein,  namely,  the  pancreatic  veins,  where 
it  amounts  to  11.2  milligrams.  The  blood  from  healthy  persons  contains 
on  an  average  0.90  milligrams  per  100  c.c.  according  to  Wixteebeeg.^ 
The  quantity  of  uric  acid  may  be  0.1  p.  m.  in  bird's  blood  (y.  Soheodee'). 
Lactic  acid  was  first  found  in  human  blood  by  Salomox  and  then  by 
Gaglio,  Beelixeeblau  and  Ieisawa.''  The  quantity  of  lactic  acid  may 
vary  considerably.     Beelixeeblau  found  0.71  p.  m.  as  maximum. 

The  Composition  of  the  Blood  in  Different  Vascular  Regions   and  under 

Different  Conditions. 

Arterial  and  Venous  Blood.  The  most  striking  difference  between 
these  two  kinds  of  blood  is  the  variation  in  color  caused  by  their  containing 
different  amounts  of  gas  and  different  amounts  of  oxylijemoglobin  and 
haemoglobin.     The  arterial  blood  is  light  red;  the  venous  blood  is  dark  red, 

'  Zeitsclir.f.  physiol.  C'bem.,  Bd.  23.  See  also  Kolisch  and  Stejska],  Wieu.  kliu. 
WocLensclir.,  1898. 

«  Pflilgei's  Arch.,  Bd.  57. 

'  A  critical  review  of  tbe  different  methods  for  removing  proteids  from  the  blood  in 
the  estimation  of  sugar  has  been  given  by  Seegen,  Centralbl.  f.  Physiol.,  Bd.  6. 

^  Greiiaiit  ct  Quiuquaud,  Jourual  de  1  aiiatoniie  et  de  la  physiol.,  Tome  20,  and 
Compt.  rend..  Tome  98  ;  Schondorff,  Ptiuger'.s  Arch.,  Bdd.  54  and  63. 

'  Nencki,  Pawlow,  and  Zale-ski,  Arch,  de  scieuc.  biol.  de  St.  Pttersbourg,  Tome  4; 
Winterberg,  Wien.  kiln.  TVochenschr.,  1897;  and  Zeitschr.  f.  kliu.  Med.,  Bd.  35. 

«  Ludwig's  Festschrift,  1887. 

'  Irisawa,  Zeitschr.  f.  physiol.  Chem.,  Bd.  17,  which  also  gives  the  older  literature. 


BLOOD  FROM  DIFFERENT    VASCULAR  REGIONS.  173 

dichroitic,  greenish  by  transmitted  light  through  tliin  layers.  The  arterial 
coagulates  more  quickly  tiian  tiie  venous  blood.  The  latter,  on  account  of 
the  transudation  which  takes  place  in  the  capillaries,  is  somewhat  poorer  in 
water  but  richer  in  blood-corpuscles  and  haemoglobin  than  the  arterial 
blood,  but  this  is  denied  hy  modern  investigators.  According  to  Krugek' 
and  his  pupils  the  quantity  of  dry  residue  and  haemoglobin  in  blood  from 
the  carotid  artery  and  from  the  jugular  vein  (in  cats)  are  the  same. 
RoiiMANN  and  Muhsam' could  not  detect  any  dillerence  in  the  quantity 
of  fat  in  arterial  and  venous  blood. 

Blood  from  the  Portal  Vein  and  the  Hepatic  Vein.  The  blood  of  the 
hepatic  vein  is  poorer  in  ordinary  red  blood-corpuscles  but  richer  in  white 
and  so-called  young  red  blood-corpuscles.  A  few  investigators  have  con- 
cluded from  this  that  a  formation  of  red  blood-corpuscles  takes  place  in  the 
liver,  while  others  claim  that  a  destruction  takes  place. 

In  consequence  of  the  small  quantities  of  bile  and  lymph  found  relatively 
to  the  large  quantity  of  blood  circulating  through  the  liver  in  a  given  time, 
we  can  hardly  expect  to  detect  a  jiositive  difference  in  the  comjiosition 
between  the  blood  of  the  portal  and  hepatic  veins  by  chemical  analysis. 
The  statements  in  regard  to  such  a  difference  are  in  fact  contradictory. 
For  example,  Drosdoff  has  found  more  haemoglobin  in  the  hepatic  than  in 
the  portal  vein,  while  Otto  found  less.  Kruger  finds  that  the  quantity  of 
haemoglobin,  as  Avell  as  the  solids,  in  the  blood  from  the  vessels  passing  to 
and  from  the  liver  is  different,  but  a  constant  relationshij)  cannot  be 
determined.  The  disputed  question  as  to  the  varying  quantities  of  sugar 
in  the  portal  and  hepatic  veins  will  be  discussed  in  a  following  chapter  (see 
Chapter  VIII,  on  the  formation  of  sugar  in  the  liver).  After  a  meal  rich 
in  carbohydrates  the  blood  of  the  portal  vein  not  only  becomes  richer  in 
dextrose,  but  may  contain  also  dextrin  and  other  carbohydrates  (v.  ]MERiN'r;, 
Otto').  The  amount  of  urea  in  the  blood  from  the  hepatic  vein  is  greater 
than  in  other  blood  (Grehant  and  Quinquaud*).  In  regard  to  the 
quantity  of  ammonia,  see  page  172. 

Blood  of  the  Splenic  Vein  is  decidedly  richer  in  leucocytes  than  the 
blood  from  the  splenic  artery.  The  red  blood-corpuscles  of  the  blood  from 
the  splenic  vein  are  smaller  than  the  ordinary,  less  flattened,  and  show  a 
greater  resistance  to  water.  Tlio  blood  from  the  splenic  vein  is  also  claimed 
to  be  richer  in  water,  fibrin,  and  proteid  than  the  ordinary  venous  blood. 
According  to  v.  ^Iiddexdorff,  it  is  richer  in  haemoglobin  than  arterial 


'  Zeitschr.  f.  Biologic,  Bd.  26. 
'  Pfluger's  Archiv,  Bd.  46. 

'  Drosdorff.   Zeitschr.   f.   physiol.   Chem.,  Bd.  1;  Otto,  Maly's  Jahresber.,  Bd.  17 
V.  Meiiug,  Du  Bois-Reymond's  Arch.,  1877,  S.  413. 
M.  c. 


174  THE  BLOOD. 

blood.  Kruger  *  and  his  pnpils  have  found  that  the  blood  from  the  vena 
lienalis  is  generally  richer  in  hemoglobin  and  solids  than  arterial  blood ;  still 
the  contrary  is  often  found.  The  blood  from  the  splenic  vein  coagulates 
slowly. 

The  Blood  from  the  Veins  of  the  Glands.  The  blood  circulates  with 
greater  rapidity  through  a  gland  daring  activity  (secretion)  than  when  at 
rest,  and  the  outflowing  venous  blood  has  therefore  during  activity  a  lighter 
red  color  and  a  greater  amount  of  oxygen.  Because  of  the  secretion  the 
venous  blood  also  becomes  somewhat  poorer  in  water  and  richer  in  solids. 

The  blood  from  the  Muscular  Veins  shows  an  opposite  behavior,  for 
daring  activity  it  is  darker  and  more  venous  in  its  properties  because  of  the 
increased  absorption  of  oxygen  by  the  muscles  and  still  greater  production 
of  carbon  dioxide  than  when  at  rest. 

2fenstrual  Blood  has,  according  to  an  old  statement,  not  the  power  of 
coagulating.  This  statement  is  nevertheless  false,  and  the  apparent  tin- 
coagulability  depends  in  part  on  the  womb  and  the  vagina  retaining  the 
blood-clot,  so  that  only  fluid  cruor  is  at  times  eliminated,  and  in  part  on  a 
contamination  with  vaginal  mucus  which  disturbs  the  coagulation. 

The  Blood  of  the  two  Sexes.  Woman's  blood  coagulates  somewhat  more 
quickly,  has  a  lower  specific  gravity,  a  greater  amount  of  water,  and  a 
smaller  quantity  of  solids  than  the  blood  of  man.  The  amount  of  blood- 
corpuscles  and  hsemoglobin  is  somewhat  smaller  in  woman's  blood.  The 
amount  of  haemoglobin  is  146  p.  m.  for  man's  blood  and  133  p.  m.  for 
woman's. 

'Dvivmg  pregnancy  Nasse  has  observed  a  decrease  in  the  specific  gravity,, 
with  an  increase  in  the  amount  of  water  until  the  end  of  the  eighth  month. 
From  then  the  specific  gravity  increases,  and  at  delivery  it  is  normal  again. 
The  amount  of  fibrin  is  somewhat  increased  (Becquerel  and  Eodier,, 
Nasse).  The  number  of  blood-corpuscles  seems  to  decrease.  In  regard  to 
the  amount  of  haemoglobin  the  statements  are  somewhat  contradictory, 
Cohnstein"  found  the  number  of  red  corpuscles  diminished  in  the  blood 
of  pregnant  sheep  as  compared  to  non-pregnant,  but  the  red  corpuscles 
were  larger,  and  the  quantity  of  haemoglobin  in  the  blood  was  greater  in  the 
first  case. 

The  Blood  at  Different  Periods  of  Life.  Fcntal  blood  is  strikingly 
poorer  in  blood-corpuscles  and  haemoglobin  than  the  blood  of  the  adult.  A 
few  hours  after  birth  the  blood  of  the  child  has  the  same  or  greater  quantity 
of  haemoglobin  than  the  blood  of  the  mother  (Cohnsteik  and  Zuntz, 
Otto,  Winternitz).     The  quantity  of  haemoglobin  and  blood-corpuscles 

'  V.  Middendorff,  Central bl.  f.  Physiol.,  Bd.  2,  S.  753  ;  Kruger,  1.  c. 
*  Nasse,  Maly's  .Jahresber.,  Bd.  7;    Becquerel    and  Rodier,  Traite  de  chim.  pathol» 
Paris,  1854  ;-Colinstein,  PflUger's  Arch.,  Bd.  34. 


INFLUENCE  OF  FOOD   ON  TUE  BLOOD.  175 

quickly  increases  after  birth;  still  they  do  not  both  increase  at  the  same 
rate,  as  the  anionnt  of  hiemoglobin  increases  much  faster.  Two  or  three 
days  after  birth  the  hfemoglobiu  reaches  a  maximum  (20-21^),  which  is 
greater  than  at-  any  other  period  of  life.  Tliis  is  the  cause  of  the  great 
abundance  of  solids  in  the  blood  of  new-born  infants  as  observed  by  several 
investigators.  The  quantity  of  haemoglobin  and  blood-corpuscles  sinks 
gradually  from  this  first  maximum  to  a  minimum  of  about  W'fo  iuumoglobin, 
which  nunimum  appears  in  human  beings  between  the  fourth  and  eighth 
years.  The  quantity  of  haemoglobin  then  increases  again  until  about  the 
twentieth  year,  when  a  second  maximum  of  13.7-15^  is  reached.  The 
haemoglobin  remains  at  this  point  only  towards  the  forty-fifth  year,  and 
then  gradually  and  slowly  decreases  (Leichtensterx,  Otto  ').  According 
to  older  statements,  the  blood  at  old  age  is  poorer  in  blood-corpuscles  and 
albuminous  bodies  but  richer  in  water  and  salts.  Tlie  more  recent  investi- 
gations of  W.  ScHwixGE^  on  the  quantity  of  haemoglobin  and  the  number 
of  red  and  Avhite  corpuscles  in  human  beings  at  different  periods  of  life 
under  various  conditions,  show  that  the  quantity  of  lu^moglobin  and  the 
number  of  tlie  red  blood-corpuscles  is  greatest  immediately  after  birth,  then 
soon  sinks  to  a  miuimnm,  and  then  increases  again  as  growth  j^rogresses. 
In  maturity  they  show  certain  periodic  variations  until  finally  towards  the 
end  of  life  they  decrease  again.  The  number  of  leucocytes  on  the  contrary 
decrease  from  growth  to  maturity  but  later  increase, 

TJie  Inflnoice  of  Food  o)i  the  Blood.  In  complete  starvation  no  decrease 
in  the  amount  of  solid  blood  constituents  is  found  to  take  place  (PANUii 
and  others).  The  amount  of  haemoglobin  is  a  little  increased  (Subbotin, 
Otto),  and  also  the  niimber  of  red  blood-corpuscles  increases  (^YoR^I 
MuLLER,  Buntzen),  whicli  probably  depends  on  the  fact  that  the  blood- 
corpuscles  are  not  so  quickly  transformed  as  the  serum.  In  rabbits  and  to 
a  less  extent  in  dogs,  Popel  ^  found  that  complete  abstinence  had  a  tendency 
to  increase  the  specific  gravity  of  the  blood.  The  amount  of  fat  in  the 
blood  may  be  somewhat  increased  in  starvation  because  the  fat  is  taken  up 
from    the   fat   deposits   and    carried    to    the  various  organs    by  the    blood 

(N.   SCHULZ*). 

After  a  rich  meal  the  relative  number  of  blood-corpuscles,  after  secretion 
of  digestive  juices  or  absorption  of  nutritive  liquids,  may  be  increased  or 

'  Cobnstein  and  Zuntz,  Pflliger's  Arch.,  Bd.  34;  AVintemitz.  Zeitschr.  f.  pliysiol. 
Chem.,  Bd.  23;  Lcichteusterii,  Uiitersuch.  ilber  den  Hamoglobingebalt  des  Blutes, 
etc.     Leipzig,  1878  ; — Olto,  ^Maly's  Jabiesber.,  Bdd.  15  and  17. 

=  Pauger's  Arcii.,  Bd.  73. 

*  Paniim,  Virchow's  Arch.,  Bd.  29  ;  Subbotiu,  Zeitschr.  f.  Biologic,  Bd.  7  ;  Otto,  1.  c. ; 
Worm  Miiller,  Transfusion  nnd  Pletliora.  Cbristianla,  1875 , — Buntzen,  see  Maiy's 
Jabresber.,  Bd.  9; — Popel,  Arcb.  des  scienc.  biol.  de  St.  Petersbourg,  Tome  4,  p.  354. 

*Pflagev's  Arcb.,  Bd.  65. 


176  THE  BLOOD. 

diminished  (Buntzen,  Leichtexstern).  The  number  of  white  blood- 
corpuscles  may  be  considerably  increased,  after  a  diet  rich  in  proteids. 
After  a  diet  rich  in  fat  the  plasma  becomes,  even  after  a  short  time,  more 
or  less  milky-white,  like  an  emulsion.  The  constitution  of  the  food  acts 
essentially  on  the  amount  of  hsemoglobin  in  the  blood.  The  blood  of 
herbivora  is  generally  poorer  in  haemoglobin  than  that  from  carnivora,  and 
SuBBOTiJsr  has  observed  in  dogs  after  a  partial  feeding  with  food  rich  in 
carbohydrates  that  the  amount  of  haemoglobin  sank  from  the  physiological 
average  of  137.5  p.  m.  to  103.2-93.7  p.  m.  According  to  Leichten"STERX 
a  gradual  increase  in  the  amount  of  haemoglobin  is  found  to  take  place  in 
the  blood  of  human  beings  on  enriching  the  food,  and  according  to  the 
same  investigator  the  blood  of  lean  persons  is  generally  somewhat  richer  in 
hemoglobin  than  blood  from  fat  ones  of  the  same  age.  The  addition  of 
iron  salts  to  the  food  greatly  influences  the  number  of  blood-corpuscles  and 
especially  the  amount  of  haemoglobin  they  contain.  The  action  of  the  iron 
salts  is  obscure.  According  to  Bijxge  and  his  pupils,  they  probably  com- 
bine with  the  sulphuretted  hydrogen  of  the  intestinal  canal  and  thereby 
preven^;  the  iron,  associated  in  the  food  as  protein  combination,  from  being 
eliminated  as  iron  sul2)hide.  According  to  numerous  other  investigators, 
such  as  Woltering,  Kunkel,  Macullum,  W.  Hall,  Hochhaus,  and 
Quiif  cke  and  Gaule,  therapeutic  iron  is  also  absorbed  and  is  of  value  in  the 
formation  of  haemoglobin.' 

An  increase  in  the  numler  of  red  corpuscles^  a  true  "  plethora  polt- 
CYTH^jiiCA,"  takes  place  after  transfusion  of  blood  of  the  same  species  of 
animal.  According  to  the  observations  of  Paxum  and  Worm  Muller,' 
the  blood-liquid  is  quickly  eliminated  and  transformed  in  this  case, — the 
water  being  eliminated  principally  by  the  kidneys,  and  the  proteid  burned 
into  urea,  etc., — while  the  blood-corpuscles  are  preserved  longer  and  cause  a 
*'  POLYCYTHEMIA."  A  relative  increase  in  the  number  of  red  corpuscles  is 
found  after  abundant  transudations  from  the  blood,  as  in  cholera  and 
heart-failure,  with  considerable  accumulation.  An  increase  in  the  number 
of  red  blood-corpuscles  has  also  been  observed  nnder  the  influence  of 
diminished  pressure  or  in  high  altitudes.  Viault  first  called  attention  to 
the  fact  that  the  number  of  red  corpuscles  was  very  great  in  the  blood  of 
man  and  animals  living  in  high  regions.  According  to  him  the  llama  has 
about  IG  million  blood-corpuscles  per  c.mm.  By  observations  on  himself 
and  others,  as  well  as  on  animals,  Viault  found  the  first  effect  of  sojourning 
in  high  localities  was  a  very  considerable  increase  in  the  number  of  red 

•  Bunge,  Zeitschr.  f.  physiol.  Cbem.,  Bd.  9;  Hiluserraann,  ihid.,  Bd.  23,  where  the 
works  of  Weltering,  Gaule,  Hall,  Hochhaus,  and  Quincke  are  cited.  The  same  work 
contains  a  table  of  the  quantity  of  iron  in  various  foods;  Kunkel,  Pflilger's  Arch.,  Bd. 
61  ;  Macullum,  Journal  of  Physiol.,  Vol.  16. 

*  Panum.  Virchow's  Arch..  Bd.  29  ;  Worm  Mtiller,  1.  c. 


VARIATION  IN  THE  NUMBER  OF  RED   CORPUSCLES.  177 

corpuscles,  iii  his  own  case  5-8  millions.  A  similar  increase  of  the  red 
blood-corpuscles,  as  also  an  increase  in  the  quantity  of  hajmoglobin  under 
the  inlluence  of  diminished  pressure,  has  been  observed  by  many  other 
investigators  in  human  beings  as  well  as  in  animals.  The  experimenters  are 
not  united  as  to  whether  this  increase  is  absolute  or  only  relative,  caused  by 
a  concentration  of  the  blood  produced  by  a  withdrawal  from  the  plasma  into 
the  lympliatics  or  by  other  conditions.' 

A  decrease  in  the  Qiumher  of  red  corpuscles  occurs  in  anaemia  from  differ- 
ent causes.  Very  excessive  hemorrhage  causes  an  acute  anaemia,  or  more 
correctly  oligemia.  Even  during  the  hemorrhage  the  remaining  blood 
becomes  richer  in  water  by  diminished  secretion  and  excretion,  as  also  by 
an  abundant  absorption  of  parenchymoas  fluid,  somewhat  poorer  in  proteids 
and  strikingly  poorer  in  red  blood-corpuscles.  The  oligemia  passes  soon 
into  a  hydroemiiu  The  amount  of  proteid  then  gradually  increases  again; 
but  the  re-formation  of  the  red  blood-corpuscles  is  slower,  and  after  the 
hydraemia  follows  also  an  oligocythaemia.  After  a  little  time  the  number  of 
blood-corpuscles  rises  to  normal;  but  the  re-formation  of  haemoglobin  does 
not  keep  pace  with  the  re-formation  of  the  corijuscles,  and  a  chlorotic  con- 
dition may  appear.  A  considerable  decrease  in  the  number  of  red  corpuscles 
occurs  also  in  chronic  anaemia  and  chlorosis;  still  in  such  cases  an  essential 
decrease  in  the  amount  of  haemoglobin  occurs  without  an  essential  decrease 
in  the  number  of  blood-corpuscles.  The  decrease  in  the  amount  of  haemo- 
globin is  more  characteristic  of  chlorosis  than  a  decrease  in  the  number  of 
red  corpuscles. 

A  very  considerable  decrease  in  the  number  of  red  corpuscles  (300,000- 
400,000  in  1  c.mm.)  and  diminution  in  the  amount  of  haemoglobin  (^-^V) 
occurs  in  pernicious  anaemia  (Hayem,  Laache,  and  others).  On  the 
contrary,  the  individual  red  corpuscles  are  larger  and  richer  in  haemoglobin 
than  they  ordinarily  are,  and  the  number  stands  in  an  inverse  relationship 
to  the  amount  of  liEemoglobin  (IIayem).  Besides  this  the  red  corpuscles 
often,  but  not  always,  show  in  jiernicions  anaemia  remarkable  and  extraor- 
dinary irregularities  of  form  and  size,  which  Quincke'  has  termed  p oik ilo- 
cytosis. 

TJie  Composition  of  the  Red  Corptiscles.  Irrespective  of  tlie  changes  in 
the  amount  of  haemoglobin,  as  just  mentioned,  the  composition  of  the  blood- 

'  See  Viault,  Compt.  rend..  Tome  111,  112,  and  114  ;  MUntz,  ibid.,  112;  Regnard, 
Compt.  rend.  Sec.  de  biol.,  Tome  44.  The  works  of  Miescber  and  bis  coworkers  are 
found  in  "Die  bislocbemiscben  und  pbysioi.  Arbeiten  von  Friedricb  Miescber,"  Leip- 
zig, 1897.  (Bunge  and)  Weiss,  Zeitschr.  f.  pbysioi.  Cbera.,  Bd.  22;  Giacosa,  tbid.,  Bd. 
23;  Grawitz,  Berl.  klin.  Wocbeuscbr.,  1895;  Loewy  and  Zuntz,  PflUger's  Arcb.,  Bd. 
66  ;  Scbaumanu  and  llosenquist,  Zeiiscbr.  f.  klin.  Med.,  1898. 

'  Laacbe,  "Die  Anilmie"  (Cbristiania,  1883),  wbicb  also  contains  the  literature; 
Quincke,  Deutscb.  Arcb.  f.  klin.  Med.,  Bdd.  20  and  25. 


178  THE  BLOOD. 

corpascles  may  be  changed  in  otlier  ways.  By  abundant  transudations,  as 
in  cholera,  the  blood-corpascles  may  give  up  water,  potassium,  and  phos- 
phoric acid  to  the  concentrated  plasma  and  become  correspondingly  richer 
in  organic  substances  (C.  Schmidt').  By  a  few  other  transudation 
processes,  as  in  dysentery  and  dropsy  with  albuminuria,  a  considerable 
amount  of  proteid  passes  from  the  blood;  the  plasma  becomes  richer  in 
water,  and  the  blood-corpuscles  take  up  water  and  so  become  poorer  in 
organic  substance  (C.  Schmidt). 

The  numhcr  of  leucocytes  may,  as  above  mentioned,  increase  considerably 
under  physiological  conditions,  such  as  after  a  meal  rich  in  proteids 
(physiological  leucocyfcosis).  Under  pathological  conditions  a  hyperleuco- 
cytosis  may  occur,  and  according  to  Vikchow  ^  this  occurs  in  all  pathological 
processes  in  which  the  lymphatic  glands  take  part.  Leucocytosis  occurs 
prominently  in  lenc«mia,  which  is  characterized  by  the  very  great  abun- 
dance of  leucocytes  in  the  blood.  The  number  of  leucocytes  is  not  only 
absolutely  increased  in  this  disease,  but  also  in  proportion  to  the  number  of 
red  blood-corpuscles,  which  is  considerably  diminished  in  leucasmia.  The 
blood  from  a  leucaemic  patient  has  a  lower  specific  gravity  than  the  ordinary 
(1.035-1.040)  and  a  lighter  color,  as  if  it  were  mixed  with  pus.  The 
reaction  is  alkaline,  but  after  death  is  often  acid,  probably  due  to  a  decom- 
position of  the  considerably  increased  lecithin.  In  leucaemic  blood,  volatile 
fatty  acids,  lactic  acid,  glycero-phosphoric  acid,  large  amounts  of  xanthin 
bodies,  and  the  so-called  Charcot's  crystals  (see  Chapter  XIII)  have  been 
found. 

The  ciuantity  of  tvater  in  the  blood  is  increased  in  general  dropsy,  with 
or  without  kidney  disease,  in  different  forms  of  anaemia,  and  in  scurvy. 
The  amount  of  water  is  diminished  in  abundant  transudations,  by  the 
action  of  powerful  laxatives,  in  diarrhoea,  and  especially  in  cholera. 

The  amount  of  2^roteids  in  the  blood  may  be  relatively  increased 
(HYPEiiALBUMixosis)  in  cbolcra  and  after  the  action  of  laxatives.  A 
decrease  in  the  amount  of  proteids  (hypalbuminosis)  occurs  after  direct 
loss  of  proteids  from  the  blood,  as  in  hemorrhage,  albuminuria,  in  evacua- 
tions rich  in  proteid  (dysentery),  copious  formation  of  pus,  anasmia,  etc., 
etc.  The  amount  of  fbrin  is  increased  (hypekinosis)  in  inflammatory 
diseases,  pneumonia,  acute  muscular  rheumatism,  and  erysipelas,  in  which 
the  blood  yields  a  "  ckusta  phlogistica  "  because  it  coagulates  more 
slowly.  The  statements  in  regard  to  the  occurrence  of  a  hyperinosis  in 
scurvy  and  hydrsemia  seems  to  require  further  confirmation.  A  decrease  in 
the  amount  of  fibrin  (hypinosis)  has  not  been  observed  with  certainty  in 
any  disease. 


'  Cited  from  Iloppe-Seyler,  Physiol.  Clicni.,  S.  479. 

*  Viichow,  Gesammelte  Abhaudl.  zur  wisseusch.  Med.,  Bd.  3. 


QUANTITY  OF  FAT  AND  SUGAR  IN   THE  BLOOD.  179 

The  amount  of  fat  in  the  Mood  (lip^mia)  increases,  irrespective  of  the 
increase  after  a  diet  rich  in  fat,  in  drunkards,  in  corpulent  individuals, 
after  fracture  of  the  hones,  and  also  in  diabetes.  In  the  last-mentioned 
case  the  increase  in  fat  depends,  according  to  IIoppe-Seyler,'  upon  defec- 
tive digestion.  V.  jAKSciiMias  observed  volatile  fatty  acids  in  the  blood 
(lipacid.kmia)  in  febrile  diseases,  leucaemia,  and  sometimes  in  diabetes. 

The  amount  of  salts  in  the  blood  is  increased  in  dropsy,  dysentery,  and 
in  cholera  immediately  after  the  first  violent  attack,  but  diminishes  later 
after  the  attack  in  cholera,  in  scurvy,  and  in  inflammatory  diseases. 
According  to  Moraczewski  '  the  quantity  of  chlorine  in  the  blood  is 
increased,  with  a  simultaneous  decrease  in  the  quantity  of  chlorine  in  the 
urine  and  a  chlorine  retention  takes  place.  In  pneumonia  and  nephrites  the 
chlorine  of  the  blood  is  diminished  with  a  simultaneous  decrease  of  chlorine 
in  the  urine.  The  statements  in  regard  to  the  alkalinity  of  the  blood  in 
diseases  are  uncertain. 

H\\Q  quantity  of  glucose  \&  increased  in  diabetes  (mellitaemia).  IIoppe- 
Seyler  found  in  one  case  9  p.  m.  glucose  in  the  blood.  According  to 
Claude  Bernard,*  when  the  quantity  of  glucose  in  the  blood  amounts  to 
3  p.  m.  it  passes  into  the  urine.  The  correctness  of  this  statement  has  been 
disputed  for  some  time,  and  in  fact  we  do  not  know  to  what  extent  the  re- 
ducing power  of  the  blood  is  due  to  the  presence  of  other  bodies  (jecorin). 
According  to  Lepine  and  Barral  and  Kaufmaxn  ^  the  saccharifying 
property  of  the  blood  is  diminished  in  diabetes.  The  quantity  of  tirea  is 
augmented  in  fevers,  also  in  increased  metabolism  of  proteids,  followed  by 
an  increased  urea  formation.  A  further  increase  in  the  amount  of  urea  in 
the  blood  occurs  in  retarded  micturition,  as  in  cholera  as  well  as  in  cholera 
infantum  (K.  Morxek'),  and  in  affections  of  the  kidneys  and  the  urinary 
passages.  After  a  ligature  of  the  ureters  or  after  extirpation  of  the  kidneys 
of  animals  an  accumulation  of  urea  takes  place  in  the  blood.  Uric  acid  is 
found  increased  in  the  blood  in  gout  (Garuod,  Salomon'");  oxalic  acid 
was  also  found  in  the  blood  in  the  same  disease  by  Garrod.  According  to 
V.  Jakscii  fevers  alone  do  not  lead  to  uricacidmmia.  Uric  acid  occurs  in 
relatively  large  quantities,  up  to  0.08  p.  m.,  in  croupous  pneumonia, 
affections  of  the  kidneys,  anajmia,  and  especially  such  conditions  which  lead 

•  Physiol.  Cbem.,  S.  433. 

»  Zeitscbr.  f.  kliu.  Med.,  Bd.  11. 

'  Virchow's  Arch..  Bdd.  139  aud;i46. 

*  Hoppe-Seyler,  Physiol.  Chem.,  S.  430;  Bernard,  Le9ons  sur  le  diab^te.    Paris,  1877. 
'  Lepiue  aud  Barral,  Revue  de  niedecine,  1892  ;  Kaufmann,  Compt.  rend,  de  Sec. 

bid.,  Tome  46. 

«  See  Maly's  Jabrcsber.,  Bd.  17,  S.  453. 

'  Garrod,  Med.  Surg.  Trausactions,  Vols.  31  and  37  ;  Salomon,  Zeitscbr.  f.  physiol. 
Chem.,  Bd.  2. 


180  THE  BLOOD. 

to  the  symptoms  of  dyspnoea.  Xaclein  bases  occur  sometimes  in  very  small 
quantities  (v.  Jaksch). 

Among  the  foreign  bodies  which  are  found  in  the  blood  the  following 
must  be  mentioned  here:  biliaet  acids  and  biliary  pigmexts  (which 
latter  may  occur  under  physiological  conditions  in  a  few  varieties  of  blood) 
in  icteras;  leucix  and  ttrosix  in  acute  atrophy  of  the  liver;  aceton 
especially  in  fevers  (v.  Jaksch  ').  In  melanaemia,  especially  after  continuons 
malarial  fever,  black,  less  often  light  brown  or  yellowish,  grains  of  pigment 
occur  in  the  blood,  which,  according  to  the  generally  received  opinion, 
come  from  the  spleen.  After  poisoning  with  potassium  chlorate,  methse- 
moglobin  is  observed  in  human  and  in  canine  blood  (MAECHAifD  and 
Cahx)  ;  but,  on  the  contrary,  no  formation  of  methgemoglobin  takes  place 
in  the  blood  of  rabbits  (Stokvis  and  Kimmtsee).  A  formation  of  metha^- 
moglobin  may  be  caused  at  the  expense  of  the  hsemoglobin  by  the  inhalation 
of  amvl  nitrite,  as  also  by  the  action  of  a  number  of  other  medicinal  bodies 
(Hatem,  Dittrich,*  and  others). 

The  quantity  of  hlood  is  indeed  somewhat  variable  in.  different  species 
of  animals  and  in  different  conditions  of  the  body;  in  general  we  consider 
the  entire  quantity  of  blood  in  adults  as  about  yV~tV  ^^  ^^®  weight  of  the 
body,  and  in  new-born  infants  about  y^.  Fat  individuals  are  relatively 
poorer  in  blood  than  lean  ones.  During  inanition  the  quantity  of  blood 
decreases  less  quickly  than  the  weight  of  the  body  (PAXUii^),  and  it  may 
therefore  be  also  proportionally  greater  in  starving  individuals  than  in  well- 
fed  ones. 

By  careful  bleeding  the  quantity  of  blood  may  be  considerably  diminished 
without  any  dangerous  symptoms.  The  loss  of  blood  to  ^  of  the  normal 
quantity  has  as  sequence  no  durable  sinking  of  the  blood-pressure  in  the 
arteries;  while  the  smaller  arteries  accommodate  themselves  to  the  small 
quantities  of  blood  by  contracting  (Worm  Muller  *).  A  loss  of  blood  to  one 
third  of  the  quantity  reduces  the  blood-pressure  considerably,  and  a  loss  of 
one  half  of  the  blood  in  adults  is  dangerous  to  life.  The  more  rapid  the 
bleeding  the  more  dangerous  it  is.  N"ew-bom  infants  are  very  sensitive  to 
loss  of  blood,  and  likewise  fat,  old,  and  weak  persons  cannot  stand  much 
loss  of  blood.     "Women  can  stand  loss  of  blood  better  than  men. 

The  quantity  of  blood  may  be  considerably  increased  by  the  injection  of 
blood  from  the  same  species  of  animal  (Paxum,  Laxdois,  Worm  Muller, 
Ponfick).    According  to  Worm  Muller  the  normal  quantity  of  blood  may 

'  Ueber  Acetonurie  und  Diaceturie.     Berlin,  1885, 

»  Marcband,  Virchow's  Arcb.,  Bd.,  77,  and  Arcb.  f.  exp.  Patb.  u.  Pbarm.,  Bd.  22  ; 
Cahn,  ibid.,  Bd.  24  ;  Stokvis,  ibid.,  Bd.  21  ;  Kimmyser,  sec  Muly's  .Jabresber.,  Bd.  14; 
Ilayem,  Compt.  rend.,  Tome  102  ;  Dittricb,  Arcb.  f.  cxp.  Patb.  u.  Pbarm.,  Bd.  29. 

2  Vircbow's  Arcb.,  Bd.  29. 

*  Transfusion  und  Pletbora.     Cbristiania,  1875. 


TRANSFUSION  OF  BLOOD.  181 

indeed  be  increased  to  83<^  without  producing  any  abnormal  conditions  or 
lasting  high  blood-pressure.  An  increase  of  the  quantity  of  blood  to  150j^ 
may  be  directly  dangerous  to  life  ("Worm  Muller).  If  the  quantity  of 
blood  of  an  animal  is  increased  by  transfusion  with  blood  of  the  same  kind 
of  animal,  an  abundant  formation  of  lymph  takes  place.  The  water  in 
excess  is  eliminated  by  the  urine;  and  as  the  proteid  of  the  blood-serum  is 
quickly  decomposed,  while  the  red  blood-corpuscles  are  destro3'ed  much 
more  slowly  (Tschir.few,  Forster,  Tanum,  Worm  INIuller'),  a  polycy- 
themia is  gradually  produced. 

If  blood  of  another  kind  is  transfused,  then  under  certain  conditions, 
according  to  the  quantity  of  blood  introduced,  more  or  less  menacing 
symptoms  occur.  These  appear,  for  instance,  when  the  blood-corpuscles 
of  the  receiver  are  dissolved  easily  by  the  serum  of  the  introduced  blood,  as, 
for  example,  the  blood-corpuscles  of  rabbits  on  transfusion  with  a  different 
kind  of  blood,  or  the  reverse,  when  the  blood-corpuscles  of  the  transfused 
blood  are  dissolved  by  the  blood  of  the  receiver;  for  instance,  when  the 
blood  of  a  dog  is  transfused  with  rabbit's  or  lamb's  blood,  or  the  blood  of  a 
man  with  lamb's  blood  (Laxdois).  Before  dissolving,  the  blood-corpuscles 
may  unite  in  tougli  agglomerated  heaps,  which  clog  up  the  smaller  vessels 
(Landois).  On  the  other  hand,  the  stromata  of  the  dissolved  blood- 
corpuscles  may  also  give  rise  to  an  extensive  intravascular  coagulation, 
causing  death. 

The  transfusion  should  therefore  when  possible  be  made  with  the  blood 
of  the  same  kind  of  animal,  and  for  the  resuscitating  action  of  the  blood  it 
is  immaterial  whether  or  not  it  contains  the  librin  or  the  mother-substance 
of  the  same.  The  action  of  transfused  blood  depends  on  its  blood- 
corpuscles,  and  therefore  defibrinated  blood  acts  just  like  non-defibrinated 
(Panum,  Laxdois). 

The  property  of  blood-serum  of  a  certain  species  of  animals  of  dissolving  or  destroy-- 
ing  the  blood-corpusclLS  of  iinother  has  been  called  the  globidicidal  action  of  the  serum- 
Tlie  bartericid;il  or  so-called  microbiciifal  action  of  the  serum  stands  in  close  connection  to 
the  above.  These  actions  are  connected  with  the  presence  of  certain  enzyme-like  protein 
bodies,  so-called  aUxins.  which  originate  from  the  leucocytes.  As  shown  by  Hoden, 
Hahn,  Camys,  and  Gley,"  blood-senini  acts  destructivelj'  on  certain  enzymes,  such  as 
reunin,  pepsin,  and  trypsin,  but  this  action  is,  according  to  Haun,  not  connected  with 
the  globulicidal  or  bactericidal  action. 

The  quantity  of  blood  in  the  different  organs  depends  essentially  on  the 
activity  of  the  same.     During  work  the  exchange  of  material  in  an  organ 

•  Panum.  Nord.  med.  Ark.,  Bd.  7;  Virchow's  Arch.,  Bd.  63  ;  Landois,  Centralbl. 
f.  d.  med.  Wissensch.,  1875,  and  "Die  Transfusion  des  Blutes,"  Leipzig,  1875;  Worm 
Milller,  "Transfusion  uud  Plethora";  Ponlick,  Virchow's  Arch. ,  Bd.  62  ;  Tschirjew, 
Arbeiten  aus  der  Physiol.  Anstalt  zu  Leipzig,  1874,  S.  292;  Forster,  Zeitschr.  f.  Biologie, 
Bd.  11;  Panum,  Virchow's  Arch.,  Bd.  29. 

■^  Roden,  see  Maly's  Jahresber.,  Bd.  17  ;  Hahn,  Berlin,  klin.  Wochenschr.,  1897,  No. 
23  ;  Camys  and  Gley,  xVrch.  de  Physiol.  (5),  Tome  9. 


182  THE  BLOOD. 

is  more  active  than  when  at  rest,  and  the  increased  metabolism  is  connected 
with  a  more  abundant  flow  of  blood.  Although  the  total  quantity  of  blood 
in  the  body  remains  constant,  the  distribution  of  the  blood  in  the  various 
organs  may  be  different  at  different  times.  As  a  rule,  the  quantity  of  blood 
in  an  organ  can  be  an  approximate  measure  of  the  more  or  less  active 
metabolism  going  on  in  the  same,  and  from  this  point  of  view  the  distribu- 
tion of  the  blood  in  the  different  organs  and  groups  of  organs  is  of  interest. 
According  to  Eanke,'  to  whom  we  are  especially  indebted  for  our  knowl- 
edge of  the  relationship  of  the  activity  of  the  organs  to  the  quantity  of 
blood  contained  therein,  of  the  total  quantity  of  blood  (in  the  rabbit)  about 
one  fourth  comes  to  the  muscles  in  rest,  one  fourth  to  the  heart  and  the  large 
blood-vessels,  one  fourth  to  the  liver,  and  one  fourth  to  the  other  organs. 

'  Die  Blutvertheilung  und  der  Thaiigkeitswechsel  der  Organe.     Leipzig,  1871. 


CHAPTER  VII. 
CHYLE,   LYMPH,    TRANSUDATIONS  AND  EXUDATIONS. 

I.  Chyle  and  Lyinph. 

The  lymph  is  the  mediator  in  the  exchange  of  constituents  between  the 
blood  and  tissues.  The  bodies  necessary  for  the  nutrition  of  the  tissues 
pass  from  the  blood  into  the  lymph,  and  the  tissues  deliver  water,  salts,  and 
products  of  metabolism  to  the  lymph.  The  lymph  therefore  originates 
partly  from  the  blood  and  partly  from  the  tissues.  From  a  purely  theoreti- 
cal standpoint  we  can,  according  to  IIeideniiain,  differentiate  between 
blood-lymph  and  tissue-lymph  according  to  origin.  It  is  impossible  at  the 
present  time  to  completely  separate  what  one  or  the  other  source  supplies. 
Chemically  the  lymph  is  the  same  as  plasma  and  contains,  at  least  to  a  great 
extent,  the  same  bodies.  The  observation  of  Asiier  and  Barbera,'  that 
the  lymph  contains  poisonous  metabolic  products,  does  not  contradict  such 
an  assumption,  as  no  doubt  these  products  are  transferred  to  the  blood  with 
the  lymph.  Although  the  blood  does  not  show  the  same  poisonous  action 
as  the  lymph,  still  this  can  be  explained  by  the  great  dilution  these  bodies 
undergo  in  the  blood,  and  the  difference  between  blood-plasma  and  lymph  is 
no  doubt  of  a  quantitative  nature.  This  difference  consists  chiefly  in  that 
the  lymph  is  poorer  in  proteids.  No  essential  chemical  difference  has  been 
found  between  the  lymph  and  the  chyle  of  starving  animals.  After  fatty 
food  the  chyle  differs  from  the  lymph  in  its  wealth  of  minutely  divided  fat- 
globules,  which  give  it  a  milky  appearance;  hence  the  old  name  "lacteal 
fluid." 

Chyle  and  lymph,  like  the  plasma,  contain  seralhumin,  serghbuliny 
fbrinogen,  and  fibrin-ferment.  The  two  last-mentioned  bodies  occur  only 
in  very  small  amounts;  therefore  the  chyle  and  lymph  coagulate  slowly  (but 
spontaneously)  and  yield  but  little  fibrin.  Like  other  liquids  poor  in  fibrin- 
ferment,  chyle  and  lymph  do  not  at  once  coagulate  completely,  but  repeated 
coagulations  take  place. 

The  extractive  bodies  seem  to  be  the  same  as  in  jilasma.  Sugar  is 
found  in  about  the  same  quantity  as  in  the  blood-serum,  but  in  larger 
quantities  than  in  the  blood;   this  depends  on  the  fact   that  the  blood- 

'  Zeitscbr.  f.  Biologic,  Bd.  36. 

188 


184  CETLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

corpuscles  contain  no  sugar.  The  glycogen  detected  by  Dastre^  in  the 
lymph  occurs  only  in  the  leucocytes.  According  to  Eohmann  and  Bial 
lymph  contains  a  diastatic  enzyme  similar  to  that  in  blood-plasma,  and 
Lepixe  "  has  found  that  the  chyle  of  a  digesting  dog  has  great  glycolytic 
activity.  The  amount  of  tirea  has  been  determined  by  Wurtz  ^  as 
0.12-0.28  p.  m.     The  mineral  todies  appear  to  be  the  same  as  in  plasma. 

As  form-elements  leucocytes  and  red  hlood-corpuscles  are  common  to  both 
chyle  and  lymph.  Chyle  in  fasting  animals  has  the  appearance  of  lymph. 
After  fatty  food  it  is,  on  the  contrary,  milky,  due  partly  to  small  fat- 
globules,  as  in  milk,  and  partly,  to  greatest  extent,  to  finely  divided  fat. 
The  nature  of  the  fat  occurring  in  chyle  is  due  to  the  variety  existing  in 
the  food.  The  disproportionately  greater  part  consists  of  nentral  fat,  and 
even  after  feeding  with  large  (quantities  of  free  fatty  acids  Munk  ^  found 
that  the  cliyle  contained  chiefly  neutral  fat  with  only  small  amounts  of  fatty 
acids  or  soaps. 

The  gases  of  the  chyle  have  not  been  studied,  and  it  seems  that  the 
gases  of  an  entirely  normal  human  lymph  have  not  thus  far  been  investi- 
gated. The  gases  from  dog-lymph  contain  only  traces  of  oxygen  and 
consist/of  37.4-53.1^  CO,  and  1.6^N  calculated  at  0°  C.  and  760  mm. 
mercury.  The  chief  mass  of  the  carbon  dioxide  of  the  lympli  seems  to  be 
firmly  chemically  combined.  Comparative  analyses  of  blood  and  lymph 
have  shown  that  the  lymph  contains  more  carbon  dioxide  than  arterial,  but 
less  than  venous,  blood.  The  tension  of  the  carbon  dioxide  of  lymph  is, 
according  to  Pfluger  and  Strassburg,*  smaller  than  in  venous,  but  greater 
than  in  arterial,  blood. 

The  quantitative  coynposition  of  the  chyle  must  naturally  be  very  variable. 
The  analyses  thus  far  made  refer  only  to  that  mixture  of  chyle  and  lymph 
which  is  obtained  from  the  thoracic  duct.  The  specific  gravity  varies 
between  1.007  and  1.043.  As  example  of  the  composition  of  human  chyle 
we  will  here  give  two  analyses.  The  first  is  by  Owen-Eees,  of  the  chyle 
of  an  executed  person,  and  the  second  by  Hoppe-Seyler,'  of  the  chyle  in 
a  case  of  rupture  of  the  thoracic  duct.  In  the  latter  case  the  fibrin  had 
previously  separated.     The  results  are  in  1000  parts. 

'  Compt.  rend,  de  Soc.  biol.,  Tome  17,  and  Compt.  rend.,  120;  Arch  de  Pliysiol.  (5),  7. 

'  Rijhnmnn  and  Biul,  Pfluger's  Arch.,  Bdd.  52,  53,  and  55;  Lepine,  Compt.  rend., 
Tome  110. 

'  Compt.  rend.,  Tome  49. 

••  Virchow's  Arch.,  Bdd.  80  and  123. 

^  Ilainmarsten,  "Die  Gase  der  Hundelymphe, "  Arbeiteu  aus  d.  physiol.  Anstalt  zu 
Leipzig,  1871  ;  Strassburg,  PflUger's  Arch.,  Bd.  6. 

«  Oweii-Rees,  cited  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  595;  Hoppe-Seyler, 
ibid.,  S.  597. 


COMPOSITION  OF  CHYLE  AND  LYMPH.  185 

No.  1.  No.  2. 

Water 904.8  940.72  water 

Solids 95.2  59.28  solids 

Fibrin traces 

Albumin 70.8  36.67  albumin 

Fat 9.2  7.23  fat 

2.35  soaps 
ro.8:^  lecithin 
T,        .   .  •    1     ]•  mo  !  1.33  cholesterin 

Remaining  organic  bodies      10.8  -j  3  53  .^,^^,^^j  extractives 

[0.58  water  extractives 
y  ,  ..  i  6.80  soluble  salts 

^''''■'^ ^-^  '/O.SSir.solulile  salts 

The  quantity  of  fat  is  very  variable  and  may  be  considerably  increased 
by  partaking  food  rich  in  fats.  I.  ^Iuxk  and  A.  Kosexsteix  '  have  inves- 
tigated the  lymph  or  chyle  obtained  from  a  lymph  fi.stula  at  the  end  of  the 
upper  third  of  the  leg  of  a  girl  18  years  old  and  vreighing  GO  kg.,  and  the 
highest  quantity  of  fat  in  the  chylous  lymph  was  47  p.  m.  after  partaking 
of  fat.  In  the  starvation  lymph  from  the  same  patient  they  found  only 
0.6-2.6  p.  m.  fat.  The  quantity  of  soaps  was  always  small,  and  on  partak- 
ing of  41  gm.  fat  the  quantity  of  soaps  was  only  about  -^  of  the  neutral 
fats. 

A  great  many  analyses  of  chyle  from  animals  have  been  made,  and  they 
chiefly  show  the  fact  that  the  chyle  is  a  liquid  with  a  very  changeable  com- 
position which  stands  closely  related  to  blood-plasma,  bat  with  the  chief 
difference  that  it  contains  more  fat  and  less  solids.  The  reader  is  referred 
to  special  works  for  these  analyses,  as,  for  example,  to  v.  Gorup-Besaxez's 
"  Lehrbnch  der  physiologischen  Chemie,"  4th  edition. 

The  composition  of  the  lymph  is  also  very  changeable,  and  its  specific 
gravity  shows  about  the  same  variation  as  the  chyle.  In  the  following 
analyses,  1  and  2,  made  by  Gubler  and  Quevenxe,  are  the  results 
obtained  from  lymph  from  the  upper  part  of  the  thigh  of  a  woman  aged  39; 
and  3,  made  by  v.  Sciierer,  is  an  analysis  of  lymph  from  the  sac-like 
dilated  lymphatic  vessels  of  the  spermatic  cord.  Xo.  4  was  made  by 
C.  Schmidt,'  the  data  being  obtained  from  lymph  from  the  neck  of  a  colt. 
The  results  are  in  parts  per  1000. 

12  3  4 

Water 939.9  984.8  957.6  955.4 

Solids 60.1  65.2  42.4  44.6 

Fibrin 0.5  0.6                0.4  2.3 

Albumin 42.7  42.8  34.7) 

Fat.  cholesterin,  lecithin 3.8  9.2  )■  35.0 

Extractive  bodies 5.7  4.4  ....) 

Salts 7.3  8.2               7.2  7.5 

»  Virchow's  Arch.,  Bd.  123. 

'  Gubler  and  Quevenne,  cited  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  591  ;  Scherct 
Und.,  S.  591  ;  C.  Schmidt,  ibid.,  S.  592. 


186  CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

The  salts  found  by  C.   Schmidt  iu  the  lymi^h  of  the  horse  has  the 

following  composition,  calculated  in  parts  per  1000  parts  of  the  lymph: 

Sodium  chloride 5.67 

Soda 1.27 

Potash 0.16 

Sulphuric  acid 0.09 

Phosphoric  acid  uuited  with  alkalies , 0.02 

Earthy  phosphates 0.26 

In  the  cases  investigated  by  Munk  and  Kosensteik  the  quantity  of 
solids  in  the  fasting  condition  varied  between  35.7  and  57.2  p.  m.  This 
variation  was  essentially  dependent  upon  the  extent  of  secretion,  so  that  the 
low  amount  coincides  with  a  more  active  secretion,  and  the  reverse  in  the 
other  case.  The  chief  portion  of  the  solids  consisted  of  proteids,  and  the 
relationship  between  globulin  and  albumin  was  as  1  :  2.4  to  4.  The  mineral 
bodies  in  1000  parts  lymph  (chylous)  was:  NaCl  5.83;  ISXCO,  2.17; 
K,HPO,  0.28;  Ca3(P0J,  0.28;  Mg3(P0J,  0.09;  and  Ee(POJ  0.025. 

Under  special  conditions  the  lymph  may  be  so  rich  in  finely  divided  fat 
that  it  appears  like  chyle.  Such  lymph  has  been  investigated  by  Hensen" 
in  a  case  of  lymph  fistula  in  a  ten-year-old  boy,  and  by  Lan"G  '  in  a  case  of 
lympli  fistula  in  the  left  upper  part  of  the  thigh  of  a  girl  of  seventeen. 
The  lymph  investigated  by  Henseit  varied  in  the  quantity  of  fat,  as  an 
average  of  nineteen  analyses,  between  2.8  and  36.9  p.  m.,  while  that  inves- 
tigated by  Lang  contained  24,8  p.  m.  of  fat. 

The  quantity  of  lymph  secreted  must  naturally  change  considerably 
under  various  conditions,  and  we  have  no  means  of  measuring  it.  The 
greatness  of  the  flow  of  lymph  is,  as  Heidenhaik  '  suggests,  no  measure 
of  the  abundance  of  supply  of  nutritive  material  to  the  organs,  and  the 
lymph-tubes  act  according  to  him  as  "  drain-tubes,"  removing  the  excess 
of  fluid  from  the  lymph-fissures  as  soon  as  the  pressure  therein  rises  to  a 
certain  height.  AttemjDts  have  been  made  to  determine  the  quantity  of 
lymph  flowing  in  24  hours  in  the  thoracic  duct  of  animals.  According  to 
Heidexiiain  the  quantity  averages  640  c.c.  for  a  dog  weighing  10  kilos. 

Determinations  of  the  quantity  of  lymj^h  in  man  have  also  been 
attempted.  Noel-Patox  '  obtained  1  c.c.  lymph  per  minute  from  the 
severed  thoracic  duct  of  a  patient  weighing  60  kilos.  The  quantity  in  the 
24  hours  cannot  be  calculated  from  this  amount.  In  the  case  of  Munk  and 
Rosenstein,  1134-1372  gm.  chyle  was  collected  in  12-13  hours  after 
partaking  of  food.  In  the  fasting  condition  or  after  starving  for  18  hours 
they  found  50  to  70  gm.  per  hour,  sometimes  120  gm.  and  above,  especially 
in  the  first  few  hours  after  powerful  muscular  exercise. 

Several  circumstances  have  a  marked  influence  on  the  extent  of  lymph 

'  Henseu,  Pfliiger's  Arch.,  Bd.  10  ;  Lang,  see  Maly's  Jahresber.,  Bd.  4. 
'Pflilger's  Arch.,  Bd.  49. 
^  Jouru.  of  Physiol.,  Vol.  11. 


L  TMPUAOOO  UBS.  187 

secretion.  During  starvation  less  lymph  is  secreted  than  after  partaking 
of  food.  Nasse  '  has  observed  in  dogs  that  the  formation  of  lymph  is 
increased  36^  more  after  feeding  with  meat  than  after  feeding  with 
potatoes,  and  about  54f^  more  tlian  after  24  hours'  deprivation  of  food. 

An  increase  in  the  total  blood-pressure,  as  by  transfusion  of  blood,  also 
especially  on  preventing  the  How  of  blood  by  means  of  ligatures,  causes  an 
increase  in  the  quantity  of  lymph.  According  to  IIeidexhaix,  on  the 
contrary,  a  very  considerable  change  in  the  pre.«8ure  in  the  aorta  causes  only 
a  little  change  in  the  abundance  of  the  lymph-How.  The  quantity  of  lymph 
may  be  raised  by  j^owerful  active  and  passive  movements  of  the  limbs 
(Lesser).  Under  the  action  of  curara  an  increase  of  the  lymph-secretion 
is  observed  (Paschutix,  Lessek'),  and  the  quantity  of  solids  in  the  lymph 
is  also  increased. 

In  the  past  the  formation  of  lymph  was  exi^lained  in  a  purely  physical 
way  by  the  united  action  of  filtration  from  the  blood  and  the  osmosis 
between  the  blood  and  tissue  fluid.  Later  IIeidenhain"  and  Hamburger  * 
ascribe  a  special  activity  to  tlie  capillary  endothelium  in  that  they  take 
part  in  the  formation  of  lymph  in  a  secretory  manner. 

According  to  Heidenhain  there  are  two  different  means  of  inciting 
lymph-flow.  They  are  called  lyniphagogjies.  The  lymphagogues  of  the 
first  series — extracts  of  crab-muscles,  blood-leech,  anodons,  liver  and  intes- 
tine of  dogs,  as  well  as  peptone  and  egg  albumin — cause  an  increased  secre- 
tion of  lymph  without  raising  the  blood-pressure,  and  in  this  way  the 
blood-plasma  becomes  poorer  in  proteids  and  the  lymph  richer  than  before. 
For  the  formation  of  this  lymph,  which  Heidenrain  designates  blood- 
lymph,  we  must  admit  with  him  of  a  special  secretory  activity  of  the 
capillary-wall  endothelium.  According  to  Starling,  on  the  contrary,  the 
constitution  of  the  lymph  is  dependent,  in  these  cases,  upon  an  increased 
formation  under  the  influence  of  these  bodies  of  liver-lymph,  which  is  very 
rich  in  solids.  The  above-mentioned  lymphagogues,  according  to  him,  do 
not  excite  the  endothelium  cells  to  secretion,  but  act  more  likely  as  a  toxic 
irritant,  which  increases  the  permeability  of  the  vascular  wall. 

The  lymphagogues  of  the  second  series,  such  as  sugar,  urea,  sodium 
chloride,  and  other  salts,  also  cause  an  abundant  lymph-formation.  Th^i 
blood,  as  well  as  the  lymph,  thereby  becomes  richer  in  water.  This  increased 
amount  of  water  depends,  according  to  IIeidexiiaix,  upon  an  increased 
delivery  of  water  by  the  tissue-elements,  and  this  lymph  is  chiefly  tissue- 

'  Cited  from  Hoppe-Seyler.  Physiol.  Cbem.,  S.  593. 

'  Lesser,  Arbeiten  aus  der  pbysiol.  Anstalt  zu  Leipzig,  Jabrgang  6  ;  Pascbutin, 
ibid.,  7. 

'  Heidenbaiu,  1.  c. ;  Hamburger,  Zeitscbr.  f.  Biologie,  Bdd.  27  aud  30.  See  especially 
Ziegler's  Beitr.  zur  patb.  u.  zur  allg.  Palbol.,  Bd.  14,  S.  443  ;  also  Du  Bois-Keymond's 
Arch.,  1895  aud  1897. 


188  CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

lymph,  according  to  him.  Diffusion  is  no  doubt  of  great  importance  in 
the  formation  of  this  lymph,  but  the  secretory  activity  of  the  endothelium 
is  also  of  importance  at  least  for  certain  bodies,  such  as  sugar. 

Several  investigators,  among  whom  Starling  and  Cohnstein  ^  must 
be  specially  mentioned,  contest  the  secretion  theory  and  advocate  the 
older  view.  This  question  is  still  disputed,  but  nevertheless  experience 
shows  that  the  physical  forces,  filtration  and  osmosis,  are  not  alone  sufficient 
to  explain  the  formation  of  lymph. 

II.  Transudations  and  Exudations. 

The  serous  membranes  are  normally  kept  moistened  by  liquids  whose 
quantity  is  only  sufficient  in  a  few  instances,  as  in  the  pericardial  cavity 
and  the  subarachnoidal  space,  for  a  complete  chemical  analysis  to  be  made 
of  them.  Under  diseased  conditions  an  abundant  transudation  may  take 
place  from  the  blood  into  the  serous  cavities,  into  the  subcutaneous  tissues, 
or  under  the  epidermis;  and  in  this  way  pathological  transudations  are 
formed.  Such  true  transudations,  which  are  similar  to  lymph,  are- 
generally  poor  in  form-elements  and  leucocytes,  and  yield  only  very  little 
or  almost  no  fibrin,  while  the  inflammatory  transudations,  the  so-called 
exudations,  are  generally  rich  in  leucocytes  and  yielci'  proportionally  more 
fibrin.  As  a  rule,  the  richer  a  transudation  is  in  leucocytes  the  closer  it 
stands  to  pus,  while  when  it  has  a  diminished  quantity  of  leucocytes  it  is 
more  nearly  like  real  transudations  or  lymph. 

It  is  ordinarily  accepted  that  filtration  is  of  the  greatest  importance  in 
the  formation  of  transudations  and  exudations.  The  facts  coincide  with 
this  view,  namely,  that  all  these  fluids  contain  the  salts  and  extractive 
bodies  occurring  in  the  blood-plasma  in  about  the  same  quantity  as  the 
blood-plasma,  while  the  amount  of  proteids  is  habitually  smaller.  While 
the  different  fluids  belonging  to  this  group  have  about  the  same  quantities 
of  salts  and  extractive  bodies,  they  differ  from  each  other  chiefly  in  contain- 
ing differing  quantities  of  proteid  and  form-elements,  as  well  as  varying 
quantities  of  transformation  and  decomposition  products  of  these  latter — 
changed  blood-coloring  matters,  cholesterin,  etc.,  etc. 

It  must  be  apparent  that  the  circulation  and  pressure  conditions  have 
an  essential  influence  on  the  quantity  and  composition  of  the  transudations, 
but  their  action  has  been  little  studied;  one  thing,  however,  is  certain, 
and  that  is  that  the  condition,  as  long  as  the  vascular  wall  is  liealthy,  is 
different  from  when  the  capillary  wall  is  changed. 

'  See  Starling,  Journ.  of  Physiol.,  Vols.  16,  17,  18,  and  19;  Cohnstein,  Virchow's 
Arch.,  Bel.  135,  and  Pfliiger's  Arch.,  Bdd.  59,  60,  62,  and  63.  See  also  Leathes,  Journal 
of  Phy.siol.,  "Vols.  18  and  19  ;  Orlow,  Pfliigers  Arch.,  Bd.  59  ;  Lazarus-Barlow,  Journal 
of  Physiol.,  Vol.  19  ;  Asher  and  Barbera,  Zeitschr.  f.  Biologic,  Bd.  36. 


TRANSUDATIONS  AND  EXUDATIONS.  189 

The  changed  permeability  of  the  capillary  walls  in  disease,  as  suggested 
by  CoHNiiEiM,'  is  a  second  important  factor  in  the  formation  of  transu- 
dations. The  ^circumstance  that  the  greatest  quantity  of  proteid  occnrs 
in  transudations  in  inllammatory  processes,  to  which  is  also  due  the 
abundant  quantity  of  form-elements  in  such  transudations,  has  been 
explained  by  this  hypothesis.  The  greater  quantity  of  proteid  in  the 
transudations  in  formative  irritation  is  in  great  part  explained  by  the  large 
amount  of  destroyed  form- elements.  The  interesting  observation  made  by 
Paijkull,'  that  in  such  cases  in  which  an  inflammatory  irritation  has 
taken  place  the  fluid  contains  nucleoalbumin  (op  nncleoproteids  V),  while 
these  substances  do  not  occur  in  transudations  in  the  absence  of  inflamma- 
tory processes,  can  be  explained  by  the  presence  of  form-elements. 

As  the  secretory  importance  of  the  capillary  endothelium  lias  been  made 
probable  by  the  investigations  of  Heidexhain  and  Hamburger,  it  is 
a  priori  to  be  expected  that  an  abnormal!}'  increased  secretory  activity  of  the 
endothelium  is  a  third  cause  of  transudations.  Certain  observations  of 
Hamburger  in  a  case  of  dropsy,'  in  which  the  transudation  was  probably 
produced  by  the  lymph-exciting  action  of  a  metabolic  product  formed  by  a 
bacterium,  speak  for  the  correctness  of  this  assumption.  Hamburger 
therefore  considers  the  irritation  of  the  endothelium  of  the  capillaries  by 
means  of  a  special  substance  exciting  lymph-flow  and  formed  in  disease  as 
a  third  cause  of  the  transudations.  The  question  whether  this  substance 
acts  in  a  secretory  manner  in  Heidenhain's  sense  or  increases  the  per- 
meability in  Starling's  sense  must  be  proved. 

The  varying  quantities  of  proteid  observed  by  C.  Schmidt^  in  the 
tissue-fluids  in  different  vascular  regions  can  perhaps  be  explained  by  the 
different  condition  of  the  capillary  endothelium.  For  example,  the  amount 
of  proteid  in  the  pericardial,  pleural,  and  peritoneal  fluids  is  con- 
siderably greater  than  in  those  fluids  which  are  found  in  the  sub-arach- 
noidal  space,  in  the  subcutaneous  tissues,  or  in  the  aqueous  humor, 
which  are  poor  in  proteid.  The  condition  of  the  blood  also  greatly  affects 
the  transudations,  for  in  hydraemia  the  amount  of  proteid  in  the  transuda- 
tion is  very  small.  With  the  increase  of  the  age  of  a  transudation,  of  a 
hydrocele  fluid  for  instance,  the  quantity  of  proteid  is  increased,  probably 
by  resorption  of  water,  and  indeed  exceptional  cases  may  occur  in  which 
the  amount  of  proteid,  without  any  previous  hemorrhage,  is  even  greatei 
than  in  the  blood-serum. 

The  proteids  of  transudations  are  chiefly  seralbumin,  serglobulin,  and  a 
little  fibrinogen.     Albumoses  and  peptones  do  not  occur,  with  perhaps  the 

'  Cohnlieim,  Vorlesiinfren  iiber  iillg.  Path.,  2.  Aufl.,  Part  1. 

'  Upsala  Liikarofs.  Forhandl.,  Bil.  27,  and  Maly's  Jahresber.,  Bd.  22. 

*  See  Ziegler's  Beit  rage,  Bd.  14. 

*  Cit.  from  Hoppe-Sey lei's  Physiol.  Chem.,  p.  607. 


190  CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

cerebrospinal  fluid  as  exception.  The  non-inflammatory  transudations  do 
not  as  a  rule  coagulate  spontaneously,  or  very  slowly.  On  the  addition  of 
blood  or  blood-serum  they  coagulate.  Inflammatory  exudations  coagulate 
spontaneously.  Paijkull  has  shown  that  these  often  contain  nucleo- 
albumin.  Mucoid  substances,  which  were  first  observed  by  IlAMMARSTEisr 
in  a  few  cases  of  ascites,  without  complication  with  ovarial  tumors,  seem, 
according  to  Paukull,  to  be  regular  constituents  of  transudations.  The 
relationship  between  globulin  and  seralbumin  varies  very  much  in  different 
cases,  but,  as  Hoffman'H  and  Pigbaud  '  have  shown,  the  variation  is  ia 
each  case  the  same  as  the  blood-serum  of  the  individual. 

The  specific  gravity  runs  rather  parallel  with  the  quantity  of  proteid. 
The  varying  specific  gravity  has  been  suggested  as  a  means  of  differentiation 
between  transudations  and  exudations  by  Keuss,''  as  the  first  often  show  a 
specific  gravity  below  1015-1010,  while  the  others  have  a  specific  gravity 
of  1018  or  above.     This  rule  holds  good  in  many  but  not  in  all  cases. 

The  gases  of  the  transudations  consist  of  carbon  dioxide  besides  small 
amounts  of  nitrogen  and  traces  of  oxygen.  The  tension  of  the  carbon 
dioxide  is  greater  in  the  transudations  than  in  the  blood.  When  mixed 
with  pus  the  amount  of  carbon  dioxide  is  decreased. 

The  extractives  are,  as  above  stated,  the  same  as  in  the  blood- plasma;, 
but  sometimes  extractive  bodies  occur,  such  as  allantoin  in  dropsical  fluids 
(MoscATELLi '),  which  have  not  been  detected  in  the  blood.  Urea  seems 
to  occur  in  very  variable  amounts.  Sugar  also  occurs  in  transudations,  but 
we  do  not  know  to  what  extent  the  reducing  power  is  due,  as  in  blood- 
serum,  to  other  bodies.  A  reducing,  non-fermentable  substance  has  been 
found  by  Pickardt  in  transudations.  The  sugar  is  generally  glucose, 
according  to  Pickardt,^  but  levulose  seems  to  occur  in  several  cases. 
Sarcolactic  acid  has  been  found  by  C.  Kulz  ^  in  the  pericardial  fluid  from 
oxen.  Succiyiic  acid  has  been  found  in  a  few  cases  in  hydrocele  fluids,, 
while  in  other  cases  it  is  entirely  absent.  Leiccin  and  tyrosin  have  been 
found  in  transudations  from  diseased  livers  and  in  pus-like  transudations 
which  have  undergone  decomposition.  Among  other  extractives  found  in 
transudations  we  must  mention  uric  acid.,  xantJtin,  creatin.,  inosit,  and 
pyrocatechin  (?). 

As  above  stated,  irrespective  of  the  varying  number  of  form-elements 

'  Paijkull,  1.  c. ;  Hammarsteu,  Zeitsclir.  f.  physiol.  Clieni. ,  Bd.  15;  Hoffmauu,  Arch, 
f.  exp.  Path.  u.  Pliann.,  Bd.  16  ;  Pigeaud,  see  Maly's  Jahresber. ,  Bd.  16. 

'  Reuss,  Deutscli.  Arch.  f.  kliii.  Med.,  Bd.  28;  see  also  Otto,  Zeltscbr.  f.  Heilkunde, 
Bd.  17. 

*  Zeit.sclir.  f.  pliysiol.  Chcm.,  Bd.  13. 

*  Berl.  kiln.  'Wochcnschr.,  1897.  See  also  Rolmann,  Milucli.  med.  Wochenschr., 
1898. 

"  Zeitsch,  f.  Biologie,  Bd.  33. 


PERICARDIAL  AND  PLEURAL  FLUIDS.  191 

contained  in  the  different  transudations,  the  quantity  of  proteid  is  the  most 
characteristic  chemical  distinction  in  the  composition  of  the  various  trans- 
udations; tlierefore  a  qiumtitative  analysis  is  only  of  iinjjortance  in  so  far 
as  it  considers  the  quantity  of  proteid.  On  this  account,  in  the  following 
quantitative  composition,  chief  stress  will  he  put  on  the  quantity  of  proteid. 
Pericardial  Fluid.  The  quantity  of  tliis  fluid  is  also,  under  certain 
physiological  conditions,  so  large  that  a  sufficient  quantity  for  chemical 
investigation  wtis  obtained  from  a  person  who  had  been  executed.  This 
fluid  is  lemon-yellow  in  color,  somewhat  sticky,  and  yields  more  fibrin  than 
other  transudations.  The  amount  of  solids,  according  to  the  analyses  per- 
formed by  V.  CoRur-BESAXEZ,  Waciismuth,  and  Hoppe-Seyler,'  is 
37.5-44.9  p.  m.,  and  the  amount  of  proteid  is  22.8-24.7  p.m.  The  analysis 
made  by  tiie  author  of  a  fresh  pericardial  fluid  from  a  young  man  who 
had  been  executed  yielded  the  following  results,  calculated  in  1000  parts  by 
weight: 

Water    960.85 

Solids 39.10 

I  Fibriu 0.31 

Proteids 28.60-  Globulin 5.95 

(Albumin  ....  23.34 

Soluble  salts 8.60-iNaCl 7.28 


Insoluble  salts 0.15 

Extractive  bodies 2.00 


Friend  ''  has  found  nearly  the  same  composition  for  a  pericardial  fluid 
from  a  horse,  with  the  exception  that  this  liquid  was  relatively  richer  in 
globulin.  The  ordinary  statement  that  pericardial  fluids  are  richer  in 
fibrinogen  than  other  transudations  is  hardly  based  on  sufficient  proof.  In 
a  case  of  chylopericardium,  which  was  jirobably  due  to  the  rupture  of  a 
chylus  vessel  or  caused  by  a  capillary  exudation  of  chyle  because  of 
stoppage,  IIasebroek  '  found  in  1000  parts  of  the  analyzed  fluid  103. Gl 
parts  solids,  73.71)  albuminous  bodies,  10.77  fat,  3.34  cholesterin,  1.77 
lecithin,  and  9.34  salts. 

The  pleural  fluid  occurs  under  physiological  conditions  in  such  small 
quantities  that  a  chemical  analysis  of  the  same  cannot  be  made.  Under 
pathological  conditions  this  fluid  may  show  very  variable  properties.  In 
certain  cases  it  is  nearly  serous,  in  others  again  sero-fibrinous,  and  in  others 
similar  to  pus.  There  is  a  corresponding  variation  in  the  specific  gravity 
and  the  properties  in  general.  If  a  pus-like  exudation  is  kept  closed  for  a 
long  time  in  the  pleural  cavity,  a  more  or  less  complete  maceration  and 
solution  of  the  pus-corpnscles  is  found  to  take  place.     The  ejected  yellowish- 

'  v.  Goiup-Besauez,  Lelirbuch  d.  physiol.  Clicni..  4.  Aufl.,  S.  401  ;  Wacbsmutb, 
Vlrcbow's  Arcb.,  Bd.  7  ;  Iloppe-Seyler,  Physiol.  Chem.,  S.  605. 

*  Halliburton,  Text-book  of  Cbcm.  Physiol.,  etc.     London,  1891.     P.  347. 
'Zeitschr.  f.  pbysiol.  Chem..  Bd.  12. 


192  CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

brown  or  greenish  flaid  may  then  be  as  rich  in  solids  as  the  blood-serani; 
and  an  abundant  flocculent  precipitate  of  a  nncleoalbumin  (the  j-^^/m  of 
early  writers)  may  be  obtained  on  the  addition  of  acetic  acid.  This  precipi- 
tate is  soluble  with  difficulty  in  an  excess  of  acetic  acid. 

Numerous  analyses,  by  many  investigators,'  of  the  quantitative  composi- 
tion of  pleural  fluids  under  pathological  conditions  are  at  hand.  From 
these  analyses  we  learn  that  in  hydrothorax  the  specific  gravity  is  lower  and 
the  quantity  of  proteid  less  than  in  pleuritis.  In  the  first  case  the  specific 
gravity  is  generally  less  than  1015,  and  the  quantity  of  proteid  10-30 
p.  m.  In  acute  pleuritis  the  specific  gravity  is  generally  higher  than  1020, 
and  the  quantity  of  proteid  30-65  p.  to.  The  quantity  of  fibrinogen, 
which  in  hydrothorax  is  about  0.1  p.m.,  may  amount  to  more  than  1  p.  m. 
in  pleuritis.  In  pleurisy  with  an  abundant  gathering  of  pus  the  specific 
gravity  may  rise  even  to  1030,  according  to  the  observations  of  the  author. 
Tlie  quantity  of  solids  is  often  60-70  p.  m.,  and  may  be  even  more  than 
90-100  p.  m.  (author).  Mucoid  substances  have  also  been  detected  in 
pleural  fluids  by  Paijkull.  Cases  of  chylous  pleurisy  are  also  known;  in 
such  a;  case  Mehu'  found  17.93  p.  m.  fat  and  cholesterin  in  the  fluid. 

The  quantity  of  peritoneal  fluid  is  very  small  under  physiological  condi- 
tions. The  investigations  refer  only  to  the  fluid  under  diseased  conditions 
(dropsical  or  ascitic  fltiid).  The  color,  transparency,  and  consistency  of 
these  may  vary  greatly. 

In  cachectic  conditions  or  a  hydraemic  condition  of  the  blood  the  fluid 
has  little  color,  is  milky,  opalescent,  watery,  does  not  coagulate  spon- 
taneously, has  a  very  low  speciflc  gravity,  1005-1010-1015,  and  is  nearly 
free  from  form-elements.  The  ascitic  fluid  in  portal  stagnation,  or 
generally  in  venous  stagnation,  has  a  low  specific  gravity  and  ordinarily  less 
than  20  p.  m.  proteid,  although  in  certain  cases  the  quantity  of  proteid 
may  rise  to  35  p.  m.  In  carcinomatous  peritonitis  it  may  have  a  cloudy, 
dirty-gray  appearance,  due  to  its  richness  in  form-elements  of  various  kinds. 
The  specific  gravity  is  then  higher,  the  quantity  of  solids  greater,  and  it 
often  coagulates  spontaneously.  In  inflammatory  processes  it  is  straw-  or 
lemon-yellow  in  color,  somewhat  cloudy  or  reddish,  due  to  leucocytes  and 
red  blood-corpuscles,  and  from  great  richness  in  leucocytes  it  may  apppear 
more  like  pus.  It  coagulates  spontaneously  and  may  be  relatively  richer  in 
solids.  It  contains  regularly  30  p.  m.  or  more  proteid  (although  exceptions 
with  less  proteid  occur),  and  may  have  a  specific  gravity  of  1.030  or  above. 
By  rapture  of  a  chylous  vessel  the  dropsical  fluid  may  be  rich  in  very  finely 
emulsified  fat  (chylous  ascites).     In  such  cases  3.86-10.30  p.  m.  fat  has 

'  See  the  works  of  Mehu,  Runeberg,  F.  Hoffmann,  Reuss,  Neuenkircben,  all  of 
■wbicb  are  cited  in  Bernbeim's  paper  in  Vircbow's  Arcb..  Bd.  131,  S.  274.  See  also 
Paijkull,  1.  c,  and  Halliburton's  Text-book,  p.  346. 

'  Arcb.  gen.  de  med.,  1886,  Tome  2,  cited  from  Maly's  Jabresber.,  Bd.  16. 


HYDROCELE  AND  SPERMATOCELE  FLUIDS.  193 

laeen  found  in  the  dropsical  fluid  (CJuinociiet,  IIay'),  and  even  17-43 
p.  m.  has  been  found  by  Minkowski.  By  admixture  of  this  fluid  with 
tlie  fluid  from  an  ovarian  cyst  it  may  sometimes  contain  psendomucin  (see 
Chapter  XIII)-,  "We  also  have  cases  in  which  the  ascitical  fluid  contains 
mucoids  whicii  may  be  precipitated  by  alcohol  after  removal  of  the  proteids 
by  coagulation  at  boiling  temperature.  Such  substances,  which  yield  a 
reducing  substance  on  boiling  with  acids,  have  been  found  by  the  author  in 
tuberculous  peritonitis  and  in  cirrhosis  hepatis  syphilitica  in  men.  Accord- 
ing to  the  investigations  of  Paukull"  these  substances  seem  to  occur  often 
and  perhaps  habitually  in  the  ascitic  fluids. 

As  the  quantity  of  proteid  in  ascitic  fluids  is  dependent  upon  the  same 
•circumstances  as  in  other  transudations  and  exudations,  it  is  sufficient  to 
give  the  following  example  of  the  composition,  taken  from  Bernheim's' 
treatise.     Tiie  results  are  expressed  in  1000  parts  of  the  fluid : 

Max.  Min.  Mean. 

Cirrhosis  of  the  liver 34.5  5.6  9.69  —  21.06 

Bright 's  disease 16.11  10.10  5.6    —10.36 

Tuljerculous  and  idiopathic  peritonitis 55.8  18.72  30.7    — 37.95 

Carciuoraatous  peritouitis 54.20  27.00  35.1    — 58.96 

Urea  has  also  been  found  in  ascitical  fluids,  sometimes  onlj'  as  traces,  sometimes  in 
larger  (luautities  (4  p.  m.  in  albuminuria),  also  uric  acid,  ulldntoiti  in  cirrhosis  of  the 
liver  (iMosoATELLi),  xanthin,  creatin,  cholesterin,  and  svgar. 

Hydrocele  and  Spermatocele  Fluids.  These  fluids  differ  from  each  other 
in  various  ways.  The  liydrocele  fluids  are  generally  colored  light  or  darker 
yellow,  sometimes  brownish  with  a  shade  of  green.  They  have  a  relatively 
higher  specific  gravity,  l.OlG-1.026,  with  a  variable  but  generally  higher 
amount  of  solids,  an  average  of  60  p.  m.  They  sometimes  coagulate 
spontaneously,  sometimes  only  after  the  addition  of  fibrin-ferment  or  blood. 
They  contain  leucocytes  as  chief  form-elements.  Sometimes  they  contain 
smaller  or  larger  amounts  of  cholesterin  crystals. 

The  spermatocele  fluids,  on  the  contrary,  are  as  a  rule  colorless,  thin, 
cloudy  like  water  mixed  with  milk.  They  sometimes  have  an  acid  reaction. 
They  have  a  lower  .specific  gravity,  l.OOG-l.OlO,  a  lower  amount  of  solids — 
an  average  of  about  13  p.  m., — and  do  not  coagulate  either  spontaneously 
or  after  the  addition  of  blood.  They  are,  as  a  rule,  poor  in  proteid  and 
contain  spermatozoa,  cell- detritus,  and  fat-globules  as  form-constituents.  To 
show  the  unequal  composition  of  these  two  kinds  of  fluids  we  will  give  the 
average  results  (calculated  in  parts  per  1000  parts  of  the  fluid)   of   17 


'  Guinochet,  see  Strauss,  Arch,  de  Physiol.,  Tome  18.  See  Maly's  Jahresber.,  Bd. 
16,  S.  475. 

'L.  c. 

'  L.  c.  As  it  was  impossible  to  derive  mean  figures  from  those  given  by  Bernheim, 
the  author  has  given  above  the  maximum  and  minimum  of  the  averages  given  by  him. 


194  CHYLE,  LTMFH,  TRANSUDATIONS  AND  EXUDATIONS. 

analyses  of   lij'drocele  fluids  and  4  of  spermatocele  fluids  made  Ijy  Ham* 

MAKSTEN".' 

Hydrocele.    Spermatocele. 

Water 938.85        986.83 

Solids 61.15  13.17 

Fibriu 0.59  

Globulin 13.25  0.59 

Seralbumin 35.94  1.82 

Eiber  extractive  bodies 4.02  ) 

Soluble  salts 8.60  V       10.76 

Insoluble  salts 0.66  ) 

In  the  hydrocele  fluid  traces  of  urea  aud  a  reducing  substance  have  been  found,  and 
in  a  few  cases  also  succinic  acid  and  inosit.  A  hydrocele  fluid  may,  according  to  Devil- 
lard,'  sometimes  contain  paralbumin  or  metalbumin  (?).  Cases  of  chylous  hydrocele 
are  also  known. 

Cerebro-spinal  Fluid.  The  cerebro-spinal  fluid  is  thin,  water-clear,  of 
low  specific  gravity,  1007-1008.  The  spina  bifida  fluid  is  very  poor  in 
solids,  8-10  p.  m.,  with  only  0.19-1.6  p.  m.  proteid.  The  fluid  of  chronic 
hydrocephalus  is  somewhat  richer  in  solids  (13-19  p.  m.)  and  proteids. 
According  to  Halliburton^  the  proteids  of  the  cerebro-spiual  fluid  is  a 
mixture  of  globulin  and  albuiiioses  /  occasionally  some  peptone  occurs,  and 
more  rarely,  in  special  cases,  seralbumin  appears.  Natyratzki  ^  has  shown 
the  presence  of  glucose  in  the  cerebro-spinal  fluid  from  the  calf  and  man, 
and  even  in  amounts  varying  between  0.46  and  0.56  p.  m.  Halliburton's 
statement  as  to  the  occurrence  of  a  substance  similar  to  pyrocatechin  has 
not  been  substantiated.  Nawratzki  found  988.87  p.  m.  water  aud  11.13 
]).  m.  solids  in  the  cerebro-spinal  fluid  from  the  calf.  Of  the  solids  8.13 
p.m.  was  inorganic,  0.22  p.  m.  proteid,  and  2.79  p.  m.  remaining  organic 
substances.  The  older  statement  that  the  cerebro-spinal  fltiid  differs  from 
the  other  transudations  in  a  greater  wealth  of  potassium  salts  has  not  been 
confirmed  by  recent  investigations  of  YvoN,^  Halliburton,  and  Naw- 
ratzki.  According  to  Cavazzani  °  the  cerebro-spinal  fluid  is  more  alkaline 
and  richer  in  solids  in  the  morning  than  in  the  evening. 

Aqueous  Humor.  This  fluid  is  clear,  alkaline,  and  has  a  specific  gravity 
of  1.003-1.009.  The  amount  of  solids  is  on  an  average  13  p.  m.,  and  the 
amount  of  proteids  only  0.8-1.2  p.  m.  Tlie  proteid  consists  of  sei'idbumin 
and  globulin  and  very  little  fibrinogen.  According  to  Gruenhagen  it 
contains  j^araZac^ic  acid,  another  dextrogyrate  substance,  and  a  reducing 
body  which  is  not  similar  to  glucose  or  dextrin.  Pautz  '  found  urea  and 
sugar  in  the  aqueous  humor  of  oxen. 

'  Upsala  Lakaref.  F5rh.,  Bd.  14,  and  Maly's  Jahresber.,  Bd.  8,  S.  347. 

"^  Bull.  soc.  chim.,  Tome  49,  p.  G17. 

'  Halliburton's  Text-book,  pp.  .355-361. 

<  Zeitschr.  f.  phy.siol.  Chcm.,  Bd.  23. 

'  Journ.  do  Pliarm.  et  de  Cliim.  (4),  Tome  26. 

«  Sec  Maly's  Jahresber.,  Bd.  22,  S.  346. 

■•  Gruenhagen,  Pfluger's  Arch.,  Bd.  43 ;  Pautz,  Zeitschr.  f.  Biologie,  Bd.  31. 


SYNOVIAL    FLUID.  195 

Blister-fluid.  The  coutent  of  lilisters  caused  by  burns,  and  of  vesicator 
blisters  ami  the  blisters  of  the  peiiiphiyus  chroniciis,  is  generally  a  fluid 
rich  in  solids  and  proteids  (40-05  p.  ni.).  This  is  especially  true  of  the 
contents  of  ve^catory  blisters.  In  a  burn-blister  K.  Mounek'  found  50.31 
p.  ni.  proteids,  among  which  was  13.59  p.  m.  globulin  and  0.11  ji.  m. 
fibrin.  Tiie  fluid  contains  a  substance  whicli  reduces  copper  oxide  but  no 
pyrocatechin.     Tiie  fluid  of  the  jteniphigus  is  alkaline  in  reaction. 

The  fluid  of  subcutaneous  oedema.  This  is,  as  a  rule,  very  poor  in 
solids,  purely  serous,  does  not  contain  fibrinogen,  and  has  a  specific  gravity 
of  1.005-1.013.  The  quantity  of  proteids  is  in  most  cases  lower  than  10 
p.  m., — according  to  Hoffmann  1-8  p.  m., — and  in  serious  affections  of 
the  kidneys,  generally  with  amyloid  degeneration,  less  than  1  p.  m.  has 
been  shown  (Hoffmann').  The  oedema  fluid  also  habitually  contains 
tirea,  1-2  p.  m.,  and  also  sugar. 

The  FLUID  OF  THE  TAPEWORM  cyst  IS  related  to  the  transudations  poor  in  proteids. 
It  is  tljiu  and  colorless,  and  has  a  specific  gravity  of  1.00.5-1.015.  'i'he  quantity  of  solids 
is  14-20  p.  ni.  The  chemical  constituents  are  xugai'  (2.5  p.  m.).  itiudt,  traces  of  w/vr/, 
creatin,  .succiiric  arid,  and  salts  (8.B-9.7  p.  m.).  Proteids  are  only  found  in  traces,  and 
then  only  after  au  inflamn\atory  irritation.  In  the  last-mentioned  case  7.  p.  m.  proteids 
have  heeu  found  in  the  fluid. 

The  Synovial  Fluid  and  Fluid  in  Synovial  Cavities  around  Joints,  etc. 

The  synovia  is  hardly  a  transudation,  but  it  is  often  treated  as  an  appendix 
to  the  transudations. 

The  synovia  is  an  alkaline,  sticky,  fibrous,  yellowish  fluid  wliich  is 
cloudy,  from  tiie  presence  of  cell-nuclei  and  remains  of  destroyed  cells,  but 
is  also  sometimes  clear.  It  contains  also,  besides  proteids  and  salts,  a  sub- 
stance similar  to  mucin  in  physical  properties.  The  nature  of  this  mucin- 
like  constituent  of  physiological  synovial  fluids  has  not  been  determined. 
Hammarstex  has  found  a  mucin-like  substance  in  pathological  synovial 
fluid,  but  it  was  not  true  mucin.  It  acts  like  a  nucleoalbumin  or  a 
uucleoproteid,  and  gave  uo  reducing  substance  when  boiled  with  acid. 
Salkowski  '  also  found  a  mucin-like  substance  in  a  pathological  synovial, 
fluid,  whicli  was  neither  mucin  nor  nucleoalbumin.  lie  called  the  sub- 
stance "  si/novin.'*^ 

The  composition  of  synovia  is  not  constant,  but  varies  in  rest  and  in 
motion.  In  the  last-mentioned  case  the  quantity  of  fluid  is  less,  but  the 
amount  of  the  mucin-like  body,  proteids,  and  of  the  extractive  bodies  is 
greater,  while  the  quantity  of  salts  is  diminished.  This  may  be  seen  from 
the  following  analyses  by  Frerichs.*    The  figures  represent  parts  per  1000. 

'  Skaud   Arch.  f.  Pliysiol.,  Bd.  5. 

«  Deutscli.  Arch.  f.  klin.  Med  ,  Bd.  44. 

2  Hammarslcii,  Maly's  .Jahresber.,  Bd.  12;  Salkowski,  Virchow's  Arch.,  Bd.  131. 

••  Wairiier's  HandwOrterbuch.  Bd.  3.  Abth.  1.  S.  463. 


196  CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

I.  Synovia  from  II.  Synovia  from 

a  Stall-fed  Ox.  a  Field-fed  Ox. 

Water 969.9  948.5 

Solids 30.1  51.5 

Mucia-like  body 3.4  5.6 

Albumin  and  extractives 15.7  35.1 

Fat 0.6  0.7 

Salts 11.3  9.9 

The  synovia  of  new-born  babes  corresponds  to  that  of  resting  animals. 

The  fluid  of  the  bnrsas  mucosse,  as  also  the  fluid  in  the  synovial  cavities 

around  Joints,  etc.,  is  similar  to  synovia  from  a  qualitative  standpoint. 

III.  Pus. 

Pus  is  a  yellowish-gray  or  yellowish-green,  creamy  mass  of  a  faint  odor 
and  an  unsavory,  sweetish  taste.  It  consists  of  a  fluid,  the  pus-serum,  in 
which  solid  particles,  the  pus-cells,  swim.  The  number  of  these  cells  varies 
so  considerably  that  the  pus  may  at  one  time  be  thin  and  at  another  time 
so  thick  that  it  scarcely  contains  a  drop  of  serum.  The  specific  gravity, 
therefore,  may  also  greatly  vary,  namely,  between  1.020  and  1.040,  but 
ordinarily  it  is  1.031-1.033.  The  reaction  of  fresh  pus  is  generally  alkaline, 
but  it/may  become  neutral  or  acid  from  a  decomposition  in  which  fatty 
acids,^  glycero-phosphoric  acid,  and  also  lactic  acid  are  formed.  It  may 
become  strongly  alkaline  when  putrefaction  occurs  with  the  formation  of 
ammonia. 

In  the  chemical  investigation  of  pus  the  pus-serum  and  the  pus-corpus- 
cles must  be  studied  separately. 

Pus-serum.  Pus  does  not  coagulate  spontaneously  nor  after  the  addition 
of  defibrinated  blood.  The-fluid  in  which  the  pus-corpuscles  are  suspended 
is  not  to  be  compared  with  the  plasma,  but  rather  with  the  serum.  The 
pns-serum  is  pale  yellow,  yellowish  green,  or  brownish  yellow,  and  has  an 
alkaline  reaction.  It  contains,  for  the  most  part,  the  same  constituents  as 
the  blood-serum;  but  sometimes  besides  these — when,  for  instance,  the  pus 
has  remained  in  the  body  for  a  long  time — it  contains  a  nucleoalbumin  or  a 
nucleoproteid  which  is  precipitated  by  acetic  acid  and  soluble  with  great 
difficulty  in  an  excess  of  the  acid  {pyin  of  the  older  authors).  This  nucleo- 
albumin seems  to  be  formed  from  the  hyaline  substance  of  the  pus-cells  by 
maceration.  The  pus-serum  contains,  moreover,  at  least  in  many  cases,  no 
fibrin-ferment.  According  to  the  analyses  of  Hoppe-Seyler  '  the  pus- 
serum  contains  in  1000  parts: 

I.  II. 

Water 913.7  905.65 

Solids 86.3  94.35 

Proteids 63  23  77.21 

Lecithin 1.50  0.56 

Fat 0.26  0.29 

Cholesterin 0.53  0.87 

Alcohol  extractives 1.52  0.73 

Water  extractives 11.53  6.92 

Inorganic  salts 7.73  7.77 

'  Med.-chem.  Untersuch..  S.  490. 


PUS.  V31 

The  ash  of  pus-serum  bas  tbe  follo-wiug  composition,  calculated  to  1000  parts  of  the 
serum : 

1.  II. 

NaCl.." 5.22  5.39 

Na,S04 0.40  0.31 

Na,HP04 (^98  0.46 

Na.COa 0.49  1.13 

C!i3(P()4), 0.49  0.31 

Mg,(PU4)a 0.19  0.13 

PO4  (in  excess) .05 

The  pus-corpuscles  are  generally  thonght  to  consist  in  great  part  of 
emigrated  white  blood-corpascles  (emigration  hypothesis),  and  their  chemi- 
cal properties  have  therefore  been  given  above.  We  consider  the  molecular 
grains,  fat-globules,  and  red  blood-corpuscles  rather  as  casual  form-elements. 

The  pus-cells  may  be  separated  from  the  serum  by  centrifugal  force,  or 
by  decantatiou  directly  or  after  dilution  with  a  solution  of  sodium  sulphate 
in  water  (1  vol.  saturated  sodium-sulphate  solution  and  9  vols,  water),  and 
then  washed  by  this  same  solution  in  the  same  manner  as  the  blood- 
corpuscles. 

The  chief  constituents  of  the  pus-corpuscles  are  albuminous  bodies  of 
which  the  largest  proportion  seems  to  be  a  nucleoproteid  which  is  insoluble 
in  water  and  which  expands  into  a  tough,  slimy  mass  when  treated  with  a 
10^  common-salt  solution.  This  proteid  substance,  which  is  sohible  in 
alkali  but  quickly  changed  thereby,  is  called  Rovidas's  hyaline  snhsfance, 
and  the  property  of  the  pus  of  being  converted  into  a  slime-like  mass  by  a 
solution  of  common  salt  depends  on  this  substance.  Besides  this  substance 
we  find  in  the  pus-cells  also  an  albuminous  body  which  coagulates  at 
48-49°  C,  as  well  as  serglohulin  (?),  seralbumin,  a  substance  similar  to 
coagulated  proteid  (Mieschek),  and  lastly  i:)epione  or  albumose  (IIof- 
MEISTEK  '). 

"We  also  find  in  the  protoplasm  of  the  pus-cells,  besides  the  proteids, 
lecithin,  cholesterin,  xanthin  bodies,  fat,  and  soaps.  Hoppe-Seyler  has 
found  cerebrin,  a  decomposition  product  of  a  protagon-like  substance,  in 
pus  (see  Chapter  XII).  Kossel  and  Freytag  '  have  isolated  from  jius  two 
substances,  pt/osin  and  jin/ogenin,  which  belong  to  the  cerebrin  grouj")  (see 
Chapter  XII).  Hoppe-Seyler'  claims  that  glycogen  appears  only  in  the 
living,  contractile  white  blood-cells  and  not  in  the  dead  pus-corjiuscles. 
Several  other  investigators  have  nevertheless  found  glycogen  in  pus.  The 
cell-nucleus  contains  nuclcin  and  nucleoproteids. 

The  mineral  constituents  of  the  pus-corpuscles  are  jiotassium,  sodium, 
calcium,  magnesium,  and  iron.  A  part  of  the  alkalies  exists  as  chlorides, 
and  the  remainder,  as  well  as  the  other  bases,  exists  as  phosphates. 

'  Miescber  in  Hoppe-Seyler's  Med.-cbem.  Untersucb.,  S.  441  ;  Ilofmeister,  Zeitscbr. 
f.  pbysiol.  Cbem  ,  Bd.  4. 
•^  Ibid.,  B(l.  17,  S.  452. 
■■'  Hoppe-Soyler,  Physiol    Cbem.,  S.  790. 


198  CUTLE,  LYMPIl,   TRANSUDATIONS  AND  EXUDATIONS. 

The   quantitative  compositiou  of   the   pus-cells   from    the   analyses   of 
Hoppe-Seyler  is  as  follows,  in  parts  per  1000  of  the  dried  substance: 

I.  II.  . 

Proteids 137. 62  ) 

Nuclein 342.57  U85.85        673.69 

Insoluble  bodies 205.66  ) 

Lecitbiii )  11000  75.64 

Fat \  ^^^-^^  75.00 

Cholesterin 74.00  72.83 


Cerebrin 51.99^ 


102.84 


Extractive  bodies 44.83  f 

MINERAL    SUBSTANCES  IN   1000   PARTS   OF   THE   DRIED   SUBSTANCE. 

NaCl 4.35 

Ca3{P04)o 2.05 

Mir3iP04)3 1. 18 

FePO, 1.06 

PO4 9.16 

Na 0.68 

K traces  (?) 

MiESCHER  has  obtained  other  results  for  the  alkali  combinations,  namely  :  potassium 
phosphate  12,  sodium  phosphate  6.1,  earthy  phosphate  and  iron  phosphate  4.2,  sodium 
chloride  1.4,  and  phosphoric  acid  combined  with  organic  substances  3.14-2.03  p.  m. 

In  pus  from  congested  abscesses  which  have  stagnated  for  some  time  we 
find  peptone.,  leucin,  and  tyrosin,  iree  fatty  acids,  and  volatile  fatty  acids, 
snch  as  formic  acid,  butyric  acid,  valerianic  acid.  We  also  sometimes  find 
chondrin  (9)  and  glutin  (?),  iirea,  glucose  (in  diabetes),  Mle-pigments  and 
tile-acids  (in  catarrhal  icterus). 

As  more  specific  but  not  constant  constituents  of  the  pus  we  must 
mention  the  following :  pyin,  which  seems  to  be  a  nucleoalbumin  or  nucleo- 
proteid  precipitable  by  acetic  acid,  and  also  pyinic  acid  and  chJorrliodinic 
acid.,  which  have  been  so  little  studied  that  they  cannot  be  more  fully 
treated  here. 

In  many  cases  a  blue,  less  rarely  a  green,  color  has  been  observed  in  the 
pns.  This  depends  on  the  presence  of  a  variety  of  vibrios  (Lucke)  from 
which  FoRDOS  and  Lucke  '  have  isolated  a  crystalline  bine  pigment, 
pyocyanin,  and  a  yellow  pigment,  piyoxa7ithose. 

Appendix. 

Lymphatic  Glands,  Spleen,  etc. 

The  Lymphatic  Glands.  The  cells  of  the  lymphatic  glands  are  found  to 
contain  the  protein  substances  occurring  generally  in  cells  (Chapter  Y, 
pp.  101  and  102).  Albumoses  and  peptones  may  also  occur  as  jjroducts  of  a 
post-mortem  decomposition.  Besides  the  other  ordinary  tissue  constituents, 
finch  as  collagen,  reticulin,  elastin,  and  nuclein,  we  find  in  the  lymphatic 
glands  also  cholesterin,  fat,  glycogen,  sarcolactic  acid,  omnthin  bodies,  and 

*  Fordos,  Compt.  rend..  Tomes  51  and  56 ;  Liicke,  Arch.  f.  klin.  Chirurg.,  Bd.  3. 


SPLEEN.  199 

lenci)i.  In  the  inguinal  glands  of  an  old  woman  Oidtmanx  '  found  714.32 
]).  ni.  water,  284.5  p.  m.  organic  and  I.IG  p.  ni.  inorganic  substances. 

The  Spleen.  The  pnlp  of  the  spleen  cannot  be  freed  from  blood.  The 
mass  which  is  separated  from  the  spleen  capsule  and  the  structural  tissue 
bj  pressure  and  which  ordinarily  serves  as  material  for  chemical  investiga- 
tions is  therefore  a  mixture  of  blood  and  spleen  constituents.  For  this 
reason  the  albuminous  bodies  of  the  spleen  are  little  known.  As  character- 
istic coustitaents  we  have  albuminates  containing  iroji,  and  especially  a 
protein  substance  which  does  not  coagulate  on  boiling,  and  which  is  pre- 
cipitated by  acetic  acid  and  yields  an  ash  containing  much  phosphoric  acid 
and  iron  oxide. ^ 

The  pulp  of  the  spleen,  when  fresh,  has  au  alkaline  reaction,  but 
quickly  turns  acid,  due  partly  to  the  formation  of  free  paraladic  acid  and 
partly  jierhaps  to  ghjcero-])lios2^horic  acid.  Besides  these  two  acids  there 
have  been  found  in  the  spleen  also  volatile  fatty  acids,  as  formic,  acetic, 
and  butyric  acids,  as  well  as  succinic  acid,  neutral  fats,  cliolesterin,  traces 
of  leucin,  inosit  (in  ox-spleen),  scyUit,  a  body  related  to  inosit  (in  the 
spleen  of  plagiostoma),  glycogen  (in  dog-spleen),  uric  acid,  xanthin  bodies, 
and  jecorin  (Baldi  '). 

Among  the  constituents  of  the  spleen  the  deposit  rich  in  iron,  which 
consists  of  ferruginous  granules  or  conglomerate  masses  of  them,  and  closely 
studied  by  Xasse,  is  of  special  interest.  This  deposit  does  not  occur  to 
the  same  extent  in  the  spleen  of  all  animals.  It  is  found  especially 
abundant  in  the  spleen  of  the  horse.  Xasse  *  on  analyzing  the  grains 
(from  the  spleen  of  a  horse)  obtained  840-630  p.  m.  organic  and  160-370 
p.  m.  inorganic  substances.  These  last  consisted  of  566-72G  p.  m.  Fe„0, , 
205-388  p.  m.  Vfi^ ,  and  57  p.  m.  earths.  The  organic  substances  con- 
sisted chiefly  of  proteids  (660-800  p.  m.),  nuclein,  52  p.  m.  (maximum),  a 
yellow  coloring  matter,  extractive  bodies,  fat,  cholesterin,  and  lecithin. 

In  regard  to  the  mineral  constituents  it  is  to  be  observed  that  the 
amount  of  sodium  and  phosphoric  acid  is  smaller  than  that  of  potassium 
and  chlorine.  The  amount  of  iron  in  new-born  and  young  animals  is  small 
(Lapicque,  Kruger,  and  Pernou),  in  adults  more  appreciable,  and  in  old 
animals  sometimes  very  considerable.  Xasse  found  nearly  50  p.  m.  iron 
in  the  dried  pulp  of  the  spleen  of  an  old  horse.  Guillemonat  and 
Lapicque  '   have   determined   the  iron   in   man.     They   find    no   regular 

'  V.  Gorup-Besanez,  Lehrbucb,  4.  Aufl.  S.  732. 

^  Ibid.,  717. 

'  Du  Bois-Reymond's  Arch.,  1887,  Suppl. 

*  Maly's  Jahresber.,  Bd.  19,  S.  315. 

'Lapicque,  ibid.,  Bd.  20;  Lapicque  and  Guillemonat,  Compt.  rend,  de  Soc.  biol.. 
Tome  48,  and  Arch,  de  Physiol.  (5),  Tome  8  ;  Krliger  and  Pernou,  Zeitschr,  f.  Biologic. 
Bd.  27;  Nasse,  cited  from  Hoppe-Seyler,  Pliysiol.  Chem.,  S.  720. 


200  GH7LE.  L7MPH,  TRANSUDATIONS  AND  EXUDATIONS. 

increase  with  growth,  but  in  most  cases  0.17-0.39  ^.  m.  (after  subtracting; 
the  blood-iron)  calculated  on  the  fresh  substance.  A  remarkably  high 
amount  of  iron  is  not  dependent  upon  old  age,  but  is  a  residue  from 
chronic  diseases. 

The  quantitative  analyses  of  the  human  spleen  by  Oidtmann  give  the 
following  results:  In  men  he  found  750-694  p.  m.  water  and  350-306 
p.  m.  solids.  In  that  of  a  woman  he  found  774.8  p.  m.  water  and  225.3 
p.  m.  solids.  The  quantity  of  inorganic  bodies  was  in  men  4.9-7.4  p.  m., 
and  in  women  9.5  p.  m. 

In  regard  to  the  pathological  processes  going  on  in  the  spleen  we  must 
specially  recall  the  abundant  re-formation  of  leucocytes  in  leucseraia  and 
the  appearance  of  amyloid  substance  (see  page  48). 

The  physiological  functions  of  the  spleen  are  little  known  with  the 
exception  of  its  importance  in  the  formation  of  leucocytes.  Some  consider 
the  spleen  as  an  organ  for  the  dissolution  of  the  red  blood-corpuscles,  and 
the  occurrence  of  the  above-mentioned  deposit  rich  in  iron  seems  to  confirm 
this  view.  The  spleen  has  also  been  claimed  to  play  a  certain  part  in 
digestion.  This  organ  is  claimed  by  Schiff,  Heezen,  G-achet  and 
Pachon  to  be  of  importance  in  the  production  of  trypsin  in  the  pancreas. 
The  statements  on  this  question  are  still  disputed  (Heiden^hain",  Ewald'). 

An  increase  in  the  quantity  of  uric  acid  eliminated  has  been  observed 
by  many  investigators  (see  Chapter  XV)  in  lineal  leucaemia,  while  the 
reverse  has  been  observed  under  the  influence  of  quinin  in  large  doses,  which 
produces  an  enlargement  of  the  spleen.  We  have  here  a  rather  positive 
proof  that  there  is  a  close  relationship  between  the  spleen  and  the  formation 
of  uric  acid.  This  relationship  has  lately  been  studied  by  Horbaczewski. 
He  has  shown  that  when  the  spleen-pulp  and  blood  of  calves  are  allowed  to 
act  on  each  other,  under  certain  conditions  and  temperature,  in  the  pres- 
ence of  air,  large  quantities  of  uric  acid  are  formed.  Under  other  condi- 
tions he  obtained  from  the  spleen-pulp  only  xanthin  bodies  with  no  or  very 
little  uric  acid.  Horbaczewski'^  has  also  shown  that  the  uric  acid 
originates  from  the  nucleins  of  the  spleen,  which  yield  nric  acid  and  xanthin 
bodies  according  to  the  experimental  conditions. 

The  spleen  has  the  same  property  as  the  liver  of  retaining  foreign 
bodies,  metals  and  metalloids. 

The  Thymus,  Besides  protein  substances  mentioned  in  Chapter  V  and 
bodies  belonging  to  the  connective-tissue  group,  we  find  small  quantities  of 

>  Schiff,  cited  by  Heizeii,  Pfluger's  Arch.,  Bd.  30,  8.  295  and  308,  and  Maly's 
Jahresber.,  Bd.  18;  Gachet  and  Pachon,  Arch,  de  Physiol.  (5),  Tome  10;  Heidenhain 
in  Herrmann's  Handb.  d.  Physiol.,  Bd.  5,  Absonderungsvorgange,  S.  206  ;  Ewald,  Ver- 
handl.  d.  physiol.  Gescllsch.  in  Berlin,  1878. 

>  Monatshefte  f.  Chem.,  Bd.  10,  and  Wlen,  Sitzungsber,  Math.  Nat.  Klasse,  Bd.  100,. 
Abth.  3. 


THYROID  OLAND.  201 

/a/,  leucin^  succinic  acid,  lactic  acid,  and  sugar ^  and  traces  of  iodothyrin. 
The  large  quantity  of  ranthin  bodies,  chiefly  adenin,  is  remarkaljle — 1,79 
p.  m.  in  the  fresli  gland,  or  19.19  p.  m.  in  tlie  dried  substance  (KossEL 
and  Sciiindler).  Lilienfeld  has  found  inosit  &i\d  protagon  in  the  cells 
of  the  tliymus.  The  quantitative  composition  of  the  lympliocytes  of  the 
th}nius  of  a  calf  is,  according  to  Lilieni'eld's  '  analysis,  us  follows.  The 
results  are  given  in  1000  parts  of  the  dried  substance. 

Proleids 17.6 

Leiiconuclein  687.9 

Histon 86.7 

Lecitbiu  75.1 

Fat 40.2 

Choleslerin 44.0 

Glycogen 8.0 

The  dried  substance  of  the  leucocytes  amounted  to  an  average  of  114.9 
p.  m.  Potassium  and  phosphoric  acid  are  prominent  mineral  constituents. 
LiLiEXEELi)  found  KIf,PO^  amongst  the  bodies  soluble  in  alcohol. 
Oidtmaxn'  found  807. OG  p.  m.  water,  192.74  p.  m.  organic  and  0.2  p.  m. 
inorganic  substances  in  the  gland  of  a  child  two  weeks  old. 

The  Thyroid  Gland.  The  chemical  constituents  of  this  gland  are  little 
known.  Bubxow  has  obtained  a  protein  substance  called  by  him  "  tliyreo- 
proteine,^^  by  extracting  the  gland  with  common-salt  solution  or  by  very 
dilute  caustic  potash.  This  body  has  about  the  same  amount  of  nitrogen, 
but  smaller  amounts  of  carbon  and  hydrogen,  than  the  proteids  in  general. 
The  fluid  found  in  the  vesicle  sometimes  contains  a  mucin-like  substance 
which  is  precipitated  by  an  excess  of  acetic  acid.  Gourlay  '  could  not 
find  any  mucin  but  only  a  nucleoalbumin  in  the  thyroid  gland  of  oxen. 
Besides  these,  other  substances  have  been  found  in  the  extract  of  the 
glands,  such  as  leucin,  Ta7ithin,  hypoarinthi7i,  iodothyrin,  lactic  and  suc- 
cinic acids.  OiDTMAKX^  found  in  the  thyroid  gland  of  an  old  woman 
822.4  p.  m.  water,  17G.7  p.  m.  organic  and  0.9  p.  m.  inorganic  substances. 
lie  found  772. 1  p.  m.  water,  223.4  p.  m.  organic  and  4.5  p.  m.  inorganic- 
substances  in  an  infant  two  weeks  old. 

R.  HrxcHiNSON "  has  determined  the  amount  of  iodine  in  the  protein 
substance,  called  by  him  colloid,  obtained  by  precipitating  the  watery,  salty 
or  faintly  alkaline  extract  of  the  thyroid  (of  sheep  or  calf)  by  acetic  acid 
and  found  0.309^  iodine  in  the  dried  substance.  On  digesting  this  colloid 
with  pepsin  he  obtained  a  protein-free  residue  with  3.69^  iodine,  from 
which  iodothyrin  could  be  extracted  by  boiling  alcohol.     Besides  this  he 


'  Kosscl  and  Scliindler,  Zeitsclir.  f.  pliysiol.  Cliem.,  Bd.  13;  Lilienfeld,  ihiO.,  Bd.  18. 

'  Cited  from  v.  Goruii-Besanez,  Lehrb.  d.  pbysiol.  Chcui.,  4.  Aufl.,  S.  732. 

»  Bubiiow,  Zeitsclir.  f.  pbysiol.  Cbem.,  Bd.  8;  Gourlay,  Journal  of  Physiol,  Vol.  16., 

4  L.  c,  S.  732. 

'  Journal  of  Pbysiol.,  Vol.  23. 


202  CUYLE,  LYMPH,   TRANSUDATIONS  AND   EXUDATIONS. 

obtained  in  solution  an  albnmose  with  0.318^  iodine  and  pej^tone,  which 
was  nearly  iodine-free.  Only  the  albumose  containing  iodine  was  found 
active  in  a  case  of  myxoedema,  but  not  the  peptone. 

Those  substances  which  stand  in  close  relationship  to  the  functions  of 
the  gland  are  of  special  interest. 

The  complete  extirpation,  as  also  the  pathological  destruction,  of  the 
thyroid  gland  causes  great  disturbances,  ending  finally  in  death.  In  dogs, 
after  the  total  extirpation  a  disturbance  of  the  nervous  and  muscular  system 
occurs,  such  as  trembling  and  cramps,  and  death  generally  supervenes  shortly 
after,  most  often  during  an  attack  of  cramps.'  In  human  beings  different 
disturbances  appear,  such  as  nervous  symptoms,  diminished  intelligence, 
dryness  of  the  skin,  falling  out  of  the  hair,  and,  on  the  whole,  those 
symptoms  which  are  included  under  the  name  cachexia  thyreopriva,  and 
death  follows  gradually.  Among  these  symptoms  we  must  mention  the 
peculiar  slimy  infiltration  and  extuberance  of  the  connective  tissue.  It  has 
been  proved  that  the  destructive  action  of  the  removal  of  the  thyroid  can 
be  counteracted  by  the  artificial  introduction  of  extracts  of  the  thyroid 
gland  in/to  the  body,  and  even  by  feeding  with  the  substance  of  the  gland. 
From  this  we  conclude  that  specifically  acting  bodies  must  be  produced 
in  the  thyroid  gland,  which  when  absent  bring  about  in  some  way  or 
another  the  above-mentioned  disturbances.  On  the  other  hand  it  has  been 
observed  on  administering  too  large  quantities  of  gland  substance  that 
threatening  symptoms  and  disturbances  occur  in  man  as  well  as  in  animals.. 
From  a  physiologico-chemical  standpoint  the  diseased,  increased  destruction 
of  body  proteid,  occurring  on  continuous  feeding  with  thyroid  preparations, 
is  of  the  greatest  importance.  From  this  it  seems  to  follow  that  the  specific 
constituents  of  the  gland,  when  administered  in  excess,  may  have  an 
injurious  action. 

S.  Fraxkel'  has  isolated  a  crystalline  base  called  thy reo antitoxin^ 
which  is  soluble  in  alcohol  and  precipitable  by  potassium-mercuric  iodide 
and  which  he  considers  as  the  active  body.  Drechsel  and  Kocher' 
hare  found  two  bases  in  the  gland,  one  of  which  is  probably  identical 
with  Fraxkel's  base.  Frankel's  base  is  especially  active  against 
cramps.  According  to  Xotkix  *  the  specifically  active  substance  is  a 
protein  substance,  called  by  him  thyreoproteid,  while  according  to  Bai- 
MAXX  and  Koos '  the  only  active  body  is  iodothyrin. 

'  Tlie  divergent  sUitements  iis  to  the  necessity  of  the  thyroid  gland  can  be  found  in 
H.  Miink,  Viichow's  Arch.,  Bd.  150. 

2  Friinkel,  Wien.  mad.  Blatter,  1895  and  1896. 

2  Centralbl.  f.  Physiol.,  Bd.  9,  S.  705. 

*  Wien.  med.  "VVochenschr.,  1895,  and  Virchow's  Arch.,  Bd.  144.  Supplement,  S. 
224. 

'  Zeitschr.  f.  physiol.  Chein.,  Bdd.  21  and  22,  also  Baumaun,  Munch,  med.  Wochen- 
schr.,  1896;  Baumaun  and  Goldmauu,  ibid.;  TiooB,  ibid.     An  extensive  review  of  the 


lODo'rjiYui.w  203 

lodothyrin  or  TnTROioniN.  This  body,  \vliicli  was  discovered  by  Bacmann  and 
•which  occurs  in  the  thymus  and  also,  according  to  iScuNrrzi.Kii  and  EwALU.'in  the 
hypophysis  cerebri,  is  a  substance  containing  iodine,  liaving  a  somewhat  dilierent  com- 
position depending  upon  its  origin.  Koos' foiuid  for  tlie  lodothyrin  from  the  multou 
thyroid  ghmds  and  from  human  tiiyroid  ghmds  from  liilTerenl  regions  tlie  following:  4.31 
and  1  A\-:.rm  I;  8.91  and  10.41-10.03^  M  ;  1.40r»  S;  58.24  and  G1.41-57.04;S  C.  lodothyrin 
is  not  a  ,)roteid  body.  The  views  are  somewhat  contradictory  in  regard  to  the  manner  in 
which  it  exists  in  the  gland  (Baumann,  Bum,  Ta.muach^),  but  one  tniiig  is  sure,  and  that 
is  that  it  is  split  oil  from  complex;  protein  substance  in  the  gland  by  the  prolonged  boil- 
ing with  lOjo  sulphuric  acid. 

lodothyrin  is  an  amorphous,  brown  substance  which  swells  upon  heating  and  develops 
an  odor  recalling  the  pyridin  bases.  It  is  nearly  in.soluble  in  water  and  cold  alcohol.  It 
dissolves  with  difficulty  in  boiling  alcohol.  AlUalies  dissolve  it  readily,  and  it  is  pre- 
cipitated from  this  solution  by  the  addition  of  acid.  It  dissolves  with  a  dark  brown  color 
in  concentrated  mineral  acids  and  glacial  acetic  acid.  The  acetic  acid  solution  may  be 
strongly  diluted  with  water  without  precipitation,  and  this  solution  canbe  precipitated  by 
potassium  ferrocyanide,  picric  acid,  or  phospho-tungstic  acid.  lodothyrin  does  not  give 
either  the  Biuret  test  or  Millon's  reaction. 

lodothyrin  is  prepared  by  boiling  the  finely  divided  gland  with  dilute  sulphuric  acid 
(1  :  10)  for  at  least  30  hours.  Pepsin  digestion  may  also  be  rcorted  to.  The  insoluble 
residue,  which  contains  the  iodotnyrin,  is  e.xtracted  in  either  case  with  boiling  alcohol 
(90;e).  On  the  evaporation  of  the  alcoholic  extract  the  residue  is  dissolved  in  water  with 
the  aid  of  a. little  alkali,  and  the  lodothyrin  precipitated  by  the  addition  of  acid. 

According  to  Baumann  and  Eoos  the  iodothyrin  is  the  only  active  sub- 
stance of  the  thyroid  gland,  and  it  gives  all  the  characteristic  actions  of  the 
gland  substance.  According  to  them  it  has  the  t]iera2:)eutlc  action  of  the 
thyroid  preparations  in  goitre,  it  produces  the  characteristic  poisonous 
symptoms  in  large  doses,  it  is  active  in  myxcedema,  and  it  acts  like  the 
gland  substance  on  metabolism  and  proteid  destruction.  This  is  denied  by 
several  other  investigators,^  and  it  is  rather  generally  admitted  that  none  of 
the  thyroid  constituents  thus  far  isolated  has  all  the  typical  actions. 
These  hitter  are  the  united  result  of  several  bodies.  It  is  impossible  to 
enter  here  into  this  and  other  disputed  questions,  such  as  the  importance  of 
iodothyrin,  on  the  origin  and  binding  of  the  iodine  in  the  gland,  the  extent 
and  value  of  the  iodine  metabolism,  the  various  anti-poisonous  theories, 
etc.,  etc. 

Oswald  '  has  isolated  two  protein  substances  from  the  thyroid  gland,  one 
of  which  has  the  characteristics  of  a  globulin,  being  called  thyreoghhtilin, 
and  has  the  following  composition:  C  52.21;    II   6.83;    N  16.59;  I  1.G6; 

literature  on  the  action  of  iodothyrin  and  the  thyroid  preparations  can  be  found  in  Roos, 
Zeitschr.  f.  physiol.  Chem.,  Bd.  22,  S.  18.  In  regard  to  their  action  in  proteid  destruc- 
tion and  metabolism  see  F.  Voit,  Zeitschr.  f.  Biologic,  Bd.  oh  ;  Schondorff,  Pfliiger's 
.  Arch.,  Bd.  67,  and  Anderson  and  Bergman,  Skand,  Arch.  f.  Physiol.,  Bd.  8.  A  sum- 
mary of  the  thyroid  literature  for  the  last  years  is  found  in  Maly's  Jahresber.,  Bdd.  24 
and  25. 

'  Wien.  klin.  Wochenschr.,  1896. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  25. 

*  Baumann,  1.  c. ;  Blum,  Miinch.  mcd.  Wochenschr.,  1898;  Tambach,  Zeitschr.  f. 
Biologic,  Bd.  36, 

*  See  Wormser,  Pfliiger's  Arch.,  Bd.  67  (index  to  literature),  and  foot-note,  p.  202. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  27. 


204  CHYLE,  LYMPH,  TRANSUDATIONS  AND   EXUDATIONS. 

S  1.8G/<.  This  globnlin  is,  according  to  Oswald,  the  iodized  sabsfcance  of 
the  thyroid  gland,  and  it  has  the  specific  action  of  iodothyrin  on  the  proteid 
metabolism.  A  body  containing  5.27^  iodine  was  obtained  from  this, 
globulin  by  pepsin  digestion.  On  boiling  with  10^  sulphuric  acid  Oswald 
obtained  a  substance  which  showed  properties  similar  to  iodothyrin  and 
contained  14.39^  iodine  (average).  This  substance  is  purer  iodothyrin  than 
that  prepared  by  Baumann.  The  second,  less  abundant  protein  substance 
occurring  in  the  thyroid  gland  is  a  nucleoprofceid,  free  from  iodine  (with 
0.16^  P),  which  has  no  action  on  proteid  metabolism.  The  colloid  of  the 
thyroid  gland  of  the  anatomists  is  a  mixture  of  thyreoglobulin  and  nucleo- 
proteid. 

In  "struma  cystica"  Hoppe-Setlee  found  hardly  any  proteid  in 
the  smaller  glandular  vessels,  but  an  excess  of  mucin,  while  in  the  larger 
he  found  a  great  deal  of  proteid,  70-80  p.  m.^  Cholesterin  is  regularly 
found  in  such  cysts,  sometimes  in  such  large  quantities  that  the  entire 
contents  form  a  thick  mass  of  cholesterin  plates.  Crystals  of  calcium 
oxalate  also  occur  frequently.  The  contents  of  the  struma  cysts  are  some- 
times of  a  brown  color  due  to  decomposed  coloring  matter,  methcemoglohin 
(and  haematin  ?).  Bile-coloring  matters  have  also  been  found  in  such  cysts. 
(In  regard  to  the  paralbumins  and  colloids  which  have  been  found  in  struma 
cysts  and  colloid  degeneration,  see  Chapter  XIII.) 

The  Suprarenal  Capsule.  Besides  proteids,  substances  of  the  connective 
tissue,  and  salts,  we  find  in  the  suprarenal  caps  tile  inosit,  pmmitin, 
relatively  considerable  lecithin,  neurin,  and  glycero-phosphoric  acid.  The 
leucin  found  by  certain  experimenters  is  perhaps  only  a  decomposition 
product.  The  statements  as  to  the  occurrence  of  benzoic  acid,  hippuric 
acid,  and  bile  acids  could  not  be  substantiated  by  Stadelmanx.^  In  the 
medulla  Vulpian  and  Arxold  have  found  a  chromogen,  which  is  con- 
verted into  a  red  pigment  by  the  action  of  air,  light,  alkalies,  iodine,  and 
other  bodies.  This  chromogen,  which  in  certain  regards  acts  like  pyro- 
catechin,  has  a  strong  reducing  action.  Because  of  the  amount  of 
chromogen  contained  in  the  suprarenal  body,  a  connection  is  claimed 
between  the  abnormal  deposition  of  pigment  in  the  skin,  which  is  character- 
istic of  Addisox's  disease,  and  tlie  abnormal  changes  which  often  occur  in 
the  suprarenal  body. 

Nothing  positive  is  known  as  to  the  functions  of  the  suprarenal  capsule, 
with  the  exception  of  the  action  of  the  so-called  sphygmogenin.  It  has 
been  shown  by  Oliver  and  Sciiafer,  Cybulski  and  Szymonowicz  '  that 

'Physiol.  Chem.,  S.  731. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18,  which  coutaius  the  uecessaiy  litenituie. 

'  Oliver  and  Schafer,  Proceed,  of  Physiol.  Soc.  Loudon,  189.'!».  Further  references 
in  the  function  of  the  suprarenal  capsule  can  be  found  in  Szymonowicz,  Pflliger's  Arch., 
Bd.  64. 


SUPRARENAL   CAPSULE.  206 

a  watery  extract  of  the  suprarenal  capsule  causes  an  increased  blood- 
pressure.  The  investigations  of  Mooke,  S.  Fkankel,  v.  Fuktii,'  and 
others  show  that  the  substance  hereby  active  stands  in  a  certain  relationsliip 
to  the  ubove-nietitioned  chromogen.  This  substance,  which  Frankbl  calls 
sphygmof)e)ii)i,  is  readily  soluble  in  water  and  also  in  alcohol.  The  supposi- 
tion first  suggested  by  Moore  and  then  made  probable  by  the  researches  of 
Abel  and  Ckawford,  that  this  body  raising  the  increased  blood-pressure 
is  a  p3'ridiu  derivative,  has  received  important  support  from  the  recent  inves- 
tigations of  V.  FcRTH.*  According  to  him  this  questionable  substance  is 
probably  a  dioxypyridin. 

'  Moore,  Proceed,  of  Physiol.  Soc.  London,  1895  (with  Oliver  and  Schafer),  and 
Journal  of  Physiol.,  Vol.  21;  S.  Frankel,  Wieu.  med.  Blatter,  1896;  v.  Furth,  Zeit- 
schr.  f.  physiol.  Chem.,  Bd.  24.  See  also  Giirber,  Sitzungsber.  der  phys.  med.  Gesellsch. 
zu  Wurzburg.  1897,  No.  4. 

"  Moore,  Jouru.  of  Physiol.,  Vol.  21  ;  Abel  and  Crawford,  Johns  Hopkins  Hospital 
Bulletiu,  1897;  v.  Furth,  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 


CHAPTEE  Aail. 
THE   LIVER. 

The  liver,  which  is  the  largest  organ  of  the  body,  stands  in  close 
relationship  to  the  blood-forming  organs.  The  importance  of  this  organ 
for  the  physiological  composition  of  the  blood  is  evident  from  the  fact  that 
the  blood  coming  from  the  digestive  tract,  laden  with  absorbed  bodies,  must 
circalate  through  the  liver  before  it  is  driven  by  the  heart  through  the 
different  organs  and  tissues.  It  has  been  proved,  at  least  for  the  carbo- 
hydrates, that  an  assimilation  of  the  absorbed  nutritive  bodies  which  are 
brought  to  the  liver  by  the  blood  of  the  portal  vein  takes  place  in  this  organ, 
and  there  is  no  doubt  that  synthetical  processes  appear.  The  occurrence 
of  synthetical  processes  in  the  liver  has  been  positively  proved  by  special 
observations.  It  is  possible  that  in  the  liver  certain  ammonia  combinations 
are  converted  into  urea  or  uric  acid  (in  birds),  while  certain  products  of 
putrefaction  in  the  intestine,  such  as  phenol,  may  be  converted  by  synthesis 
into  ethereal  sulphuric  acids  by  the  liver  (Pfluger  and  Kociis').  The 
liver  has  also  the  property  of  removing  and  retaining  heterogeneous  bodies 
from  the  blood,  and  this  is  not  only  true  of  metallic  salts,  which  are  often 
retained  by  this  organ,  but  also,  as  Schiff,  Lautenbergeh,  Jacques, 
Heger,  and  especially  Eoger  have  shown,  the  alkaloids  are  retained  and 
are  probably  also  partially  decomposed  in  the  liver.  Toxins  are  also 
retained  by  the  liver,  and  hence  this  organ  has  a  protective  action  against 
poisons.'  The  researches  of  Bouchard,  Eoger,  and  Mairet  and  Vries' 
has  shown  that  the  liver  may  itself  have  a  poisonous  action. 

Even  though  the  liver  is  of  assimilatory  importance  and  purifies  the 
blood  coming  from  the  digestive  tract,  it  is  at  the  same  time  a  secretory 
organ  which  eliminates  a  specific  secretion,  the  bile,  in  the  production  of 
which  the  red  blood-corpuscles  are  destroyed,  or  at  least  one  of  their  con- 
stituents, the  haemoglobin.     It  is  generally  admitted  that  the  liver  acts 

1  Pflligcr's  Arch.,  Bd.  20  and  Bd.  23,  S.  169. 

"^  Tloirer,  Action  dii  foie  sur  les  poisons  (Paris,  1887),  wbicli  also  contains  the  older 
literature  ;  Buiichnrd,  Lef;ons  sur  les  autointoxications  dans  les  Maladies  (Paris,  1887); 
and  E.  Kotliur  in  Arch,  des  sciences  biologique  de  St.  Petersbourg,  Tome  2,  No.  4,  p. 
587. 

*  See  Mairet  and  Vries,  Arch,  de  Physiol.  (5),  Tome  9. 

206 


PliOTEWS   OF  THE  LI  V Eli.  207 

contrariwise  during  fmtal  life,  at  tliat  time  forming  tlie  red  blood-cor- 
puscles. 

There  is  no  doubt  that  tlie  chemical  operations  going  on  in  tiiis  organ 
are  manifold  and  must  be  of  the  greatest  importance  for  the  organism;  but 
unfortunately  we  know  very  little  about  the  kind  and  extent  of  these 
processes.  Among  them  are  two  principal  ones  which  will  be  fully  treated 
in  this  cha2)ter,  after  we  have  first  described  the  constituents  and  tlie 
chemical  composition  of  the  liver.  One  of  these  processes  seems  to  be  of 
an  assimilatory  nature  and  refers  to  the  formation  of  glycogen,  while  the 
other  refers  to  the  production  and  secretion  of  the  bile. 

The  reaction  of  the  liver-cell  is  alkaline  during  life,  but  becomes  acid 
after  death.  This  change  is  probably  due  to  the  formation  of  lactic  acid, 
causing  a  coagulation  of  the  proteids  of  the  protoplasm  of  the  cell.  A 
positive  difference  between  the  albuminous  bodies  of  the  dead  and  the, 
living,  non-coagulated  protoplasm  has  not  been  observed. 

Hhe  proteids  of  the  liver  were  first  carefully  investigated  by  Plosz.  He 
found  in  the  watery  extract  of  the  liver  an  album i/iotis  substance  which 
coagulates  at  -f-  45°  C,  also  a  globulin  which  coagulates  at  -f-  75°  C,  a 
iinch'oaUmuiin  which  coagulates  at  +  "^0°  C,  and  lastly  a  proteid  body 
which  is  nearly  related  to  coagulated  albumins  and  which  is  insoluble  in 
dilute  acids  or  alkalies  at  the  ordinary  temperature,  but  dissolves  on  the 
application  of  heat,  being  converted  into  an  albuminate.  IIallibuhtox  ' 
has  found  two  globulins  in  the  liver-cells,  one  of  which  coagulates  at 
G8-70"  C,  and  the  other  at  45-50°  C.  lie  also  found,  besides  traces  of 
albumin,  a  nucleoproteid  which  contained  1.45,''^  phosphorus  and  a  coagula- 
tion-point of  00°  C.  Among  the  nucleo2)roteids  of  the  liver-cells  we  find 
also  glycoproteids,  wdiicli  yield  pentose  as  cleavage  products.''  Besides 
these  proteids,  the  liver-cells  contain  a  large  quantity  of  a  difficultly  soluble 
protein  substance  (see  Plosz).  It  also  contains,  as  first  shown  by  St.  Zale- 
SKi  and  then  substantiated  by  several  other  investigators,  ferruginous 
IH'oteids  of  different  kinds.  A  part  of  these  ferruginous  proteids  are,  as 
generally  admitted,  iron  albuminates,  in  which  the  iron  can  be  directly 
detected,  as  after  extraction  wMth  alcohol  containing  hydrochloric  acid. 
They  are  also  in  part  undoubtedly  nucleoproteids,  in  which  the  iron  cannot 
be  directly  detected  (Wolteiukg,  Spitzer).  A  proteid  rich  in  iron, 
obtained  by  Sciimiedeberg  '  by  boiling  the  liver  in  water  and  precipitating 
the  filtrate  with  tartaric  acid,  is  called /crra^m. 

'  Plosz,  Ptiiiger's  Arch.,  Bd.  7;  HuUiburlon,  Journ.  of  Physiol.,  Vo;.  13.  Suppk- 
meut,  1892. 

'  See  Salkowski,  Berl.  klin.  Wochenschr..  1895  ;  Hamniarsten,  Zeitschr.  f.  pliysiol. 
Chem.,  B(l.  9  ;  and  Blunieuthal,  Zeitschr.  f.  klin.  Med.,  Bd.  34. 

*St.  Zaleski,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  10,  S.  486;  Woltering.  ibid.,  Bd.  21; 
Spitzer,  PflUger's  Arch.,  Bd.  67  ;  Schmiedeberg,  Arch.  f.  exp.  Path.  u.  Phariu.,  Bd.  33. 
See  also  Vay,  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 


208  THE  LIVER. 

The  yellow  or  brown  pigment  of  the  liver  has  been  little  studied.  Dastre  and 
FiiOKESCO'  differentiate  in  vertebrates  between  a  ferruginous  pigment  soluble  in  water 
and  a  pigment  soluble  in  chloroform  and  insoluble  in  water.  They  have  not  isolated  these 
pigments  in  a  pure  condition. 

The  fat  of  the  liver  occars  partly  as  very  small  globules  and  partly 
(especially  in  nursing  children  and  sucking  animals,  as  also  after  food  rich 
in  fat)  as  rather  large  fat-drops.  The  occurrence  of  a  fat  infiltration,  i.e., 
a  fat  transportation  in  the  liver,  may  not  onl}'  be  produced  by  an  excess  of 
fat  in  the  food  (Noel-Patok),  but  also  by  emigration  from  other  parts  of 
the  body  under  abnormal  conditions,  such  as  poisoning  with  phosphorus 
(Leo)  and  phlorhizin  (Rosenfeld ').  Eosenfeld  ^  has  given  a  new  series 
of  investigations  on  fatty  liver  in  phlorhizin-diabetes.  Dogs  whose  fat 
deposit  was  changed  by  prolonged  feeding  with  a  foreign  fat  (mutton-fat), 
and  hence  consisted  of  this  foreign  fat  alone,  were  poisoned  with  phlorhizin. 
It  was  strikingly  shown  that  the  fat  accumulated  in  the  liver  after  the 
poisoning  was  fat  transported  from  the  fat  deposit. 

If  the  amount  of  fat  in  the  liver  is  increased  by  an  infiltration,  the 
water  decreases  correspondingly,  while  the  quantity  of  the  other  solids 
remains^  little  changed.  In  fatty  degeneration  this  is  different.  In  this 
process  the  fat  is  formed  from  the  protoplasm  of  the  cell,  and  the  quantity 
of  the  other  solids  is  therefore  diminished,  while  the  amount  of  water  is  only 
slightly  changed.  To  illustrate  this  we  give  below  the  results  from  a 
normal  liver,  and  also  the  results  obtained  by  Peels  *  in  fatty  degeneration 
and  fatty  infiltration.     The  results  are  in  1000  parts. 

Water.  Fat.  Remaining  Solids. 

Normal  liver 770  30-35               207-195 

Fatty  degeneration 816  87                       97 

Fatty  infiltration 616-621  195-240              184-145 

The  composition  of  the  liver-fat  not  only  seems  to  be  different  in  differ- 
ent animals,  but  is  variable  under  different  conditions.  Thus  ]S"oi;l-Pato]^ 
found  that  the  liver-fat  in  man  and  several  animals  was  poorer  in  oleic  acid 
and  had  a  correspondingly  higher  melting-point  than  the  fat  from  the 
subcutaneous  connective  tissue,  while  Rosexfeld  ^  has  observed  the  reverse 
condition  on  feeding  dogs  with  mutton-fat.  Thiemicii'  has  habitiially 
found  in  children  a  higher  iodine  equivalent  for  the  fatty  acids  from  the 
fat  of  the  liver,  as  compared  with  the  fatty  acids  from  the  subcutaneous 
fatty  tissues,  which  shows  that  the  liver-fat  is  richer  in  oleic  acid.  From 
his  investigations,  as  well  as  from  a  comparison  of  the  food-fat  and  the  fat 

'  Arch,  do  Physiol.  (5),  Tome  10. 

*Noel-Paton,  Journ.  of  Pliysiol.,  Vol.  19;  Leo,  Zeitschr.  f.  Physiol.  Chem.,  Bd.  9; 
Rosenfeld,  see  Maly's  Jahresber. ,  Bd.  25,  S.  44. 
»  Zeitsclir.  f.  klin.  Med.,  36. 

*  Cculraibl.  f.  d.  mod.  Wisseusch.,  Bd.  11,  S.  101. 

^  Cited  from  Lummert,  Ptliiger's  Arch.,  Bd.  71.  ,  .  ■ 

•  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 


JEGORIN.  209 

from  Llie  subcutaneons  connective  tissues  with  tlie  fat  from  fatty  livers  of 
diseased  infants,  he  has  also  concluded  that  in  the  latter  case  a  deposit  of 
fat  from  the  sobcntaneous  tissues  takes  place,  and  not  fat  from  the  food. 

Lecithin  is  a  normal  constituent  of  the  liver,  and  amounts  to  about  23.5 
p.  m.  according  to  Noel-Paton.'  In  starvation  the  lecithin,  according  to 
Noel-Patox,  forms  the  greatest  part  of  the  ethereal  extract,  while  with 
food  rich  in  fat  it,  on  the  contrary,  forms  the  smallest  part.  Cliolesterin 
only  occurs  in  small  quantities.  The  ethereal  extract  also  contains  a 
protagon-like  body,  jecorin. 

Jecorin  was  first  found  by  Drecusel  in  the  liver  of  n  lioise,  and  also  in  the  liver  of 
a  dolphin,  and  later  by  Baldi  in  the  liver  and  spleen  of  other  animals,  in  the  muscles  and 
blood  of  the  horse,  and  in  the  human  brain.  It  contains  suljihur  and  phosphorus,  but  its 
constitution  is  not  positively  known.  Jecorin  dissolves  in  ether,  but  is  precipitated  from 
this  solution  b}^  alcohol.  It  reduces  copper  oxide,  and  it  solidifies  after  boiling  with 
alkalies  to  a  gelatinous  mass.  M.\nas8E'^  has  detected  glucose  as  osazon  in  the  carbo- 
hydrate complex  of  jecorin.  It  may  lead  to  errors  in  the  investigations  of  organs  or 
tissues,  for  it  can  easily  be  mistaken  for  lecithin  on  account  of  its  solubilities  and  because 
it  contains  phosphorus. 

Among  the  extractive  substances  besides  glycogen^  which  will  be  treated 
of  later,  we  find  rather  large  quantities  of  xanihin  bodies.  Kossel  '  found 
in  1000  parts  of  the  dried  substance  1.97  p.  m.  guanin^  1.34  p.  m. 
hypoxanthin,  and  1.21  p.  m.  xantldn.  Adeyiin  is  also  contained  in  the 
liver.  In  addition  there  have  been  found  ^irea  and  iiric  acid  (especially  in 
birds),  and  indeed  in  larger  quantities  than  in  the  hlood,  paralactic  acid, 
leucin,  and  cystin.  In  pathological  cases  inosit  and  tyrosin  have  been 
detected.  The  occurrence  of  hile-coJoring  mattem  in  the  liver-cell  under 
normal  conditions  is  doubtful;  but  in  retention  of  the  bile  the  cells  may 
absorb  the  coloring  matter  and  become  colored  thereby. 

The  mineral  bodies  of  the  liver  consist  of  phosphoric  acid,  potassium, 
sodium,  alkaline  earths,  and  chlorine.  The  potassium  is  in  excess  of  the 
sodium.  Iron  is  a  regular  constituent  of  the  liver,  but  it  seems  in  very 
variable  amounts.  Bunge  has  found  0.01-0.355  p.  m.  iron  in  the  blood- 
free  liver  of  young  cats  and  dogs.  This  was  calculated  on  the  liver  sub- 
stance freshly  washed  with  a  1^  NaCl  solution.  Calculated  on  10  kilos 
bodily  weight,  the  iron  in  the  livers  amounted  to  3.4-80.1  mgm.  Kecent 
determinations  of  the  quantity  of  iron  in  the  liver  of  the  rabbit,  dog, 
hedgehog,  pig,  and  man  have  been  made  by  Guillemonat  and  Lapicque.* 

'  L.  c.     See  also  Hcfter,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28. 

*  Drechsel,  Ber.  d.  silchs.  Gesellsch.  d.  Wissensch.,  188G,  S.  44,  and  Zeitschr.  f. 
Biologic,  Bd.  33;  Baldi,  Du  Bois-Reymond's  Arch.,  1887,  Suppl.,  S.  100;  IManasse, 
Zeitschr.  f.  physiol.  Chem.,  Bd.  20.  On  account  of  the  recent  investigations  of  Bing, 
Centralbl.  f.  Physiol.,  Bd.  12,  it  is  doubtful  whether  jecorin  is  not  only  a  mixture  of 
sugar  and  lecithin, 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  8. 

*  Bunge,  ibid.,  Bd.  IT,  S.  78;  Guillemonat  and  Lapiccjue,  Compt.  rend,  de  Soc.  biol.. 
Tome  48,  and  Arch,  de  Physiol.  (5),  Tome  8. 


210  THE  LIVER. 

The  variation  was  great  in  human  beings.  In  men  the  quantity  of  iron  in; 
the  blood-free  liver  (blood-pigment  subtracted  in  the  calculation)  was 
regularly  more,  and  in  women  less,  than  0,20  p,  m.  (calculated  on  the  fresh 
moist  organ).     Above  0.5  p.  m.  is  considered  as  pathological. 

The  quantity  of  iron  in  the  liver  can  be  increased  by  iron  remedies,  as 
also  by  inorganic  iron  salts.  The  quantity  of  iron  may  also  be  increased  by 
an  abundant  destruction  of  red  blood-corpuscles  or  by  an  abundant  supply 
of  dissolved  hasmoglobin  in  which  also  a  supply  of  iron  combinations,, 
derived  from  the  blood-pigments,  from  other  organs,  such  as  the  spleen  and 
marrow,  to  the  liver,  seem  to  take  place.'  A  destruction  of  blood-pigments, 
with  a  splitting  off  of  combinations  rich  in  iron,  seems  to  take  place  in  the 
liver  in  the  formation  of  the  bile-pigments.  Even  in  invertebrates,  which 
have  no  haemoglobin,  the  so-called  liver  is  rich  in  iron,  from  which  Dastke 
and  Floresco*  conclude  that  the  quantity  of  iron  in  the  liver  of  inverte- 
brates is  entirely  independent  of  the  decomposition  of  the  blood-pigment, 
and  in  vertebrates  it  is  in  part  so.  According  to  these  authors  the  liver 
has,  on  account  of  the  quantity  of  iron,  a  specially  important  oxidizing 
functioii,  which  they  call  the  "  fonction  martiale  "  of  the  liver. 

The  richness  of  the  liver  of  new-born  animals  in  iron  is  of  special 
interest;  a  condition  which  follows  from  the  analyses  of  St.  Zaleski,  but 
especially  studied  by  Kruger,  Meter,  and  Pernou.  In  oxen  and  cows 
they  found  0.246-0.276  p.  m,  iron  (calculated  on  the  dry  substance),  and 
in  the  cow-foetus  about  ten  times  as  much.  The  liver-cells  of  a  calf  a  week 
old  contain  about  seven  times  as  much  iron  as  the  full-grown  animal;  the 
quantity  sinks  in  the  first  four  weeks  of  life,  when  it  about  reaches  the 
same  amount  as  in  the  grown  animal.  Lapicque  ^  has  also  found  that  in 
rabbits  the  quantity  of  iron  in  the  liver  steadily  diminishes  from  the  eighth 
day  to  three  months  after  birth,  namely,  from  10  to  0.4  p.  m.,  calculated 
on  the  dry  substance.  "  The  foetal  liver-cells  bring  an  abundance  of  iron 
into  the  world  to  be  used  up,  within  a  certain  time,  for  a  purpose  not  well 
known."  A  part  of  the  iron  exists  as  phosphate,  and  the  greater  part  in 
combination  in  the  ferruginous  protein  bodies  (St.  Zaleski). 

Kruger^  has  determined  the  quantity  of  calcium  in  full-grown  oxen 
and  calves,  and  finds  respectively  0.71  p.  m.  and  1.23  p.  m.  of  the  dried 
substance.  In  the  foetus  of  the  cow  it  is  lower  than  in  calves.  During 
pregnancy  the  iron  and  calcium  in  the  foetus  are  antagonistic;  namely,  an 
increase  in  the  quantity  of  calcium  in  the  liver  causes  a  diminution  in  the 

'  See  Lapicque,  Compt.  rend.,  Tome  124,  and  Schurig,  Arch.  f.  exp.  Path,  u, 
Pbarm.,  Bd.  41. 

»  Arch,  de  Physiol.  f5),  Tome  10. 

»  St.  Zaleski,  1.  c.;  Kpijger  and  collaborators,  Zeitschr.  f.  Biologie,  Bd.  27;  Lapicque^ 
Waly's  Jahresber.,  Bd.  20. 

*  Zeitschr.  f.  Biologie,  Bd.  31. 


OL7C00EN.  211 

iron,  and  an  increase  in  the  iron  causes  a  decrease  in  the  calcium.  Copper 
seems  to  be  a  jiliysiological  constituent.  Foreign  metals,  such  as  lead, 
zinc,  and  otliers  (also  iron),  are  easily  taken  up  and  retained  for  a  long  time 
by  the  liver. 

V.  IJiBRA  '  found  in  the  liver  of  a  young  man  who  had  suddenly  died 
702  p.  m.  water  and  238  p.  m.  solids,  consisting  of  'lb  p.  m.  fat,  152  j).  m. 
proteid,  gelatin-forming  and  insoluble  substances,  and  01  p.  m.  extrac- 
tive substances. 

Glycogen  and  its  Formation. 

Glycogen  was  discovered  by  Bernard  and  IIexsex  independentlv  of 
eacli  other.  It  is  a  carbohydrate  closely  related  to  the  starches  or  dextrins,. 
with  the  general  formula  C,H,„0^,  perhaps  6(C,II,,0J  -f  H,0  (KClz  and 
Borntrager).  The  largest  quantities  are  found  in  the  liver  of  full-grown 
animals,  and  snuUler  quantities  in  the  muscles  (Bernard,  Nasse").  It  i? 
found  in  very  small  quantities  in  nearly  all  tissues  of  the  animal  body.  Its 
occurrence  in  lymphoid  cells,  blood,  and  pus  has  been*  mentioned  in  a. 
previous  chapter,  r.nd  it  seems  to  be  a  regular  constituent  of  all  cells  capable 
of  development.  Glycogen  was  first  shown  to  exist  in  embryonic  tissues  hj 
Bernard  and  Kuiixe,  and  it  seems  on  the  whole  to  be  a  constitnent  of 
such  tissues  in  which  a  rapid  cell-formation  and  cell-development  is  taking: 
place.  It  is  also  present  in  rapidly  forming  pathological  swellings  (Hoite- 
Seyler).  Certain  animals,  as  certain  mussels,  are  very  rich  in  glycogen 
(Bizio').  Glycogen  also  occurs  in  the  plant  kingdom,  especially  in  many 
fungi.  t 

The  quantity  of  glycogen  in  the  liver,  as  also  in  the  muscles,  depend? 
essentially  upon  the  food.  In  starvation  it  disappears  nearly  completely- 
after  a  short  time,  but  more  rapidly  in  small  than  in  large  animals^, 
and  it  disappears  earlier  from  the  liver*  than  from  the  muscles.  After 
partaking  of  food,  especially  when  rich  in  carbohydrates,  the  liver  be- 
comes rich  again  in  glycogen,  the  greatest  increment  occurring  14  to  1(> 
hours  after  eating  (KClz').  The  quantity  of  liver-glycogen  may  amount 
to  120-100  p.  m.  after  partaking  of  large  quantities  of  carbohydrates. 
Ordinarily  it  is  considerably  less,  namely,  12-30  to  40  p.  m.     According  to 

'  See  V.  Goiup-Besaiiez,  Lelirbuch,  4.  Aufl.,  S.  711. 

'  CI.  Bernard,  Compt.  rend.,  Tome  44,  p.  578  ;  aud  Hensen,  Vircbow's  Arch.,  Bd- 
11,  S.  395;  Kiilz  and  Borntriiger,  Pliliger's  Arch.,  Bd.  24,  S.  19;  Nasse,  ibid.,  Bd.  2, 
S.  97. 

5  Bernard,  Conqn.  rend..  Tome  48;  Kiilme,  Lebrbucb  d.  pbysiol.  Chem.,  S.  307 1 
Hoppe-Seyler,  Pfliiger's  Arcb.,  Bd.  7,  S.  409  :  Bizio.  Compt.  rend..  Tome  62. 

*  See  AkleliolT,  Zeitscbr.  f.  Biologie,  Bd.  25,  wbicb  contains  a  summary  of  tbe  liter- 
ature,    llergenb.'ibn,  ibid..  Bd.  27. 

^  Pflliger's  Arcb.,  Bd.  24.  Tbis  important  article  contains  numerous  data  in  regard, 
to  tbe  literature  of  glycogen. 


212  THE  LIVER. 

Cremek  '  the  quantity  of  glycogen  in  plants  (yeast-cells)  is,  as  in  animals, 
dependent  upon  the  food.  According  to  him  the  yeast-cells  contain  gly- 
cogen, which  disappears  from  the  cells  in  the  auto-fermentation  of  the  yeast, 
but  reappears  on  the  introduction  of  the  cells  into  a  sugar  solution. 

The  quantity  of  glycogen  of  the  liver  (and  also  the  muscles)  is  also 
dependent  upon  rest  and  activity,  because  during  rest,  as  in  hibernation,  it 
increases,  and  during  work  it  diminishes.  KuLZ  has  shown  that  by  hard 
work  the  quantity  of  glycogen  in  the  liver  (of  dogs)  is  reduced  to  a 
minimum  in  a  few  hours.  The  muscle-glycogeu  does  not  diminish  to  the 
same  extent  as  the  liver-glycogen.  Kulz  ^  was  able  to  completely  consume 
the  liver-  as  well  as  the  muscle-glycogen  of  a  rabbit  in  3-5  hours  by  qual- 
ified strychnin  poisoning.' 

'  Glycogen  forms  an  amorphous,  white,  tasteless,  and  inodorous  powder. 
It  gives  an  opalescent  solution  with  water  which,  when  allowed  to  evaporate 
on  the  water-bath,  forms  a  pellicle  over  the  surface  that  disappears  again  on 
cooling.  The  solution  is  dextrogyrate,  (a)D  =  +  196°.  63  (Huppert'). 
The  specific  rotatory  power  is  given  somewhat  differently  by  various  inves- 
tigators. A  solution  of  glycogen,  especially  on  the  addition  of  NaCl,  is 
colored  wine-red  by  iodine.  It  may  hold  copper  oxyhydrate  in  solution  in 
alkaline  liquids,  but  does  not  reduce  it.  A  solution  of  glycogen  in  water  is 
not  precipitated  by  potassium-mercuric  iodide  and  hydrochloric  acid,. but  is 
precipitated  by  alcohol  (on  the  addition  of  NaCl  when  necessary)  or 
ammoniacal  basic  lead  acetate.  It  gives  a  white  granular  precipitate  of 
benzoyl  glycogen  with  benzoyl  chloride  and  caustic  soda.  Glycogen  is  com- 
jDletely  precipitated  by  saturating  its  solution  at  ordinary  temperatures  with 
magnesium  or  ammoniam  sulphate.  It  is  not  precipitated  by  sodium 
chloride  or  half  saturating  with  ammonium  sulphate  (Nasse,  ISTeumeister, 
Halliburton,  Young").  Glycogen  is  not  decomposed  on  prolonged 
boiling  with  dilute  caustic  potash,  but  it  seems  to  be  changed  slightly 
(YiNTSCiiGAU  and  Dietl").  By  diastatic  enzymes  glycogen  is  converted 
into  maltose  or  dextrose,  depending  upon  the  nature  of  the  enzyme.  It  is 
transformed  into  dextrose  by  dilute  mineral  acids.  According  to  Tebb,^ 
various  dextrins  appear  as  intermediary  steps  in  the  saccharification  of 
glycogen,  depending  on  whether  the  hydrolysis  is  caused  by  mineral  acids 
or  enzymes. 

1  Zeitschr.  f.  Biologic,  Bd.  31. 

'  PHliger's  Ai'cb.,  Bd.  24,  and  "  Beitrilge  zur  Kenntniss  des  Glykogens."  C.  Lud- 
wig's  Festschrift.     Marburg,  1891. 

*  In  regard  to  the  action  of  experimental  bile-stoppage  on  the  quantity  of  glycogen 
in  the  liver,  see  Reusz,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  41. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

'  See  Young,  Journ.  of  Physiol.,  Vol.  22,  where  the  other  investigators  are  cited. 
«  PflUger's  Arcli.,  Bd.  13,  S.  253. 
*>  Journ.  of  Physiol.,  Vol.  22. 


rUEPAHATlON  OF  GLYCOGEN.  213 

The  preparation  of  pnre  glycogen  (simplest  from  the  liver)  is  generally 
performed  by  the  method  suggested  by  KiiOt'KE,  of  which  the  main  points 
are  the  following:  Immediately  after  the  death  of  the  animal  the  liver  is 
thrown  into  boiling  water,  then  linely  divided  and  boiled  several  times  with 
fresh  water.  The  liltered  extract  is  now  sufliciently  concentrated,  allowed 
to  cool,  and  the  proteids  removed  by  alternately  adding  potassium-mercuric 
iodide  and  hydrochloric  acid.  The  glycogen  is  precipitated  from  the 
filtered  liquid  by  the  addition  of  alcohol  until  the  liquid  contains  G(J  vols, 
per  cent.  The  glycogen  is  first  washed  on  the  filter  with  00^  and  then 
with  95c^  alcohol,  then  treated  with  ether  and  dried  over  sulphuric  acid. 
It  is  always  contaminated  with  mineral  substances.  To  be  able  to  extract 
the  glycogen  from  the  liver  or,  especially,  from  muscles  and  other  tissues 
completely,  which  is  essential  in  a  quantitative  estimation,  these  jiarts  must 
first  be  boiled  for  a  few  hours  with  a  dilute  solution  of  caustic  potash,  say 
4  gms.  KOII  to  100  gms.  liver  and  400  c.c,  water. 

The  quantitative  estimation  is  best  performed  according  to  the  described 
method  of  ]5uucke-Kulz.'  It  is  to  be  observed  that  it  is  necessary  to  heat 
the  liver  for  2-3  hours  and  muscle  4-8  hours  with  caustic-potash  solution. 
This  liquid  must  not  be  concentrated  too  far,  and  must  not  contain  more 
than  2f^  caustic  potash.  It  is  neutralized  by  hydrochloric  acid  and  precipi- 
tated by  the  alternate  addition  of  potassium-mercuric  iodide  and  hydro- 
cliloric  acid.  The  precipitate  must  be  removed  from  the  filter  at  least  four 
times,  suspended  in  water  with  the  addition  of  a  few  drops  IICl  and 
potassium-mercuric  iodide,  and  refiltered  so  that  all  the  glycogen  is  obtained 
in  the  filtrates.  These  are  then  precijiitated  with  double  their  volume  of 
alcohol,  filtered  after  12  hours,  the  precipitate  dissolved  in  a  little  warm 
water,  treated  on  cooling  with  IICl  and  potassium-mercuric  iodide,  filtered, 
and  the  filtrate  again  precipitated  with  alcohol.  Filter  and  carefuily  wash 
the  contents  of  the  filter  with  alcohol  and  ether,  dry,  weigh,  and  incinerate 
to  determine  the  quantity  of  ash  present.  It  is  to  be  recommended  to 
always  test  for  nitrogen  in  a  weighed  part  of  the  dried  and  weighed  precipi- 
tate. If  it  contains  nitrogen,  another  weighed  part  is  boiled  Avith  dilute 
acid  and  converted  into  sugar,  wiiicli  is  determined  by  titration. 

It  sometimes  happens  that  the  liquid,  after  complete  precipitation  of  the 
proteids  with  IICl  and  potassium-mercuric  iodide,  is  cloudy  and  does  not 
filter  clear.  In  this  case  add  2-2^  vols.  95^  alcohol  according  to  Pfi.uckr's  ' 
suggestion.  After  the  liquid  becomes  clear  and  the  precipitate  has  settled 
it  can  be  filtered.  The  precipitate  is  dissolved  in  a  2^r  caustic-potash  solu- 
tion and  again  precipitated  by  hydrochloric  acid  and  potassium-mercuric 
iodide.     Then  proceed  as  above  described. 

We  must  refer  the  reader  to  the  original  communications  in  regard  to 
the  modifications  of  the  above  methods  as  suggested  by  Salkowski  and 
Austin  and  Pfluger,  and  also  IIuizinga's  and  Frankel's"  methods. 

Besides  glycogen  Seegen*  finds  in  the  liver  another  carbohydrate  which 

>  See  R.  KUlz,  Zeitschr.  f.  Biologie,  Bd.  22,  S.  161. 

*  Pflilger's  Aicli.,  Bdd.  53  and  55. 

'  A.ustin,  Virchow's  Arch.,  Bd.  150;  Pfltlger  in  Pfluger's  Arch.,  Bd.  71,  S.  320; 
Huiziugi,  ibid.,  Bd.  61  ;  Friinkel,  ibid.,  Bdd.  52  and  55.  See  also  Weidenbaum,  ibid., 
Bdd.  54  and  55. 

*  Centralbl.  f.  Physiol.,  Bd.  12. 


214  THE  LIVER. 

is  soluble  in  water,  has  a  reducing  action,  and  whicli  lie  designates  "  liver- 
dextrin."  On  heating  with  dilute  hydrochloric  acid  in  a  sealed  tube  it  is 
transformed  into  glucose.  On  treating  the  liver,  according  to  the  Brucke- 
KtJLZ  method,  this  body  goes  into  solution  and  is  only  precipitated  to  a 
slight  extent  with  the  glycogen.  Complete  precipitation  only  takes  place 
in  the  presence  of  90^  alcohol  or  above. 

Numerous  investigators  have  endeavored  to  determine  the  origin  of 
glycogen  in  the  animal  body.  It  is  positively  established  by  the  unanimous 
observations  of  many  investigators '  that  the  varieties  of  sugars  and  their 
anhydrides,  dextrins  and  siarclies,  have  the  property  of  increasing  the 
quantity  of  glycogen  in  the  body.  The  action  of  inulin  seems  to  be  some- 
what uncertain.'  The  statements  are  somewhat  disputed  in  regard  to  the 
actipn  of  the  pentoses.  Ceemer  found  that  various  pentoses,  such  as 
rhamnose,  xylose,  and  arabinose,  have  a  positive  influence  on  the  glycogen 
formation  in  rabbits  and  hens,  and  Salkowski  obtained  the  same  result 
on  feeding  rabbits  and  a  hen  on  arabinose.  Frentzel  found,  on  the 
contrary,  no  glycogen  formation  on  feeding  xylose  to  a  rabbit  which  had 
previousU^  been  made  glycogen-free  by  strychnin  poisoning.' 

The  hexoses,  and  the  carbohydrates  derived  therefrom,  do  not  all 
possess  the  abilit}^  of  forming  or  accumulating  glycogen  to  the  same  extent. 
Thus  C.  YoiT*  and  his  pupils  have  shown  that  dextrose  has  a  more  powerful 
action  than  cane-sugar,  while  milk-sugar  acts  disproportionately  less  (in 
rabbits  and  hens)  than  dextrose,  Isevulose,  cane-sugar,  and  maltose.  The 
following  substances  when  introduced  into  the  body  also  increase  the 
quantity  of  glycogen  in  the  liver:  glycerin,  gelatin,  arhutin,  and  also, 
according  to  the  investigations  of  Kulz,  erythrit,  quercit,  dulcit,  mannit, 
inosii,  allyl  and  crotyl  alcohols,  glycuronic  anhydride,  saccharic  acid,  imicic 
acid,  sodium  tartrate,  saccharin,  isosaccharin,  and  urea.  Ammonium 
carbonate,  glycocoll,  and  asparagin  may  also,  according  to  Eohmaxn",  cause 
an  increase  in  the  amount  of  glycogen  in  the  liver,  xiccording  to  Nebel- 
THAU  other  ammonium  salts  and  certain  amides,  also  certain  narcotics, 
hypnotics,  and  anti-pyretics,  produce  an  increase  in  the  glycogen  of  the 
iiver.  This  action  of  the  antipyretics  (especially  antipyrin)  had  been  shown 
by  Lepine  and  Porteret." 

'  la  reference  to  the  literature  on  this  subject  see  E.  Kiilz,  Plliiger's  Arch.,  Bd.  24, 
and  Ludwifr-Festscbrift,  1891;  Wolffberg,  Zeitscbr.  f.  Biologie,  Bd.  12,  and  C.  Voit, 
iUd.,  Bd.  28,  S.  245. 

5  See  iMiura,  Zeitscbr.  f.  Biologie,  Bd.  32. 

2  Cremer,  Zeitscbr.  f.  Biologie,  Bd.  29,  S.  536  ;  Salkowsld,  Centralbl.  f.  d.  med. 
Wissfnscli.,  1893,  No.  11;  Frentzel,  Pfluger's  Arch.,  Bd.  56. 

■»  Zcit.sfbr.  f.  Biologie,  Bd.  28. 

'  RObmaiin,  Pfliiger's  Arch.,  Bd.  39  ;  Nebcltbau,  Zeitscbr.  f.  Biologie,  Bd.  28  ;  Por- 
4eret,  Compt.  rend.,  Tome  106. 


FORMATION  OF  GLYCOGEN.  215 

The  fats,  notwithstanding  the  above-mentioned  action  of  glycerin,  liave 
no  action  on  the  quantity  of  glycogen  in  the  liver,  according  to  the  state- 
ments of  most  investigators.  According  to  Couvreur  '  the  glycogen  is 
increased  at  th'fe  expense  of  the  fat  in  the  silk-worm  larva  as  it  changes  into 
a  chrysalis.  The  views  in  regard  to  the  action  of  proteids  have  been  very 
contradictory  in  the  past.  It  is  nndoubtedly  settled  from  many  observa- 
tions that  the  proteids  also  increase  the  liver-glycogen.  Amongst  these 
observations  we  must  include  certain  feeding  experiments  with  boiled  beef 
(Naunyn)  or  blood-fibrin  (v.  Mering),  and  especially  the  very  careful 
experiments  made  by  E.  Kulz  on  hens  with  pure  proteids,  such  as  casein, 
seralbumin,  and  ovalbumin.  Wolffberg  "  has  also  shown  that  a  more 
abundant  accumulation  of  glycogen  takes  place  after  feeding  with  proteids 
and  carbohydrates  in  proper  proportions  than  with  carbohydrate  food  alpne 
with  only  a  little  proteid. 

If  we  raise  the  question  as  to  the  action  of  the  various  bodies  in  the 
accumulation  of  glycogen  in  the  liver  we  must  call  to  mind  that  a  forma- 
tion of  glycogen  takes  place  in  this  organ,  and  also  a  consumption  of  the 
same.  An  accumulation  of  glycogen  may  be  caused  by  an  increased  forma- 
tion of  glycogen,  but  also  by  a  diminished  consumption,  or  by  both. 

We  do  not  know  how  all  the  above-mentioned  various  bodies  act  in  this 
regard.  Certain  of  them  probably  have  a  retarding  action  on  the  transfor- 
mation of  glycogen  in  the  liver,  while  others  perhaps  are  more  combustible 
and  in  this  way  protect  the  glycogen.  Some  probably  excite  the  liver-cells 
to  a  more  active  glycogen  formation,  while  others  yield  material  from  which 
the  glycogen  is  formed  and  are  glycogen-formers  in  the  true  sense  of  the 
word.  The  knowledge  of  these  last-mentioned  bodies  is  of  the  greatest 
importance  in  the  question  as  to  the  origin  of  glycogen  in  the  animal  body, 
and  the  chief  interest  attaches  itself  to  the  question,  to  what  extent  are  the 
two  chief  groups  of  food,  the  proteids  and  carbohydrates,  glycogen-formers  ? 

The  great  importance  of  the  carbohydrates  in  the  formation  of  glycogen 
has  given  rise  to  the  opinion  that  the  glycogen  in  the  liver  is  produced  from 
other  carbohydrates  (glucose)  by  a  synthesis  in  which  water  separates  with 
the  formation  of  an  anhydride  (Luchsixger  and  others).  This  theory 
{anhydride  theory)  has  found  opponents  because  it  neither  explains  the 
formation  of  glycogen  from  such  bodies  as  proteids,  carbohydrates,  gelatin, 
and  others,  nor  the  circumstance  that  the  glycogen  is  always  the  same 
independent  of  the  properties  of  the  carbohydrate  introduced,  whether  it  is 
dextrogyrate  or  laevogyrate.  It  is  therefore  the  opinion  of  many  investigators 
that  all  glycogen  is  formed  from  proteid,  and  that  this  splits  into  two  parts, 


'  Compt.  rend,  de  Soc.  biol.,  Tome  47. 

'  Killz,  cited  Festschrift,  where  the  other  investigations  may  be  be  found;  Wolffberg, 
Zeitschr.  f.  Biolosie,  Bd.  16. 


216  THE  LIVER. 

one  containing  nitrogen  and  the  other  being  free  from  nitrogen :  the  latter  is 
the  glycogen.  According  to  these  views,  the  carbohydrates  act  only  iii  that 
they  spare  the  proteid  and  the  glycogen  produced  therefrom  {sparing  tlieory 
of  Weiss,  Wolffberg,  and  others'). 

In  opposition  to  this  theory  C.  and  E.  Yoit^  and  their  pupils  have 
shown  that  the  carbohydrates  are  "  true  glycogen-formers. "  After  partak- 
ino-  of  large  quantities  of  carbohydrates  the  amount  of  glycogen  stored  up 
in  the  body  is  sometimes  so  great  that  it  cannot  be  covered  by  the  proteids 
decomposed  during  the  same  time,  and  in  these  cases  we  must  admit  of  a 
glycogen  formation  from  the  carbohydrates.  The  three  ordinary  mono- 
saccharides and  disaccharides  are  true  glycogen-formers.  Lactose  and  cane- 
Bugar  when  injected  subcataneously  reappear  nearly  entirely  in  the  urine 
(Dastre,  Fr.  Yoit),  and  they  mnst  therefore  first  undergo  an  inversion  in 
the  intestinal  canal  before  they  form  glycogen.  Maltose,  which  is  also  split 
in  the  blood,  passes  only  slightly  into  the  urine  (Dastre  and  Bouequelot, 
and  others),  and  it  can  therefore,  like  the  monosaccharides,  be  of  value  in 
the  formation  of  glycogen  even  after  subcutaneous  injection  (Fr.  Voit'). 

There,  is  no  doubt  that  feeding  with  pure  proteids  leads  to  an  accumula- 
tion of  glycogen,  and  at  the  present  time  we  must  admit  that  glycogen  can 
be  formed  from  proteids  as  well  as  from  carbohydrates. 

The  manner  in  which  glycogen  is  formed  from  proteids  is  not  known. 
The  view  held  by  certain  investigators  that  carbohydrates  split  off  directly 
from  the  genuine  proteids  has  this  foundation,  that  certain  investigators, 
especially  Pavy,  have  been  able  to  split  oU  carbohydrate  groups  from 
proteids.  As  it  is  doubtful  whether  such  a  carbohydrate  can  be  derived 
from  actually  pure  proteid  uncontaminated  with  glycoproteids,  and  also  as 
Buch  proteids  as  casein,  from  which  no  carbohydrate  can  be  prepared,  cause 
an  accumulation  of  glycogen,  we  must  for  the  present  explain  the  formation 
of  glycogen  from  proteids  simply  by  the  assumption  that  a  carbohydrate 
group  is  split  off.  Pflugeir's  ■*  theory  is  therefore  often  cited  to  explain 
the  formation  of  glycogen.  According  to  this  theory  the  glycogen  is  formed 
by  a  complex  cleavage  of  the  proteid  accompanied  by  a  synthesis. 

Like  the  carbohydrates  in  general,  glycogen  has  without  any  doubt  a 
great  importance  in  the  formation  of  heat  and  development  of  energy  in 
the  animal  body.  The  possibility  of  the  formation  of  fat  from  glycogen 
cannot  be  denied.'     Glycogen  is  generally  considered  as  accumulated  reserve 

'  See  Wolffberg,  1.  c,  in  regard  to  these  two  theories. 

«  E.  Voit,  Zeilschr.  f.  Biologie,  Bd.  25,  S.  543,  and  C,  Voit,  ibid.,  Bd.  28.  See  also 
Kausch  and  Socin,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  81. 

*  Dastre,  Arch,  de  Physiol.  (5),  Tome  3,  1891;  Daslru  and  Bourquelot,  Compt.  reud.^ 
Tome  98;  Fritz  Voit,  Verhandl.  d.  Gesellsch.  f.  Morph.  u.  Physiol,  in  Muucheu,  1896, 
and  D'-ul.sch.  Arch.  f.  klin.  Med.,  Bd.  58. 

*  Pflager's  Arch.,  Bd.  42. 

'-  See  especially  Noel-Puton,  Journ.  of  Physiol.,  Vol.  19. 


FORMATION  OF  GLYCOGEN.  217 

food  in  the  liver  and  formed  in  the  liver-cells.  Where  does  the  glycogen 
existing  in  the  other  organs,  such  as  the  muscles,  originate  '.■'  Js  the 
glycogen  of  the  muscles  formed  on  the  spot,  or  is  it  transmitted  to  the 
muscles  by  the-blood  ?  These  questions  cannot  yet  be  answered  with  posi- 
tiveness,  and  the  investigations  on  this  subject  by  dillerent  experimenters 
have  given  contradictory  results.  The  later  experiments  of  Kulz,'  in  which 
he  studied  the  glycogen  formation  by  passing  blood  containing  cane-sugar 
through  the  muscle,  has  led  to  no  conclusive  results.  Still  the  formation 
of  glycogen  from  sugar  in  the  muscles  is  probable.  There  is  no  doubt  that 
glycogen  is  formed  in  the  muscles  during  embryonic  life. 

If  we  consider  that  the  blood  and  lyni2:)h  contain  a  diastatic  enzyme 
which  transforms  glycogen  into  sugar,  and  also  that  the  glycogen  regu- 
larly occurs  in  the  form-elements  and  is  not  dissolved  in  the  fluids,  it  seems 
probable  that  the  glycogen  is  not  transmitted  by  the  blood  to  the  organs  in 
solution,  but  perhaps  more  likely,  if  the  leucocytes  do  not  act  as  carriers, 
is  formed  on  the  spot  from  the  sugar.''  The  glycogen  formation  seems  to 
be  a  general  function  of  the  cells.  In  adults  the  liver,  which  is  very  rich 
in  cells,  has  the  property,  on  account  of  its  anatomical  position,  of  trans- 
forming large  quantities  of  sugar  into  glycogen. 

Tlie  question  now  arises  whether  there  is  any  foundation  for  the  state- 
ment that  the  liver-glycogen  is  transformed  into  sugar. 

As  first  shown  by  Bernard  and  repeated  by  many  investigators,  the 
glycogen  in  a  dead  liver  is  gradually  changed  into  sugar,  and  this  sugar 
formation  is  caused,  as  Bernard  supposed  and  Arthus  and  Huber,  and 
recently  Pavy,'  proved,  by  a  diastatic  enzyme.  This  post-mortem  sugar 
formation  led  Bernard  to  the  assumption  of  the  formation  of  sugar  from 
glycogen  in  the  liver  during  life.  Bernard  suggested  the  following  argu- 
ments for  this  theory:  The  liver  always  contains  some  sugar  under  physio- 
logical conditions,  and  the  blood  from  the  hejiatic  vein  is  always  somewhat 
richer  in  sugar  than  the  blood  from  the  portal  vein.  The  correctness  of 
either  or  both  of  these  statements  has  been  disputed  by  many  investigators. 
Pavy,  Ivitter,  Scuiff,  Eulenherg,  Lussana,  Abeles,  and  others"  deny 
the  occurrence  of  sugar  in  the  liver  during  life,  and  the  greater  amount 
of  dextrose  in  the  blood  from  the  hepatic  vein  is  likewise  disputed  by  them 
and  certain  other  investigators.* 

•  See  Minkowski  and  Lawes,  Arcli.  f.  exp.  Path.  u.  Pharm.,  Bd.  23;  KUlz,  Zeitscbr. 
f.  Biologie,  Bd.  27. 

'  See  Dastre,  Compt.  reud.  de  Soc.  biol.,  Tome  47,  p.  280,  and  Kaufnianii,  ibid.,  p. 
316. 

^Arthus  and  Ihiber,  Arch,  de  Pliysiol.  (5),  Tome  4,  p.  659;  Pavy,  Journal  of 
Physiol.,  Vol.  22. 

■•  lu  regard  to  the  literature  on  sugar  formation  in  the  liver  see  Bernard,  Le9ous  sur 
le  diabiite.  Paris,  1877; — Seegen,  Die  Zuckerbildung  im  Tierkorper.  Berlin,  1890; — 
M.  Bial,  Pfliiger's  Arch.,  Bd.  55,  S.  434. 


218  THE  LIVER. 

The  doctrine  as  to  the  physiological  formation  of  sugar  in  the  liver  has 
obtained  an  energetic  advocate  in  Seegen".  He  maintains,  after  nnmerons 
experiments,  that  the  liver  regalarly  contains  considerable  amounts  of  sugar. 
He  has  observed  an  increase  of  3^  in  the  quantity  of  dextrose  in  the  liver  of 
a  dog  kept  alive  by  passing  arterial  blood  through  the  organ,  and  lastly  he 
has  also  found  in  a  very  great  number  of  experiments  on  dogs  that  the  blood 
from  the  hepatic  vein  always  contains  more — even  double  as  much — sugar 
than  the  blood  from  the  portal  vein.  Mosse  and  Zu]s^TZ  ^  have  recently 
made  objections  as  to  the  correctness  of  this  last  statement,  and  it  follows 
from  the  various  researches  on  this  question  that  when  disturbing  influ- 
ences are  prevented  the  blood  from  the  hepatic  vein  is  only  very  little  richer 
in  sugar  than  the  blood  from  the  portal  vein.  Bing  ^  has  not  been  able  to 
detect  an  appreciable  difference  in  the  quantity  of  reducing  substance  in 
the  portal  vein  as  compared  to  the  hepatic  vein.  Seegen's  assumption 
of  the  formation  of  sugar  from  proteid  or  fat  in  the  liver  has  been  tested 
by  ZuxTZ  and  Cavazzani.'  In  no  case  could  they  find  a  greater  formation 
of  sugar  than  what  corresponded  to  the  glycogen  consumed. 

Altbfiugh  SEEGEi^"  energetically  espouses  the  doctrine  of  Bernard  as  to 
the  vital  sugar  formation  in  the  liver,  still  it  deviates  essentially  from 
Berxard  in  that  he  claims  the  sugar  is  not  derived  from  the  glycogen. 
According  to  Seegex  the  sugar  is  formed  from  peptones  and  fat.  The 
observations  on  which  be  bases  this  view  seem  hardly  to  be  correct,  accord- 
ing to  the  control  experiments  made  by  many  investigators.  The  state- 
ment of  Lepine  as  to  the  occurrence  of  an  enzyme  in  the  blood  which 
has  the  property  of  transforming  peptone  into  sugar  could  not  be  sub- 
stantiated.'' 

The  formation  of  carbohydrate,  or  glucose  from  fat,  a  process  which 
undoubtedly  occurs  in  the  plant  kingdom,  is  also  admitted  for  the  animal 
body,  namely  by  French  experimenters,  especially  Chauveau  and  Kauf- 
MANX.  At  present  we  have  no  positively  conclusive  proof  for  such  a  view. 
The  recent  investigations  of  J.  Weiss  seem  to  show  a  formation  of  sugar 
from  fat  in  the  liver,  while,  on  the  contrary,  the  observations  of  Montuori 
contradict  such  a  process.^     This  question  is  therefore  disputed. 

The  circumstance  that  the  blood-sugar  rapidly  sinks  to  ^-^  of  its  original 
quantity,  or  even  disappears  when  the  liver  is  cut  out  of  the  circulation, 

'  Seegen,   Die  Zuckerbildung,  etc.,  and  Centralbl.   f.  Physiol.,   Bd.   10,  S.  497  and 
822;  Zuiilz,  ihid.,  S.  o61;  Mosse,  Pfluger'.s  Arch.,  Bd.  63. 

'^  "  UndersOgelser  over  reducorende  Subst;mser  i  Blodet."    Kobenhavn,  1899. 
"  Arch.  f.  Auat.  u.  Physiol.,  physiol.  Abth.,  1898. 

*  See  Bial,  Pflliger's  Arcli.,  Bd.  55;  Lcpine,  Compt.  rend..  Tomes   115  and  116;  also 
A.  Cavazzimi  and  A.  Luzzato,  Maly's  Jahresber. ,  Bd.  24;  Paderi,  ibid. 

*  Kaufmaun,  Arch,  de  Physiol.  (5),  Tome  8,  where  Chauveau  is  also  cited;  "Weiss, 
Zeitschr.  f.  physiol.  Chem.,  Bd.  24;  Montuori,  Maly's  Jahresber.,  Bd.  26. 


SUGAR  FORMATION  IN  THE  LIVER.  219 

speaks  for  a  vital  formation  of  sugar  in  the  liver  (8?:egi:x,  Bock,  and 
lIoi'i'MANN;  Kaui-maxx;  Tangl  and  IIarley).  In  geese  whose  livers 
were  removed  from  the  circulation  Minkowski  found  no  sugar  in  the  blood 
after  a  few  hourS.  On  removing  the  liver  from  the  circulation  by  tying  all 
the  vessels  to  iind  from  the  organ,  the  quantity  of  sugar  in  tlie  blood  on 
drawing  is  not  increased  (Schenck  ').  We  will  also  learn  shortly  of  certain 
poisons  and  operative  changes  which  may  cause  an  abundant  elimination  of 
sugar,  but  only  when  the  liver  contains  glycogen.  If  we  recall  the  fact 
shown  by  Rohmann  and  Btal  that  the  lymph  as  well  as  the  blood  contains 
a  diastatic  enzyme,  then  several  reasons  speak  for  the  view  of  Bernard 
that  the  post-mortem  formation  of  sugar  from  the  glycogen  in  the  liver  is  a 
continuation  of  the  vital  process.  Although  it  is  unanimous  that  the  post- 
mortem sugar  formation  is  produced  by  a  diastatic  enzyme,  still  several 
investigators,  such  as  Dastre  and  Noel-Patox,  and  E.  Cavazzax^i,^  are 
of  the  view  that  sugar  formation  is  not  caused  in  life  by  an  enzyme,  but  by 
a  vital  process  of  the  cell  protoplasm. 

The  relationship  of  the  sugar  eliminated  in  the  urine  tinder  certain  con- 
ditions, such  as  in  diabetes  mellitns,  certain  intoxications,  lesions  of  the 
nervous  system,  etc.,  to  the  glycogen  of  the  liver  is  also  an  important 
question. 

It  does  not  enter  into  the  plan  and  scope  of  this  book  to  discuss  in 
detail  the  various  views  in  regard  to  glycosuria  and  diabetes.  The  appear- 
ance of  dextrose  in  the  urine  is  a  symptom  which  may  have  essentially  differ- 
ent causes,  depending  upon  different  circumstances.  Only  a  few  of  the 
most  important  points  will  be  mentioned. 

The  blood  contains  always  about  an  average  of  1.5  ji.  m.,  while  the 
urine  at  most  contains  only  traces.  When  the  quantity  of  sugar  in  the 
blood  rises  to  3  p.  m.  or  above,  then  sugar  passes  into  the  urine.  The 
kidneys  have  the  property  to  a  certain  extent  of  preventing  the  passage  of 
blood-sugar  into  the  urine;  and  it  follows  from  this  that  an  elimination  of 
sugar  in  the  urine  may  be  caused  partly  by  a  reduction  or  suppression  of 
this  above-mentioned  activity  and  partly  also  by  an  abnormal  increase  of  the 
quantity  of  sugar  in  the  blood. 

The  first  seems,  according  to  v.  Merix^g  and  Mix"kowski,  to  be  the 
case  in  phlorhizin  diabetes,  v.  Merixg  has  found  that  a  strong  glycosuria 
appears  in  man  and  animals  on  the  administration  of  the  glucoside 
phlorhizin.     The  sugar  eliminated  is  not  derived  from  the  glucoside.     It  is 

'  Seegen,  Bock  and  IToffmanii,  .«ec  Seegen,  ].  c,  S.  182-184  ;  Kaufraann,  Arch,  de 
Physiol.  (5),  Tome  8;  Tangl  and  llailey,  Pfluger's  Arch.,  Bd.  61;  Minkowski,  Arch.  f. 
exp.  Pa;h.  u.  Pharm.,  Bd.  21;  Schenck,  PflUger's  Arch..  Bd.  57. 

*  Rohm  an  n  and  Bial,  see  foot-note  3,  page  133:  NoOl-Patcn,  "On  Hepatic  Glyco- 
genesis,"  Phil.  Trans,  of  the  Koy.  Soc.  London,  Vol.  185,  and  Journ.  of  Phys^iol.,  Vol. 
22;  Cuvazzani,  Ceutralbl.  f.  Physiol.,  Bd.  8. 


220  THE  LIVER. 

formed  in  the  animal  body,  and  in  fact,  at  least  on  prolonged  starvation, 
from  the  protein  substances  of  tbe  body.  According  to  Contejean  tiie  sugar 
is  partly  if  not  entirely  derived  from  tlie  fats,  but  according  to  tlie  investiga- 
tions of  LusK  such  an  assumption  is  not  admissible.  When  sugar  is  formed 
from  proteid  2.8-2.86  jjarts  sugar  occur  for  every  1  part  nitrogen  in  the 
tirine  (Minkowski  and  Chauyeau)  ;  still  Coktejeax  found  a  considerably 
greater  quantity  of  sugar  in  phlorhizin  diabetes,  whicli  led  him  to  the  above 
view.  According  to'  LusK  a  relatively  greater  quantity  of  sugar  is  elimi- 
nated the  first  day,  by  a  washing  out  of  the  sugar  present,  but  then  the 
relationship  of  2.8  :  1  occurs  and  the  sugar  formation  seems  actually  to  be 
derived  at  the  expense  of  the  proteids.  The  quantity  of  sugar  in  the  blood 
is  not  increased  but  rather  diminished  in  jDhlorhizin  diabetes  (Minkowski), 
which  tends  to  show  that  an  abnormal  elimination  of  sugar  takes  place 
through  the  kidneys.  This  statement  is  disputed  by  certain  investigators, 
Levexe  and  Payy,  and  the  question  is  si  til  unsettled,  i 

With  the  exception  of  phlorhizin  diabetes,  which  is  dependent,  accord- 
ing to  the  ordinary  views,  upon  a  change  in  the  kidneys,  all  other  forms  of 
glycosuria  or  diabetes,  as  far  as  known  at  present,  depend  on  a  hyperglu- 
ccemid. 

A  hyperglucsemia  may  be  caused  in  various  ways.  It  may  be  caused, 
for  example,  by  the  introduction  of  more  sugar  tlian  the  body  can  destroy. 

The  property  of  the  animal  body  to  assimilate  the  diSerent  varieties  of 
sugar  has  naturally  a  limit.  If  too  much  sugar  is  introduced  into  the  intes- 
tinal tract  at  one  time,  so  that  the  so-called  assimilation  limit  (see  ChajDter 
IX,  on  absorption)  is  overreached,  then  the  excess  of  absorbed  sugar 
passes  into  the  urine.  This  form  of  glycosuria  is  called  alimentary  glyco- 
suria,'^ and  it  is  caused  by  the  passage  of  more  sugar  into  the  blood  than 
the  liver  and  other  organs  can  destroy. 

As  the  liver  cannot  transform  all  the  sugar  into  glycogen  which  comes 
to  it  in  alimentary  glycosuria,  it  is  possible  that  a  glycosuria  may  be  pro- 
duced also  under  pathological  conditions  even  by  a  medium  amount  of 
carbohydrate  (100  grms,  glucose)  which  a  healthy  person  could  overcome. 
This  is  the  case  among  others  in  various  affections  of  the  cerebral  system  and 

'  In  regard  to  the  literature  on  phlorhizin  diabetes  see:  v.  Mering,  Zeitschr.  f.  klin. 
]Med  ,  Bdd.  14  and  16;  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31  ;  Moritz  and 
Prausnifz,  Zeitschr.  f.  Biologic,  Bdd.  27  and  29;  Kiilz  and  Wright,  ibid.,  Bd.  27.  S.  181; 
Cremer  and  Hitter,  ibid.,  Bdd.  28  and  29:  Contejeau,  Compt.  rend,  de  See.  biol.,  Torae 
48  ;  Liisk,  Zeitschr,  f.  Biologie,  Bd.  36  ;  Levene,  Journal  of  Physiol.,  Vol,  17  ;  Pavy, 
ibid.,  Vol.  20. 

*  In  regard  to  alimentary  glycosuria  see  Moritz,  Arch.  f.  klin.  Med.,  Bd.  46,  which 
also  contains  the  older  literature;  B.  Rosenberg,  "  Ueber  das  Vorkoinmen  der  alimen- 
tilren  Glykosoria,"  etc.  (Inaug.-Dissert.  Berlin,  1897);  van  Oordt,  Miiuch.  med.  Wochen- 
Kchr..  1898. 


OLTCOSUIIIA  221 

in  certain  chronic  poisoning.  Seecen  includes  the  ligliter  forms  of  diabetes 
in  this  class  of  glycosuria. 

We  differentiate  between  light  and  severe  forms  of  diabetes.  In  the 
first  the  urine  contains  sugar  only  when  carbohydrates  are  taken  as  food, 
while  in  the  other  case  tlie  urine  contains  sugar  even  with  food  entirely 
free  from  carbohydrates.  According  to  the  view  of  Seegex  and  others,  in 
light  forms  of  diabetes  the  liver  is  incapable  of  transforming  all  the  carbo- 
hydrates introduced  into  glycogen,  or  to  utilize  this  in  a  normal  way,  and 
the  activity  of  the  liver-cells  is  also  reduced  or  changed  in  these  cases. 

A  hyperglncjeniia  which  passes  into  a  glycosuria  may  also  be  brought 
about  by  an  excessive  formation  of  sugar  from  the  glycogen  and  other  bodies 
within  the  animal  body. 

The  so-called  ^j/g-wre,  and  also  probably  those  glycosurias  which  occur 
after  other  lesions  of  the  nervous  system,  belong  to  the  above  grouji  of  glyco- 
surias. The  glycosuria  produced  on  poisoning  with  carbon  monoxide, 
curare,  strychnin,  morphin,  etc.,  also  belongs  to  this  group.  That  the 
glycosuria  produced  in  these  cases  is  due  to  an  increased  transformation  of 
the  glycogen  follows  from  the  fact  that  no  glycosuria  appears,  under  the 
above-mentioned  circumstances,  when  the  liver  has  been  previously  made 
free  from  glycogen  by  starvation  or  other  means.  In  other  cases,  as  in 
carbon-monoxide  poisoning,  the  sugar  is  probably  derived  from  the  proteids, 
because  glycosuria  only  occurs  in  those  cases  where  the  poisoned  animal  has 
a  sufficient  quantity  of  proteid  at  its  disposal  (Strai'b  and  Rosexsteix '), 
Proteid  starvation  with  a  simultaneously  abundant  supj-tly  of  carbohydrates 
causes  this  glycosuria  to  disappear. 

A  hypergluca?mia  with  glycosuria  may  also  be  caused  by  a  decreased 
activity  of  the  animal  body  to  consume  or  destroy  the  sugar.  In  this  case 
the  sugar  must  accumulate  in  the  blood,  and  the  formation  of  severe  cases 
of  diabetes  mellitus  is  now  generally  explained  by  this  jirocess. 

The  inability  of  diabetics  to  destroy  or  consume  the  sugar  does  not  seem 
to  be  connected  with  any  decrease  in  the  oxidation  energy  of  the  cells. 
Apart  from  the  fact  that  the  oxidation  processes  are  not  diminished  generally 
in  diabetics  (Schultzex,  Xencki  and  Sieber'),  it  must  be  remarked 
that  the  two  varieties  of  sugar,  dextrose  and  Ijevnlose,  which  are  oxidized 
with  the  same  readiness,  act  differently  in  diabetics.  According  to  Kulz 
and  other  investigators  Iwvulose  is,  contrary  to  dextrose,  utilized  to  a 
great  extent  in  the  organism,  and  may  even  cause  a  deposit  of  glycogen 

'  See  Cock,  PflQger's  Arch.,  Bd.  5:  Bock  and  Hoffmnnn,  Expt.  Stiidien  flber  Diabetes 
(Berlin,  1874).  CI.  Bernard.  Lemons  sur  le  diabet^  (Paris);  T.  Araki.  Zeitschr.  f.  physiol. 
Chem.,  Bd.  15,  S.  351;  Stnuib,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  38;  Rosenstein,  ibid., 
Bd.  40. 

•  Schultzen,-  Bcrl.  klin.  Wochenschr.,  1872  ;  Nencki  and  Sieber,  Joum.  f.  prakt. 
Chem.  (X.  F  ),  Bd.  26,  S.  35. 


222  TUE  LIVER. 

iu  the  liver  in  animals  with  pancreas-diabetes  (Mixkowski ').  The  com- 
bustion of  proteid  and  fat  takes  place  as  in  healthy  subjects,  and  the  fat  is 
completely  burnt  into  carbon  dioxide  and  water.  In  this  diabetes  the 
ability  of  the  cells  to  utilize  especially  the  dextrose  suffers  diminution,  and 
the  explanation  of  this  has  been  sought  in  the  fact  that  the  glucose  is  not 
previously  split  before  combustion. 

According  to  Biedl"  an  experimental  diabetes  can  be  produced  in  dogs 
by  the  exclusion  of  the  chyle  and  lymph  current  by  ligaturing  the  thoracic 
duct  or  by  leading  the  duct -lymph  to  the  outside. 

There  are  also  certain  investigators  who  consider  that  diabetes  is  due  to 
an  increased  production  of  sugar  in  the  liver — a  view  which  has  received 
some  support  in  the  artificially    produced  pancreas-diabetes   (Chauveau, 

KaUFMAN"N,  CAVAZZAlSri). 

The  investigations  of  Minkowski,  v.  Mering,  Domenicis,  and  later 
investigators^  have  shown  that  a  true  diabetes  of  a  severe  kind  is  caused 
by  the  total  extirpation  of  the  pancreas  of  many  ai-imils,  especially  dogs. 
As  in  man  in  severe  forms  of  diabetes,  so  also  in  dogs  with  pancreas- 
diabetes  an  abundant  elimination  of  sugar  takes  place  even  on  the  complete 
exclusion  of  carbohydrates  in  the  food,  and  the  formation  of  sugar  in  these 
cases  is  derived  from  the  protein  substances.  It  seems  iu  man  with  diabetes 
that  the  ability  of  the  sifgar  destruction  is  never  quite  arrested.  In  dogs 
with  pancreas-diabetes  Minkowski  and  v.  Mering,  as  also  Hedox/  have 
been  able,  in  a  few  cases,  to  detect  that  the  total  quantity  of  sugar  intro- 
duced into  the  food  passed  into  the  urine. 

Artificial  pancreas-diabetes  may  also  in  other  respects  present  exactly 
the  same  picture  as  diabetes  in  man ;  but  we  are  not  united  as  to  the  cause  of 
this  diabetes.  According  to  the  Cavazzaxi  brothers,  as  well  as  Chauveau 
and  Kaufmaxx,'  pancreas-diabetes  is  not  or  not  entirely  caused  by  a 
diminished  consumption  of  the  normal  quantity  of  sugar  formed,  but  to  an 
abnormally  increased  formation  of  sugar.  From  this  it  follows  that  the 
pancreas-gland  has  a  regulating  action  on  the  formation  of  sugar  in  the 

'  Kiilz,  Beitrilge  zur  Path.  u.  Theran.  des  Diabetes  niellitus  (Marburg,  1874),  Bd.  1  : 
"Weintraud  and  Laves,  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  19;  Hajxraft,  ibid.;  Minkowski, 
Arch.  f.  exp.  Patb.  u.  Pliarm.,  Bd.  31. 

»  Centralbl.  f.  Pbysiol.,  Bd.  12. 

^  See  Minkowski,  Untersucbungen  liber  Diabetes  mellitus  uacb  Exstirpatioii  des 
Pankreas  (Leipzig,  1893) ;  v.  Noordeii,  "  Die  Zuckerkraukbeit "  (Berli;i.  189G),  wbicb 
contains  a  very  copious  index  of  the  literature.  In  regard  to  diabetes  see  aNo  CI.  Ber- 
nard, Lcrons  sur  le  diabete  (Paris),  and  Seegen,  Die  Zuckerbildung  Im  ThierkOrper 
(Berlin,  1890). 

*  Hedon,  Arcb.  de  Physiol.  (5),  Tome  5. 

'  Cavazzani,  Centralbl. "f.  Pbysiol.,  Bd.  7;  Chauveau  and  Kaufmann,  Mem.  Soc.  bid., 
1893;  Kaufmann,  Arcb.  de  Pbysiol.  (5),  Tome  7,  and  Conipt.  rend,  de  Soc.  biol..  Tome 
47. 


FANCREAS-DIABErES.  '  223 

liver,  a  retarding  action  which  is  caused  by  an  unknown  product  of  th& 
internal  secretion  of  the  pancreas,  and  which  is  absent  on  the  extirpation  ot 
the  ghmd.  Kaufmann  has  made  many  investigations  in  support  of  this 
view.  Among"other  things,  he  has  also  shown  that  on  the  extirpation  of 
the  pancreas  in  liypergluca^mic  animals  the  quantity  of  blood  is  quickly 
diminished  on  cutting  out  the  liver  or  the  portal  circulation.  Montuori  ' 
has  arrived  at  similar  results,  since  the  large  quantity  of  sugar  in  the  blood 
of  dogs  on  ligaturing  the  pancreas-vessels  was  diminished  on  subsequently 
ligaturing  the  liver-vessels.  Kauscii  has  made  similar  observations  on 
birds  with  extirpated  pancreas  and  subsequent  liver  extirpation,  and 
Marcuse'  has  likewise  shown  that  the  simultaneous  extirpation  of  the  liver 
and  pancreas  of  frogs  caused  no  glycosuria  in  any  case  (among  19),  while  the 
extirpation  of  the  pancreas  alone  in  12  animals  operated  upon  (out  of  19) 
caused  a  diabetes. 

There  remains  no  doubt  that  a  certain  relationshij)  exists  between  the 
liver  and  the  elimination  of  sugar  after  the  extirpation  of  the  pancreas, 
although  the  observations  do  not  lead  to  any  positive  conclusion.  The 
investigations  of  Minkowski,  Hedon,  Lancreaux,  Thiroloix,  and 
others '  make  it  probable  that  special  chemical  products  of  the  internal 
secretion  of  the  pancreas  are  here  active.  According  to  these  investigations 
a  subcutaneonsly  transplanted  piece  of  the  gland  can  completely  perform 
the  functions  of  the  pancreas  as  to  the  sugar  exchange  and  the  sugar  elimi- 
nation, because  on  the  removal  of  the  intra-abdominal  piece  of  gland  the 
animal  in  this  case  does  not  become  diabetic.  But  if  the  subcutaneonsly 
imbedded  piece  of  pancreas  is  then  subsequently  removed,  an  active  elimina- 
tion of  sugar  appears  immediately. 

"We  know  nothing  in  regard  to  this  chemically  active  substance  (or  sub- 
stances). Lepine's  assumption  that  a  glycolytic  enzyme  is  specially  formed 
in  the  pancreas  has  been  shown  not  to  be  sufficiently  founded.* 

The  Bile  and  its  Formation. 

By  the  establishment  of  a  biliary  fistula,  an  operation  which  was  iirst 
performed  by  Schwa xx  in  1844  and  which  has  been  improved  lately  by 
Dastre,'  it  is  possible  to  study  the  secretion  of  the  bile.  This  secretion  is 
continuous,  but  with  varying  intensity.     It  takes  place  under  a  very  low 

'  See  Maly's  Jnbiesber.,  Bd.  26. 

'  Kausch,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  37;  Marcuse,  Du  Bois-Revmond's 
Arch..  1S94,  S.  539. 

*  See  Minkowski,  Arch.  f.  exp.  Patli.  u.  Pharm.,  Bd.  31. 

*  Ibid.;  Hedon,  Diabtte  Pancreatique,  Travaux  de  Physiologic  (Laboratoire  do 
Moutpellier,  1898),  and  foot-note  5,  page  133. 

*  Schwann,  Arch.  f.  Anat.  u.  Physiol.,  1844;  Dastre,  Arch,  de  Physiol.  (5),  Tome  2. 


224  THE  LIVEE. 

pressure;  therefore  an  apparently  unimportant  hindrance  in  the  ontflow  of 
the  bile,  namely,  a  stoppage  of  mucus  in  the  exit  of  the  secretion  of  large 
quantities  of  viscous  bile,  may  cause  stagnation  and  absorption  of  the  bile 
by  means  of  tlie  lymphatic  vessels  (absorption  icterus). 

The  quantity  of  bile  secreted  in  the  24  hours  in  dogs  can  be  exactly 
determined.  The  quantity  secreted  by  different  animals  varies,  and  the 
limits  are  2.9-3G.4  gm.  bile  per  kilo  of  weight  in  the  24  hours.' 

The  statements  as  to  the  extent  of  bile  secretion  in  man  are  few  and  not 
to  be  depended  on.  Eanke  found  (using  a  method  which  is  not  free  from 
criticism)  a  secretion  of  14  gm.  bile  with  0.44  gm.  solids  per  kilo  in  24 
hours.  Noiil-Paton,  MATO-EoBSOisr,  Hammaksten,  and  Pfaff  and 
Balcii  "  have  found  a  variation  between  514  and  950  c.c.  per  24  hours. 
Such  determinations  are  of  doubtful  value,  because  in  most  cases  it  follows 
from  the  composition  of  the  collected  bile  that  we  are  not  dealing  with  a 
secretion  of  normal  liver-bile. 

The  quantity  of  bile  secreted  is,  however,  as  specially  shown  by  Stadel- 
MA]srN,\subject  to  such  great  variation  even  under  physiological  conditions 
that  tla^  study  of  these  circumstances  which  influence  the  secretion  is  very 
difficult  and  uncertain.  The  contradictory  statements  by  different  investi- 
gators may  probably  be  explained  by  this  fact. 

In  starvation  the  secretion  diminishes.  According  to  Lukjanow  and 
Albertoxi,*  under  these  conditions  the  absolute  quantity  of  solids  decreases, 
while  the  relative  quantity  increases.  After  partaking  of  food  the  secretion 
increases  again.  The  statements  are  very  contradictory  in  regard  to  the 
time  necessary  after  partaking  of  food  before  the  secretion  reaches  its  maxi- 
mum. After  a  careful  examination  and  compilation  of  all  the  existing 
statements  Heidenhain  ^  has  come  to  the  conclusion  that  in  dogs  the  curve 
of  rapidity  of  secretion  shows  two  maxima,  the  first  at  the  3d  to  5th  hoar, 
and  the  second  at  the  13th  to  loth  hour,  after  partaking  of  food. 

According  to  the  older  statements,  the  proteids,  of  all  the  various 
foods,  cause  the  greatest  secretion  of  bile,  while  the  carbohydrates  diminish, 
or  at  least  excite  much  less  than  the  jiroteids.  It  is  nevertheless  positive 
that  an  increase  in  the  bile  secretion  takes  place  after  a  continuous  over- 

'  lu  regard  to  the  quantity  of  bile  secreted  in  animals  see  Heidenhein,  Die  Gallenab- 
Bonderung,  in  Hermann's  Handbuch  der  Pliysiol.,  Bd.  5,  and  Stadelmann,  Der  Icterus 
Uud  seine  vorscbiodenen  Formen  (Stuttgart,  1891). 

'  Ranlic,  Die  Blutvertbeilung  luid  der  Tliiitigkeitswecbsel  der  Organe  (Leipzig, 
1871);  NoCl-Paton,  Rep.  Lab.  Koy.  Coll.  Edinburgh,  Vol.  3  ;  Mayo-Robson,  Proc.  Roy. 
■Soc,  Vol.  47;  Hammarsten,  Nova  act.  Reg.  Soc.  Scient,  Upsala  (3),  Bd.  16;  Pfaff  and 
Balch,  Journ.  of  Exp.  Med.,  1897. 

"  Stadelmann,  Der  Icterus,  etc.    Stuttgart,  1891. 

*  Lukjanow,  Zeitschr.  f.  physiol.  Chem.,  Bd.  16;  Albertoni,  Recbcrches  sur  la  secre- 
Hon  biliaire.     Turin,  1893. 

'  Llermann's  Handb..  Bd.  5,  and  Stadelmann.  Der  Icterus,  etc. 


BILK  SECUKTION.  226 

abiuulunt  meat  diet.  The  antliorities  are  by  no  means  agreed  as  to  tlie 
action  of  the  fats.  While  many  older  investigators  liave  not  observed  any 
increase,  bat  rather  the  reverse,  in  the  secretion  of  bile  after  feeding  with  fats, 
the  researciies-of  Barhkka  show  an  increase  in  the  secretion  of  bile  on  the 
introduction  of  fat  i)er  os.  According  to  Ivoskxueiuj  olive-oil  is  a  strong 
cholagogue — a  statement  which,  according  to  other  investigators,  Mandel- 
STAMM,  DoYOX  and  Dukoukt'  is  not  snfiiciently  proved. 

The  question  whether  there  exist  special  medicinal  bodies,  so-called 
cholagogues,  which  have  a  specific  exciting  action  on  the  secretion  of  bile 
has  been  answered  in  very  different  Avays.  Many,  especially  the  older 
investigator?,  have  observed  an  increase  in  the  bile  secretion  after  the  use 
of  certain  therapeutic  agents,  such  as  calomel,  rhubarb,  jalap,  turpentine, 
olive-oil,  etc. ;  while  others,  especially  the  later  investigators,  have  arrived 
at  quite  opposite  resnits.  From  all  appearances  this  contradiction  is  due  to 
the  great  irregularity  of  the  normal  secretion,  which  may  be  readily  mis- 
taken in  tests  with  therapeutic  agents. 

ScniFF's  view,  that  the  bile  absorbed  from  the  intestinal  canal  increases 
the  secretion  of  bile  and  hence  acts  as  a  cholagogue,  seems  to  be  a  positively 
proven  fact  by  the  investigations  of  several  experimenters."  Sodium 
salicylate  is  also  perhaps  a  cholagogue  (Stadelmanx,  Doyox"  and 
Dufourt). 

The  bile  is  a  mixture  of  the  secretion  of  the  liver-cells  and  the  so-called 
mucus  which  is  secreted  by  the  glauds  of  the  biliary  passages  and  by  the 
mucous  membrane  of  the  gall-bladder.  The  secretion  of  the  liver,  which  is 
generally  poorer  in  solids  than  the  bile  from  the  gall-bladder,  is  thin  and 
clear,  while  the  bile  collected  in  the  gall-bladder  is  more  ropy  and  viscous 
on  account  of  the  absorption  of  water  and  the  admixture  of  "  mucus,"  and 
cloudy  because  of  the  admixture  of  cells,  pigments,  and  the  like.  The 
specific  gravity  of  the  bile  from  the  gall-bladder  varies  considerably,  being 
in  man  between  1.010  and  1.040.  Its  reaction  is  alkaline  to  litmus.  The 
color  changes  in  different  animals:  golden  yellow,  yellowish  brown,  olive- 
brown,  brownish  green,  grass-green,  or  bluish  green.  Bile  obtained  from 
an  executed  person  immediately  after  death  is  ordinarily  golden  yellow  or 

'  Barbem,  Bull,  della  scienz.  med.  di  Bologua  (7),  5,  and  Maly'3  Jabresber.,  Bd.  24 ; 
Rosenberg,  Pfliiger's  Arch.,  Bd.  46;  IVrandelstamm.  Ueber  deii  Eiulluss  einiger  Arznei- 
miltel  auf  iSckietioii  mid  Zusaiumeusetzung  der  Galle  (Dissert.  Dorpat,  1890);  Doyon 
aud  Dufourt,  Aich.  de  Physiol.  (5),  Tome  9.  lu  regard  to  the  action  of  various  foods 
on  the  secretion  of  bile  sec  also  Ileideiihein,  1.  c.  ;  Sladelmann,  Der  Icterus  ;  aud  Bar- 
bera,  1.  c. 

"  Schiff,  Pfliiger's  Arch.,  Bd.  3.  See  Stadelmauu,  Der  Icterus,  and  the  dissertations 
of  his  pupils,  especially  Winteler,  "  Experimeutelle  Beitriige  zur  Frage  des  Kreislaufes 
der  Galle  "  (luaug. -Diss.  Dorpat,  1892).  aud  Gartner,  "  Experimentelle  BeitrSge  zur 
Physiol,  uud  Path,  der  Gallensekretiou  "  (Inaug.-Diss.  Jurjew,  1893);  also  Stadelmann, 
"  Ueber  den  Kreislauf  der  Galle,"  Zeitschr.  f.  Biologie,  Bd.  34. 


226  THE  LIVER. 

yellow  witli  a  shade  of  brown.  Still  cases  occur  in  which  fresh  human  bile^ 
from  the  gall-bladder,  has  a  green  color.  The  ordinary  post-mortem  bile 
has  a  variable  color.  The  bile  of  certain  animals  has  a  peculiar  odor ;  as 
example,  ox-bile  has  an  odor  of  musk,  especially  on  warming.  The  taste 
of  bile  is  also  different  in  different  animals.  Human  as  well  as  ox  bile  has 
a  bitter  taste  with  a  sweetish  after-taste.  The  bile  of  the  pig  and  rabbit 
has  an  intense  persistent  bitter  taste.  On  heating  bile  to  boiling  it  does 
not  coagulate.  It  contains  (in  the  ox)  only  traces  of  true  mucin,  and  its 
ropy  properties  depend,  it  seems,  chiefly  on  the  presence  of  a  nucleoalbumin 
similar  to  mucin  (Paijkull).  Hammaestex  '  has,  on  the  contrary,  found 
true  mucin  in  human  bile.  The  specific  constituents  of  the  bile  are  Mle- 
acids  combined  with  alkalies,  hile-pigments,  and,  besides  small  quantities  of 
lecithin,  choIesteri)i,  soaps,  neutral  fats,  urea,  and  mineral  substances, 
chiefly  chlorides,  besides  phosphates  of  calcium,  magnesium,  and  iron. 
Traces  of  copper  also  occur. 

Bile  Salts.  The  thus-far  best  studied  bile-acids  may  be  divided  into  two 
groups,  the  glycocliolic  and  taurocholic  acid  groups.  As  found  by  Ham- 
MAKSTEA,''  a  third  group  of  bile-acids  occur  in  the  shark  and  probably  also 
in  other  animals.  They  are  rich  in  sulphur,  and  like  the  ethereal  sulphuric 
acids  they  split  off  sulphuric  acid  on  boiling  with  hydrochloric  acid.  All 
glycocholic  acids  contain  nitrogen,  but  are  free  from  sulphur  and  can  be 
split  with  the  addition  of  water  into  glycocoll  (amido-acetic  acid)  and  a 
nitrogen-free  acid,  cholalic  acid.  All  taurocholic  acids  contain  nitrogen 
and  sulphur  and  are  split,  with  the  addition  of  water,  into  taurin  (amido- 
ethylsulphonic  acid)  and  cholalic  acid.  The  reason  of  the  existence  of 
different  glycocholic  and  taurocholic  acids  depends  on  the  fact  that  there 
are  several  cholalic  acids. 

The  con  jugateil  bile  acid  found  in  the  shark,  and  called  Scymnol  sulphuric  acid  by 
Hammaksten,  yields  as  cleavage  products  sulphuric  acid  and  a  non-nitrogenous  sub- 
stance, scijmn'il  (CjiIlHrtOe),  wliich  gives  the  characteristic  color  reactions  of  cholalic  acid. 

The  different  bile-acids  occur  in  the  bile  as  alkali  salts,  generally  in 
combination  with  sodium,  bat  in  sea-fishes  as  potassium  salts.  In  the  bile 
of  certain  animals  we  find  almost  solely  glycocholic  acid,  in  others  only 
taurocholic  acid,  and  in  other  animals  a  mixture  of  both  (see  below). 

All  alkali  salts  of  the  biliary  acids  are  soluble  in  water  and  alcohol,  but 
insoluble  in  ether.  Their  solution  in  alcohol  is  therefore  precipitated  by 
ether,  and  this  precipitate,  with  the  proper  care  in  manipulation,  gives,  for 
nearly  all  kinds  of  bile  thus  far  investigated,  rosettes  or  balls  of  fine  needles 
or  4-G-sided  prisms  (Plattner's  crystallized  bile).     Presh  human  bile  also 

1  Paijkull,  Zeilschr.  f.  physiol.  Chem.,  Bd.  12;  Ilammarsten,  1.  c,  Nov;i  Act.  (3), 
Bd.  16. 

»  Huramarsteu,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  24. 


BILE  SALTS.  2^7 

crystallizes  readily.  The  bile-acids  and  their  salts  are  optically  active  and 
dextro-rotatory.  The  former  are  dissolved  by  concentrated  sulphuric  acid 
at  the  ordinary  temperature,  forming  a  reddish-yellow  liquid  which  lias  a 
beautiful  green  fluorescence.  On  carefully  warming  with  concentrated 
6ul])huric  acid  and  a  little  cane-sugar,  the  bile-acids  give  a  beautiful  cherry- 
red  or  reddish-violet  liquid.  Pettenkofek's  reaction  for  bile-acids  is  based 
on  this  behavior. 

Pettenkofek's  ted  for  hUe-acids  is  performed  as  follows:  A  small 
quantity  of  bile  in  substance  is  dissolved  in  a  small  porcelain  dish  in  con- 
centrated sulphuric  acid  and  warmed,  or  some  of  the  liquid  containing  the 
bile-acids  is  mixed  with  concentrated  sulphuric  acid,  taking  special  care  in 
botli  cases  that  the  temperature  does  not  rise  higher  than  00-70°  C.  Then 
a  lO,'^  solution  of  cane-sugar  is  added,  drop  by  drop,  continually  stirring 
with  a  glass  rod.  The  presence  of  bile  is  indicated  by  the  production  of  a 
beautiful  red  liquid,  whose  color  does  not  disajipear  at  the  ordinary  tem- 
perature, but  becomes  more  bluish  violet  in  the  course  of  a  day.  This  red 
liquid  shows  a  spectrum  with  two  absorption-bands,  the  one  at  i^  and  the 
other  between  D  and  E,  near  E. 

This  extremely  delicate  test  fails,  however,  when  the  solution  is  heated 
too  high  or  if  an  improper  quantfty — generally  too  much — of  the  sugar  is 
added.  In  the  last-mentioned  case  the  sugar  easily  carbonizes  and  the 
test  becomes  brown  or  dark  brown.  The  reaction  fails  if  the  sulphuric 
acid  contains  sulphurous  acid  or  the  lower  oxides  of  nitrogen.  ]\ranv  other 
substances,  such  as  proteids,  oleic  acid,  amyl  alcohol,  morphin,  and  others, 
give  a  similar  reaction,  and  therefore  in  doubtful  cases  the  spectroscopic 
examination  of  the  red  solution  must  not  be  forgotten. 

Pettenkofek's  test  for  the  bile-acids  depends  essentially  on  the  fact 
that  furfurol  is  formed  from  the  sugar  by  the  sulphuric  acid,  and  this  body 
can  therefore  be  substituted  for  the  sugar  in  this  test  (]\[YLirs).  Accord- 
ing to  Mylius  and  v.  Udkanszky  '  alp.  m.  solution  of  furfurol  should 
be  used.  Dissolve  the  bile,  which  must  first  be  purified  by  animal  charcoal 
in  alcohol.  To  each  c.c.  of  alcoholic  solution  of  bile  in  a  test-tube  add 
1  drop  of  the  furfurol  solution  and  1  c.c.  cone,  sulphuric  acid,  and  cool 
when  necessary  so  that  the  test  does  not  become  too  warm.  This  reaction, 
■when  performed  as  described,  will  detect  -gV-j^  milligram  cholalic  acid 
(v.  Udkanszky).  Other  modifications  of  Pettenkofek's  test  have  been 
proposed. 

Glycocholic  Acid.  The  constitution  of  that  glycocholic  acid,  occurring 
in  human  and  ox  bile,  which  has  been  most  studied  is  represented  by  the 
formula  C„n„XO,.  Glycocholic  acid  is  absent  or  nearly  so  in  the  bile  of 
carnivora.  On  boiling  with  acids  or  alkalies  this  acid,  which  is  analogous 
to  hippuric  acid,  is  converted  into  cholalic  acid  and  glycocoll. 

'  Mylius,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  11;  v.  Udrauszky,  ibid.,  Bd.  12. 


228  THE  LIVER. 

Glycocholic  acid  crystallizes  in  fine,  colorless  needles  or  prisms.  It  is 
soluble  with  difficulty  in  water  (in  about  300  parts  cold  and  120  parts  boil- 
ing water),  and  is  easily  precipitated  from  its  alkali-salt  solution  by  the 
addition  of  dilute  mineral  acids.  It  is  readily  soluble  in  strong  alcohol,  bat 
with  great  difficulty  in  ether.  The  solutions  have  a  bitter  but  at  the  same 
time  sweetish  taste.  The  salts  of  the  alkalies  and  alkaline  earths  are  soluble 
in  alcohol  and  water.  The  salts  of  the  heavy  metals  are  mostly  insoluble  or 
soluble  with  difficulty,  in  water.  The  solution  of  the  alkali  salts  in  water  is 
precipitated  by  sugar  of  lead,  copper-oxide  and  ferric  salts,  and  silver  nitrate. 

The  preparation  of  pure  glycocholic  acid  may  be  performed  in  several 
ways.  We  may  precipitate  the  bile,  which  has  been  freed  from  mucus  by 
means  of  alcohol  and  the  alcohol  removed  by  evaporation,  by  a  solution  of 
lead  acetate.  The  precipitate  is  then  decomposed  by  a  soda  solution  and 
heat,  evaporated  to  dryness,  and  the  residue  extracted  with  alcohol,  which 
dissolves  the  alkali  glycocholate.  The  alcohol  is  distilled  from  the  filtered 
solution  and  the  residue  dissolved  in  water;  this  solution  is  now  decolorized 
by  animal  charcoal,  and  the  glycocholic  acid  precipitated  from  the  solution 
by  the  addition  of  a  dilute  mineral  acid.  The  acid  may  be  obtained  in 
crystals/ either  from  boiling  water,  on  cooling,  or  from  strong  alcohol  by  the 
addition  of  ether.  The  reader  is  referred  to  more  exhaustive  works  for 
other  methods  of  preparation. 

Hyo-glycocholic  Acid,  CaTHisNOe,  is  the  crystalline  glycocholic  acid  obtained  from  the 
bile  of  ihe  pig.  It  is  very  iusoluble  in  water.  The  alkali  salts,  whose  solutions  have  an 
intensely  bitter  taste,  without  any  sweetish  after-taste,  are  precipitated  by  CaCla,  BaCla, 
and  jMgCls,  and  may  be  salted  out  like  a  soap  by  ]Sra2S04  when  added  in  sufficient 
quantity.  Besides  this  acid  there  occurs  in  the  bile  of  the  pig  still  another  glycocholic 
acid  (JoLix  '■). 

The  glycocholate  in  the  bile  of  the  rodent  is  also  precipitated  by  the  above-mentioned 
sulLs.  but  tannot,  lilci;  the  corresponding  salt  in  human  or  ox  bile,  be  precipitated  on 
snturaling  with  a  neutral  salt  (]S'a2S04).  Guano  bile-acid  possibly  belongs  to  the  glyco- 
cholic-acrd  group,  and  is  foimd  in  Peruvian  guano,  but  has  not  been  thoroughly  studied. 

Taurocholic  Acid.  This  acid,  which  is  found  in  the  bile  of  man,  c.ar- 
nivora,  oxen  and  a  few  other  herbivora,  such  as  sheep  and  goats,  has  the 
constitution  C^H^^NSO,.  On  boiling  with  acids  and  alkalies  it  splits  into 
cholalic  acid  and  taurin. 

Taurocholic  acid  may  be  obtained,  though  only  with  difficulty,  in  fine 
needles  which  deliquesce  in  the  air  (Parke").  It  is  very  soluble  in  water, 
and  can  hold  the  difficultly  soluble  glycocholic  acid  in  solution.  This  is 
the  reason  why  a  mixture  of  glycocholate  with  a  sufficient  quantity  of 
taurocholate,  which  often  occurs  in  ox-bile,  is  not  precipitated  by  a  dilute 
acid.  Taurocholic  acid  is  readily  soluble  in  alcohol,  but  insoluble  in  ether. 
Its  solutions  have  a  bitter-sweet  taste.  Its  salts  are,  as  a  rule,  readily  solu- 
ble in  water,  and  the  solutions  of  the  alkali  salts  are  not  precipitated  by 
copper  sulphate,  silver  nitrate,  or  sugar  of  lead.  Basic  lead  acetate  gives, 
on  the  contrary,  a  precipitate  which  is  soluble  in  boiling  alcohol. 

'  Zcitschr.  f.  physiol.  Chem.,  Bdd.  12  and  13. 
'  Hoppe-Seyler,  Med. -chem.  Untersuch.,  S.  160. 


CHOLALJC  ACID.  229 

Tanrocholic  acid  is  best  prepared  from  decolorized,  crystallized  dog-bile, 
which  contains  only  tanrocholate.  The  solution  of  this  bile  is  precipitated 
by  basic  lead  acetate  and  ammonia,  and  the  washed  precipitate  dissolved  in 
boiling  alcohol-!  The  filtrate  is  now  treated  with  II,,S,  and  this  filtrate  is 
evaporated  at  a  gentle  heat  to  a  small  volume,  and  treated  with  an  excess 
of  water-free  ether.     The  acid  sometimes  partially  crystallizes. 

Cheno-taurocholic  Acid.  This  is  the  most  essential  acid  of  goose-bile  and  has  the 
formula  CaoILuNt^O,.  Tliis  acid,  though  little  studied,  is  amorphous  and  soluble  in 
water  and  alcohol. 

As  repeatedly  mentioned  above,  the  two  bile-acids  split  on  boiling  with 
acids  or  alkalies  into  non- nitrogenous  cholalic  acid  and  glycocoll  or  taurin. 
Therefore  we  will  now  describe  the  products  of  this  cleavage. 

Cholalic  Acid  or  Cholic  Acid.  The  ordinary  cholalic  acid  obtained  as  a 
decomposition  product  of  human  and  ox  bile,  which  occurs  regularly  in  the 
contents  of  the  intestine  and  in  the  urine  in  icterus,  has,  according  to 
Strecker  and  nearly  all  recent  investigators,  the  constitution  C^JI^^O^. 
According  to  Mylius,'  cholalic  acid  is  a  monobasic  alcohol-acid  with  a 
secondary  and  two  primary  alcohol  groups.     Its  formula  may  therefore  be 

I  CUOH 
written  C,,H„  ■<  (CH^On)^.     On  oxidation  \i  f^xsiy'ieldi?,  dehydrocholalic  acid 

(COOH 
(IIammarsten),  and  then  hilianic  acid  (Cleve).  The  formulae  of  these 
acids  (when  we  take  C^,  for  the  cholalic  acid)  are  C^JIj^O^  and  C,^H,,Oj. 
On  stronger  oxidation  it  yields  choJesterinic  acid,  which  has  not  been  care- 
fully studied,  and  finally  phtalic  acid,  as  maintained  by  Senkowski,  but  not 
substantiated  by  BuLnEiM.'  On  oxidizing  cholalic  acid  with  potassium 
permanganate  LASSAR-ConN  '  obtained  first  dehydrocholalic  acid,  isobilianic 
and  hilianic  acids,  and  then  on  further  oxidation  of  the  latter  with  perman- 
ganate he  obtained  a  new  acid,  cilianic  acid,  with  the  formula  O^jr^^O,  or 
C„n„0,„.  On  reduction  (in  putrefaction)  cholalic  acid  may  yield  desoxy- 
cholalic  acid  (Mylius).  On  reduction  with  hydriodic  acid  and  red 
phosphorus  Pregl  obtained  a  product  which  he  considers  as  a  mono-carbonic 

acid  with  the  formula  C,„H,,-<  (CH3),.     Senkowski  has  obtained  an  acid 

(  COOH 
with  the  formula  C,^H^„0, ,  cliohjlic  acid,  on  the  reduction  of  the  anhydride.* 

*  The  important  researches  of  Strecker  on  the  bile-acids  may  be  found  in  Annal.  d. 
Chem.  u.  Pharm.,  Bdd.   65,  67,  and  70  ;    Mylius,  Ber.   d.  deutsch.   chem.  Gesellsch. 
Bd.  19. 

*  Hammarsten,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  14;  Cleve,  Bull.  Soc.  chim.. 
Tome  35;  Senkowski,  3Ionatshefte  f.  Chem.,  Bd.  17;  Biilheim,  Zeitschr.  f.  phyisiol. 
Chem.,  Bd.  25,  in  which  the  literature  on  cholesterinic  acid  may  be  found. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  32. 

*  Mylius.  1.  c;  Pregl,  Pfluger's  Arch.,  Bd.  71;  Senkowski,  Mouatshefte  f,  Chem., 
Bd.  19." 


230  THE  LIVER. 

Cholalic  acid  crystallizes  j)artly  ia  rhombic  plates  or  prisms  with  one 
molecule  of  water  and  partly  in  larger  rhombic  tetrahedra  or  octahedra 
with  1  mol.  of  alcohol  of  crystallization  (Mylius).  These  crystals  become 
quickly  opaque  and  porcelain- white  in  the  air.  They  are  qaite  insoluble  in 
water  (in  4000  parts  cold  and  750  parts  boiling),  rather  soluble  in  alcohol, 
but  soluble  with  difficulty  in  ether.  The  amorphous  cholalic  acid  is  less 
insoluble.  The  solutions  have  a  bitter-sweetish  taste.  The  crystals  lose 
their  alcohol  of  crystallization  only  after  a  lengthy  heating  to  100-120°  C. 
The  acid  free  from  water  and  alcohol  melts  at  -|-  195°  C.  It  forms  a  char- 
acteristic combination  with  iodine  (Mylius).    ■ 

The  alkali  salts  are  readily  solable  in  water,  but  when  treated  with  a 
concentrated  caustic  or  carbonated  alkali  solution  may  be  separated  as  an 
oily  mass  which  becomes  crj^stalline  on  cooling.  The  alkali  salts  are  not 
readily  soluble  in  alcohol,  and  on  the  evaporation  of  the  alcohol  they  may 
crystallize.  The  specific  rotatory  power  of  the  sodium  salt  is  {oi)J)  =  -|- 
31°. -i.'  The  watery  solution  of  the  alkali  salts,  when  not  too  dilute,  is 
precipitated  immediately  or  after  some  time  by  sugar  of  lead  or  by  barium 
chlorid^  The  barium  salt  crystallizes  in  fine,  silky  needles,  and  it  is  rather 
insoluble  in  cold,  but  somewhat  easily  soluble  in  warm  water.  The  barium 
salt,  as  well  as  the  lead  salt  which  is  insoluble  in  water,  is  soluble  in  warm 
alcohol. 

Cholalic  acid  is  best  prepared  from  ox-bile  by  the  following  method  as 
suggested  by  Mylius:^  Boil  the  bile  for  21  hours  with  5  parts  its  weight 
of  a  30^  caustic-soda  solution,  replacing  the  water  lost  by  evaporation. 
Now  saturate  the  liquid  Avith  CO^  and  evaporate  nearly  to  dryness.  The 
residue  is  extracted  Avith  96^  alcohol,  and  this  alcoholic  extract  diluted  with 
water  until  it  contains  at  the  most  20^  alcohol,  and  completely  precipitated 
with  a  BaCl^  solution.  The  precipitate,  which  contains  besides  fatty  acids 
also  the  choleic  acid,  is  filtered  and  the  cholalic  acid  precipitated  from  the 
filtrate  by  hydrochloric  acid.  After  the  cholalic  acid  has  gradually  crystal- 
lized out  it  is  repeatedly  recrystallized  from  alcohol  or  methyl  alcohol. 

Choleic  Acid  is  another  cholalic  acid  with  the  formula  C^JI^^O^ 
(Lassak-Cohn  ')  named  by  Latsciiinoff.  This  acid,  which  occurs  in 
varying  but  always  small  quantities  in  ox-bile,  is  probably  identical  with 
desoxycholalic  acid.  Choleic  acid  first  yields  dcliydroclioleic  acid,  Cj^II,^0^ , 
and  then  cliolanic  acid,  C^/lIj/J, ,  on  oxidation. 

Choleic  acid  may  be  obtained  from  the  above-mentioned  barium  precipi- 
tate by  first  converting  the  barium  salts  into  sodium  salts  by  sodium 
carbonate  and  then  fractionally  precipitating  the  fatty  acids  by  barium 

'  See  Vablen,  Zeitschr.  f.  physiol.  Cbein.,  Bd.  21. 

'  Zeitschr.  f.  pliysiol.  Chcm.,  Bd.  12.     See  also  Vableu  and  Pregl,  1.  c. 

^  Latschinoir,  Ber.  d.  deutsch.  chem.  Gcsellscli.,  Bild.  18  and  20  ;  Lassar-Cobn,  ibid., 
Bd.  26,  and  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  17.  Sec  also  Vablen,  Zeitscbr.  f.  i)liysiol. 
Chem.,  Bd.  23. 


QLTCOCOLL  AND   TAUlilN.  231 

acetate  and  separating  the  clioleic  acid  from  the  filtrate  by  hydrochloric  acid 
and  recrystallizing  several  times  from  glacial  acetic  acid. 

Fellic  Acid,  C^II^.O^ ,  is  a  cholalic  acid,  so  called  by  Sciiotten,  and 
which  he  obtained  from  human  bile,  along  with  the  ordinary  acid.  This 
acid  is  crystalline,  is  insoluble  in  water,  and  yields  barium  and  magnesium 
salts  which  are  very  insoluble.  It  does  not  give  Pettexkoi'ek's  reaction 
easily  and  gives  a  more  reddish-blue  color. 

The  conjugate  acids  of  human  bile  have  not  been  investigated.  To  all 
appearance  human  bile  contains  under  dilferent  circumstances  various 
conjugate  bile-acids.  In  some  cases  the  bile-salts  of  human  bile  are  precipi- 
tated by  BaC'l, ,  and  in  others  not.  According  to  the  latest  statements  of 
Lassak-Coiix  '  three  cholalic  acids  may  be  prepared  from  human  bile, 
namely,  ordinary  cholalic  acid,  choleic  acid,  and  fellic  acid. 

Lithofellic  Acid,  CauHssOi,  is  the  cholulic  ucid  occurring  in  tbe  oriental  bezoar  stones, 
•wliicli  is  insoluble  in  water,  comparatively  easily  soluble  in  alcohol,  but  only  slightly 
soluble  in  ether,' 

The  hyo-glycocholic  and  cheno-taurocholic  acids,  as  well  as  the  glyco- 
cholic  acid,  of  the  bile  of  rodents  yield  corresponding  cholalic  acids. 

On  boiling  with  acids,  on  putrefaction  in  the  intestine,  or  on  heating, 
cholalic  acids  lose  water  and  are  converted  into  an  anhydride,  the  so-called 
ihjsUjsin.  The  dyslysin,  CjJIj.O, ,  corresponding  to  ordinary  cholalic  acid, 
and  which  occurs  in  faeces,  is  amorphous,  insoluble  in  water  and  alkalies. 
Choloidic  acid,  C,  JIj^O^ ,  is  called  the  first  anhydride  or  an  intermediate 
product  in  the  formation  of  dyslysin.  On  boiling  dyslysin  with  caustic 
alkali  it  is  reconverted  into  the  corresponding  cholalic  acid. 

GlycocoU,  CJI^XO, ,  or  amido-acetic  acid,  NII,.CII,.COOH,  also  called 
glycin,  or  sugar  of  gelatin,  has  been  found  in  the  muscles  of  j)ecten 
irradians,  but  it  is  of  special  interest  as  a  decomposition  product  of  certain 
protein  substances — gelatin,  elastin,  fibroin,  and  spougin — as  also  of  hip- 
puric  acid  or  glycocholic  acid  on  splitting  them  by  boiling  with  acids. 

Glycocoll  forms  colorless,  often  large,  hard  rhombic  crystals  or  four- 
sided  prisms.  The  crystals  taste  sweet  and  dissolve  easily  in  cold  (4.3  parts) 
water.  They  are  insoluble  in  alcohol  and  ether;  in  warm  spirits  of  wine 
they  dissolve,  but  with  difficulty.  Glycocoll  combines  with  acids  and  bases. 
Under  the  last-mentioned  combinations  we  must  mention  those  with  copper 
and  silver.  Glycocoll  dissolves  copper  hydroxide]  in  alkaline  liquids,  but 
does  not  reduce  it  at  the  boiling  temperature.  A  boiling-hot  solution  of 
glycocoll  dissolves  freshly  precipitated  cojiper  hydroxide,  forming  a  blue 
liquid  from  which  dark-blue  needles  crystallize  on  cooling,  if  the  liquid  is 

'  Schotteii.  Zeitschr.  f.  physiol.  Cliem.,  Bd.  11  ;  Lassar-Cohn,  Ber.  d.  deutsch.  chem. 
Gesellsch.,  Bd.  27. 

*  See  Jiinger  and  Klages,  Ber.  d.  deutsch.  cheni.  Gesellsch.,  Bd.  28  (older  literature). 


232  •  THE  LIVEB. 

sufficiently  coucentrated.     The  combination  of  glycocoll  with  HCl  is  soluble 
in  water  and  alcohol. 

Glycocoll  is  best  prepared  from  hipjonric  acid  by  boiling  it  10-12  hours 
with  4  parts  of  dilute  sulphuric  acid,  1  :  6.  After  cooling  separate  the 
benzoic  acid,  concentrate  the  filtrate,  remove  the  remainder  of  the  benzoic 
acid  by  shaking  with  ether,  remore  the  sulphuric  acid  by  BaCO^ ,  and 
evaporate  the  filtrate  to  cr^^stallization.  In  the  prejjaration  and  quantitative 
estimation  of  glycocoll  from  gelatin  we  can  proceed  according  to  Ch. 
Fischer  and  GoK^STERMAisrisr  ^  by  converting  it  into  hippuric  acid  by  means 
of  benzoyl  chloride  and  caustic  soda,  and  this  latter  taken  ujd  by  acetic  ether 
after  acidification  with  sulphuric  acid. 

Taurin,  C,H,NS03 ,  or  amido-ethylsulphonic  acid,  NH.C^H^.SO.OII. 
This  body  is  Avell  knoAvn  as  a  cleavage  product  of  taurocholic  acid,  and  may 
occur  in  small  quantities  in  the  contents  of  the  intestine.  It  has  also  been 
found  in  the  lungs  and  kidneys  of  oxen  and  in  the  blood  and  muscles  of 
cold-blooded  animals. 

Taurin  crystallizes  in  colorless,  often  in  large,  shining,  4-G-sided  prisms. 
It  dissolves  in  15-16  j)arts  of  water  at  ordinary  temperatures,  but  rather 
more  easily  in  warm  Avater.  It  is  insoluble  in  absolute  alcohol  and  ether; 
in  cold  spirits  of  wine  it  dissolves  slightly,  but  more  when  Avarm.  Taurin 
yields  acetic  and  sulphurous  acids,  but  no  alkali  sulphides,  on  boiling  with 
strong  caustic  alkali.  The  amount  of  sulphur  can  be  determined  as- 
sulphuric  acid  after  fusing  with  saltpetre  and  soda.  Taurin  combines  with 
metallic  oxides.  The  combination  with  mercuric  oxide  is  white,  insoluble, 
and  is  formed  when  a  solution  of  taurin  is  boiled  with  freshly  precijoitated 
mercuric  oxide  (J.  Lang^).  This  combination  maybe  used  in  detecting 
the  presence  of  taurin.     Taurin  is  not  precipitated  by  metallic  salts. 

The  preparation  of  taurin  from  bile  is  very  simple.  The  bile  is  boiled  a^ 
few  hours  with  hydrochloric  acid.  The  filtrate  from  the  dyslysin  and 
choloidic  acid  is  concentrated  well  on  the  water-bath,  and  filtered  so  as  to 
remove  the  common  salt  and  other  substances  which  have  separated.  Then 
evaporate  to  dryness,  and  treat  the  residue  with  strong  alcohol,  which 
dissolves  the  hydrochlorate  of  glycocoll,  while  the  tanrin  remains.  (The 
alcoholic  solution  of  hydrochlorate  of  glycocoll  may  be  used  in  the  prepara- 
tion of  glycocoll  by  evaporating  the  alcohol  and  dissolving  the  residue  in 
water,  decom^oosing  the  solution  with  lead  hydroxide,  filtering,  and  freeing 
the  solution  from  lead  by  11,8,  and  strongly  concentrating  this  filtrate. 
The  crystals  which  separate  are  dissolved  and  decolorized  by  animal  char- 
coal, and  the  solution  is  evaporated  to  crystallization.)  The  above-obtained 
residue  containing  the  taurin  is  dissolved  in  as  little  water  as  possible, 
filtered  warm,  and  treated  with  an  excess  of  alcohol.  The  crystalline 
precipitate  which  immediately  forms  is  filtered  as  soon  as  possible,  and  the 

'  Cb.  Fischer,  Zeitschr.  f.   physiol.    Chem.,   Bd.    19;  Gonnenaiuun,  Pflligcr's  Arch., 
Bd.  59. 

'  See  Muly'a  Juhiesber.,  Bd.  6. 


niL  K-  riQMKNTS.  233 

tanrin  now  separates,  on  cooling,  in  very  long  needles  or  prisms.  These 
crystals  niiiy  be  puriiied  by  recrystallization  from  a  little  warm  water. 

Though  the  tanrin  shows  no  positive  reactions,  it  is  chiefly  identified  by 
its  crystalline  form,  by  its  solubility  in  water  and  insolubility  in  alcohol,  by 
its  combination  with  mercuric  oxide,  by  its  non-j)recipitability  by  metallic 
salts,  and  above  all  by  its  containing  sulphur. 

Tin;  Dethctiox  of  Bilk-acids  ix  Aximal  Fluids.  To  obtain  the 
bile-acids  pure  so  that  Pettenkofek's  test  can  be  applied  to  them,  the 
proteid  and  fat  must  first  be  removed.  The  proteid  is  removed  by  making 
the  lifpiid  first  neutral  and  then  adding  a  great  excess  of  alcohol,  so  that  the 
mixture  contains  at  least  85  vols,  per  cent  of  water-free  alcohol.  Now  filter, 
extract  the  jn-ecipitated  proteid  with  fresh  alcohol,  unite  all  filtrates,  distil 
the  alcohol,  and  evaporate  to  dryness.  The  residue  is  completely  exhausted 
with  strong  alcohol,  filtered,  and  the  alcohol  entirely  evaporated  from  the 
filtrate.  The  new  residue  is  dissolved  in  water,  and  filtered  if  necessary, 
and  the  solution  precipitated  by  basic  lead  acetate  and  ammonia.  The 
washed  precipitate  is  dissolved  in  boiling  alcohol,  filtered  while  warm,  and 
a  few  drops  of  soda  solution  added.  Then  evaporate  to  dryness,  extract  the 
residue  with  absolute  alcohol,  filter,  and  add  an  excess  of  ether.  The  pre- 
cipitate now  formed  may  be  used  for  Pettenkofek's  test.  It  is  not 
necessary  to  wait  for  a  crystallization;  but  one  must  not  consider  the 
crystals  which  form  in  the  liquid  as  being  positively  crystallized  bile.  It  is 
also  possible  for  needles  of  alkali  acetate  to  be  formed.  For  the  detection 
of  bile-acids  in  urine  see  Chapter  XV. 

Bile-pigments.  The  bile-coloring  matters  known  thus  far  are  relatively 
numerous,  and  in  all  probability  there  are  Still  more.  Most  of  the  known 
bile-pigments  are  not  found  in  the  normal  bile,  but  occur  either  in  post- 
mortem bile  or,  principally,  in  the  bile  concrements.  The  pigments  which 
occur  under  physiological  conditions  are  the  reddish-yellow  bilirubin,  the 
green  biUverdin^  and  sometimes  there  is  also  observed  in  fresh  human  bile 
a  pigment  closely  allied  to  hydrohiUrubin.  The  pigments  found  in  gall- 
stones are  (besides  the  bilirubin  and  biliverdin)  bilifnscin,  biJiprasin^ 
hilihumin,  bilicyajiin  (and  choletJin?).  Besides  these,  others  have  been 
observed  in  human  and  animal  bile.  The  two  above-mentioned  physio- 
logical pigments,  bilirubin  and  biliverdin,  are  those  which  serve  to  give  the 
golden-yellow  or  orange-yellow  or  sometimes  greenish  color  to  the  bile,  or 
when,  as  is  most  frequently  the  case  in  ox-bile,  the  two  pigments  are 
present  in  the  bile  at  the  same  time,  producing  the  different  shades  between 
reddish  brown  and  green. 

Bilirubin.  This  pigment,  according  to  the  common  acceptation,  has  the 
formula  C,,II,,X,0,  (^Ialy)  and  is  designated  by  the  names  ciioi-EPYHuniX", 
BiLiPHiEiN,  bilifulvin,  and  H^MATOiDix.  It  occurs  chiefly  in  the  gall- 
stones as  bilirnbin-calcium.  It  occurs  in  the  liver-bile  of  all  vertebrates,  and 
in  the  bladder-bile  especially  in  man  and  carnivora;  sometimes,  however, 
the  latter  when  fasting  or  in  a  starving  condition  may  have  a  green  bile. 
It  occurs  also  in  the  contents  of  the  small  intestine,  in  blood-serum  of  the 
horse,  in  old  blood  extravasations  (as  hwmatoidin),  and  in  the  nrine  and 


234  THPJ  LIVER. 

the  yellow-colored,  tissue  in  icterus.  Bilirubin  is  derived  in  all  probability 
from  hgematin,  which  it  closely  resembles.  It  is  converted  into  hydro- 
hiliriibin,  C„H,(,X^O,  (Maly)  by  hydrogen  in  a  nascent  state,  which  shows 
great  similarity  to  the  urinary  pigment,  urohiUn,  as  well  as  to  stercohilin 
found  in  the  contents  of  the  intestine  (Masius  and  Vaxlair  ').  On  oxida- 
tion bilirubin  yields  biliverdin  and  other  coloring  matters  (see  below). 

Bilirubin  is  partly  amorphous  and  partly  crystalline.  The  amorphous 
bilirubin  is  a  reddish-yellow  powder  of  nearly  the  same  color  as  amorphous 
antimony  sulphide;  the  crystalline  bilirubin  has  nearly  the  same  color  as 
crystallized  chromic  acid.  The  crystals,  which  can  easily  be  obtained  by 
allowing  a  solution  of  bilirubin  in  chloroform  to  spontaneously  evaporate, 
are  reddish-yellow,  rhombic  plates,  whose  obtuse  angles  are  often  rounded. 

Bilirabiu  is  insoluble  in  water  and  occurs  in  animal  fluids  as  soluble 
bilirubin-calcium.  It  is  slightly  soluble  in  ether,  somewhat  more  soluble  in 
alcohol,  easily  soluble  in  chloroform,  especially  in  the  warmth,  and  less 
soluble  in  benzol,  carbon  disuljohide,  amyl  alcohol,  fatty  oils,  and  glycerin. 
KuSTER*  finds  that  dimethylanilin  is  a  good  solvent  for  bilirubin,  which 
dissolves  0.89  parts  in  100  at  the  ordinary  temperature,  but  2.6  grms.  at  boil- 
ing temperature.  Its  solutions  show  no  absorption-bands,  but  only  a 
continuous  absorption  from  the  red  to  the  violet  end  of  the  spectrum,  and 
they  have,  even  on  diluting  greatly  (1  :  500000),  in  a  layer  1.5  c.cm.  thick 
a  decided  yellow  color.  If  a  dilute  solution  of  bilirubin  in  water  is  treated 
with  an  excess  of  ammonia  and  then  Vvith  a  zinc-chloride  solution,  the 
liquid  is  first  colored  deep  orange  and  then  gradually  olive-brown  and  then 
green.  This  solution  first  gives  a  darkening  of  the  violet  and  blue  part  of 
the  spectrum  and  then  the  bands  of  alkaline  cholecyanin  (see  below),  or  at 
least  the  bands  of  the  pigment  in  the  red  between  C  and  D  close  to  C. 
This  is  a  good  reaction  for  bilirubin.  The  combinations  of  bilirubin  with 
alkalies  are  insoluble  in  chloroform,  and  bilirubin  may  be  separated  from  its 
solution  in  cliloroform  by  shaking  with  dilute  caustic  alkali  (differing  from 
lutein).  Solutions  of  bilirubin-alkali  in  water  are  precij^itated  by  the  solu- 
ble salts  of  the  alkaline  earths  and  also  by  metallic  salts. 

If  an  alkaline  solution  of  bilirubin  be  allowed  to  stand  in  contact  with 
the  air,  it  gradually  absorbs  oxygen  and  green  biliverdin  is  formed.  Bili- 
verdin is  also  formed  from  bilirubin  by  oxidation  under  other  conditions. 
A  green  coloring  matter  similar  in  appearance  is  formed  by  the  action  of 
other  reagents  such  as  CI,  Br,  and  I.  In  these  cases  it  does  not  seem  to  be 
biliverdin,  but  a  substitution  product  of  bilirubin  (Thudichum,  Malt'), 
which  is  obtained. 

'  Maly's  Wien.  Sitzungsber.,  Bd.  57,  and  Annal.  d.  Chem.,  Bd.  163;  Masius  and 
Vanlair,  Centralbl.  f.  d.  med.  Wisseiiscb.,  1871,  S.  369. 

»  Zeitscbr.  f.  physiol.  Cbem.,  Bd.  26. 

'  Tbudicbum,  Journ.  of  Cbem.  Soc.  C2),  Vol.  13,  aud  .Jonrn.  f.  prakt.  Chem.  (N.  F.), 
Bd.  53  ;  Maly,  Wien.  Sitzungsber.,  Bd.  72. 


REACTIONS  FOR  BILEPIOMENTS.  2'65 

Gmelin's  Reaction  for  Bile-pigments.  If  we  carefully  poor  under  a 
eolntion  of  bilirubiii-alkali  in  water  nitric  acid  containing  some  nitrous  acid, 
we  obtain  a  series  of  colored  layers  at  the  juncture  of  the  two  liquids,  in  the 
following  order  from  above  downwards:  green,  blue,  violet,  red,  and  reddish 
yellow.  Tiiis  color  reaction,  Gmelin's  test,  is  very  delicate  and  serves  to 
detect  the  presence  of  one  part  bilirubin  in  80,000  parts  liquid.  The  green 
ring  must  never  be  absent;  and  also  the  reddish  violet  must  be  present  at 
the  same  time,  otherwise  the  reaction  may  be  confused  with  that  for  lutein, 
which  gives  a  blue  or  greenish  ring.  The  nitric  acid  must  not  contain  too 
much  nitrous  acid,  for  then  the  reaction  takes  place  too  quickly  and  it  does 
not  become  typical.  Alcohol  must  not  be  preseiit  in  the  liquid,  because,  as 
is  well  known,  it  gives  a  j)lay  of  colors,  in  green  or  blue,  with  the  acid. 

Hammaksten's  Reaction.  An  acid  is  first  prepared  consisting  of  1  vol. 
nitric  acid  and  19  vols,  hydrochloric  acid  (each  acid  being  about  25^).  One 
volume  of  this  acid  mixture,  which  can  be  kept  for  at  least  a  year,  is,  when 
it  has  become  yellow  by  standing,  mixed  with  4  vols,  alcohol.  If  a  drop  of 
bilirubin  solution  is  added  to  a  few  cubic  centimeters  of  this  colorless  mix- 
ture a  permanent  beautiful  green  color  is  obtained  immediately.  On  the 
further  addition  of  the  acid  mixture  to  the  green  liquid  all  the  colors  of 
Gmelin's  scale,  as  far  as  choletelin,  can  be  produced  consecutively. 

IIuppekt's  Reaction.  If  a  solution  of  bilirubin-alkali  is  treated  with 
milk  of  lime  or  with  calcium  chloride  and  ammonia,  a  precipitate  is  pro- 
duced consisting  of  bilirubin-calcium.  If  this  moist  precipitate,  which  has 
been  washed  with  water,  is  placed  in  a  test-tube  and  the  tube  half  filled 
with  alcohol  which  has  been  acidified,  with  hydrochloric  acid,  and  heated  to 
boiling  for  some  time,  the  liquid  becomes  emerald-green  or  bluish  green  in 
color. 

In  regard  to  the  modifications  of  Gmelin's  test  and  certain  other 
reactions  for  bile-pigments,  see  Chapter  XV  (Urine). 

That  the  characteristic  play  of  colors  in  Gmelin's  test  is  the  result  of 
an  oxidation  is  generally  admitted.  The  first  oxidation  step  is  the  green 
biliverdin.  Then  follows  a  blue  coloring  matter  which  IIeinsius  and 
Campbell  call  hilicyanin  and  Stokyis  calls  cholecyanin,  and  which  shoM's  a 
characteristic  absorption-spectrum.  The  neutral  solutions  of  this  coloring 
matter  are,  according  to  Stokyis,  bluish  green  or  steel-blue  Avith  a  beautiful 
blue  fluorescence.  The  alkaline  solutions  are  green  and  have  no  marked 
fluorescence.  The  alkaline  solutions  show  three  absorption-bands,  one  sharp 
and  dark  in  the  red  between  Cand  D,  nearer  to  C;  a  second,  less  defined, 
covering  D;  and  a  third,  between  E  and  F,  near  E.  The  strongly  acid 
solutions  are  violet-blue  and  show  two  bands,  described  by  Jaffe,  between 
the  lines  C  and  E,  separated  from  each  other  by  a  narrow  space  near  D. 
A  third  band  between  h  and  i^is  seen  with  difficulty.  The  next  oxidation 
step   after   these   blue   coloring   matters   is   a  red   pigment,   and  lastly  a 


236  THE  LIVER. 

yellowish-brown  pigment,  called  clioletelin  by  Maly,  which  in  neutral 
alcoholic  solations  does  not  give  any  absorption  spectrum,  bat  in  acid  solu- 
tion gives  a  band  between  h  and  F.  On  oxidizing,  cliolecyanin  with  lead 
peroxide,  Stokyis  '  obtained  a  product  which  he  calls  clioletelin,  which  is 
quite  similar  to  urinary  urobilin,  to  be  discussed  later. 

Bilirubin  is  best  prepared  from  gall-stones  of  oxen,  these  concretions 
being  very  rich  in  bilirubin-calcium.  The  finely  powdered  concrement  is 
first  exhausted  with  ether  and  then  with  boiling  water,  so  as  to  remove  the 
cholesterin  and  bile-acids.  The  powder  is  then  treated  with  hydrochloric 
acid,  which  sets  free  the  pigment.  Wash  thoroaghly  with  water  and 
alcohol,  dry,  and  extract  repeatedly  with  boiling  chloroform.  After  distill- 
ing the  chloroform  from  the  solution,  treat  the  powdered  residue  with 
absolute  alcohol  to  remove  the  bilifuscin;  dissolve  the  remaining  bilirubin 
in  a  little  chloroform;  precipitate  it  from  this  solution  by  alcohol,  and  do 
this  several  times  if  necessary.  The  bilirubin  is  finally  dissolved  in  boiling 
chloroform  and  allowed  to  crystallize  on  cooling.  The  quantitative  estima- 
tion of  bilirubin  may  be  made  by  the  spectro-photometrical  method,  accord- 
ing to  the  stei:)S  suggested  for  the  blood-coloring  matters. 

Bilivj^rdin,  Cj^Hj^NjO^.  This  body,  which  is  formed  by  the  oxidation 
of  bilirabin,  occurs  in  the  bile  of  many  animals,  in  vomited  matter,  in  the 
placenta  of  the  bitch  (?),  in  the  shells  of  birds'  eggs,  in  the  urine  in  icterus, 
and  sometimes  in  galUstones,  although  in  very  small  quantities.  On  the 
oxidation  of  bile-pigments,  especially  biliverdin,  Kuster  obtained  a 
nitrogeneous  acid,  Uliverdinic  acid,  GJ1J^0^.  On  further  investigation 
of  this  acid  and  its  salts  Kuster  finds  that  on  boiling  the  acid  with  caustic 
soda  or  by  other  basic  bodies,  it  is  readily  transformed  into  the  lactone 
of  the  tribasic  hrematinic  acid  0,11^0^,  with  the  evolution  of  ammonia. 
This  biliverdinic  acid  can  therefore  be  considered  as  the  amid  of  this  last 
acid.  According  to  more  recent  investigations  Kuster' considers  biliver- 
dinic acid  identical  with  his  bibasic  hjematinic  acid,  which  contains  nitrogen. 

Biliverdin  is  amorphous,  at  least  it  has  not  been  obtained  in  well- 
defined  crystals.  It  is  insoluble  in  water,  ether,  and  chloroform  (this  is 
true  at  least  for  the  artificially  prepared  biliverdin),  but  is  soluble  in  alcohol 
or  glacial  acetic  acid,  showing  a  beautiful  green  color.  It  is  dissolved  by 
alkalies,  giving  a  brownish-green  color,  and  this  solution  is  precipitated  by 
acids,  as  well  as  by  calcium,  barium,  and  lead  salts.  Biliverdin  gives 
Huppert's,  Gmelin's,  and  IIammarsten's  reactions,  commencing  with 
the  blue  color.  It  is  converted  into  hydrobilirubin  by  nascent  hydrogen. 
On  allowing  the  green  bile  to  stand,   albo  by  the  action  of  ammonium 

'  Heinsius  and  Campbell,  PflQifer's  Arch.,  Bd.  4;  Stokvis,  Centrnlbl.  f.  d.  mod. 
WissenscL.,  1872,  S.  785;  ibid.,  1873,  S.  211  and  449;  Jiillo,  ibid.,  1868;  Muly,  Wien. 
Sitzungsbur.,  Bd.  59. 

«  Ber.  d.  deutscli.  cbeni.  Gesellscli,,  Bd.  30;  Zeitschr.  f.  physioL  Chem.,  Bd.  2G  ; 
Ber.  d.  deutscb.  chem.  Gesellscb.,  Bd.  32. 


BI LI  VERB  IN.  237 

sulphide,    tlie    biliverdin    niuy    be    reduced    to    Inliruhiu    (IIayciiaft    and 
SCOFIKLI)  '). 

liiliverdiu  is  most  simply  prepared  by  allowing  a  thin  layer  of  an  alkaline 
solution  of  bilfrubin  to  stand  exposed  to  the  air  in  a  dish  until  the  color  is 
brownish  green.  The  solution  is  then  precipitated  by  hydrochloric  acid, 
the  precipitate  washed  with  water  until  no  TICl  reaction  is  obtained,  then 
dissolved  in  alcohol  and  the  pigment  again  separated  by  the  addition  of 
water.  Any  bilirubin  present  nuiy  be  removed  by  means  of  ciiloroform. 
1Il'goni:n(2  and  1  )o vox '  prepared  biliverdin  from  bilirubin  by  the  action 
of  sodium  peroxide  and  a  little  acid. 

BUifusciii,  so  named  by  Stauklku,^  is  an  nmorphous  brown  pigment  soluble  in 
alcnlioland  alkalies,  nearly  insoluble  iu  water  and  ether,  and  soluble  with  great  difficulty 
in  chloroform  (when  bilirubiu  is  not  present  at  tlie  same  time).  When  pure  bilifusciu 
does  not  give  Gmelin's  reaction.  It  is  found  iu  post-mortem  bile  and  gall-stones. 
BiUprtmiii  is  a  green  pigment  inepared  by  Stadelek  from  gall-stones,  which  perhaps  is 
only  a  mixture  of  biliverdin  and  bilirubin.  Dastre  and  Floresco,^  on  the  contrary, 
consider  biliprasin  as  an  intermediate  step  belwien  bilirubin  and  biliverdin.  According 
to  them  it  occurs  as  a  physiological  pigment  in  the  bladder-bile  of  several  animals  and  is 
derived  from  bilirubin  by  oxidation.  Tliis  oxidation  is  brought  about  by  an  oxidation 
ferment  existing  in  the  bile.  BiUlnimin  is  the  name  given  by  IStadei.eu  to  that  brownish 
amorphous  residue  which  is  left  af'er  extracting  gall-stones  with  chloroform,  alcohol, 
and  ether.  It  does  not  give  Gmelin's  test.  Bilicyanin  is  also  found  in  human  gall- 
stones (Heinsius  and  Campbeli,)-  C'/ioloha'mtitin,  so  called  by  MacMunn/Is  a  pigment 
often  occuring  iu  slieep-  and  ox-bile  and  characterized  by  four  absorption-bands,  and 
which  is  formed  from  luematin  by  the  action  of  sodium  uuuilgam.  In  the  dried  condi- 
tion obtained  by  the  evaporaiioi)  of  the  chloroform  soluti(m  it  is  green,  and  iu  alcoholic 
solution  olive-brown. 

Gm?:lin's  and  IIippkrt'.s  reactions  are  generally  used  to  detect  the 
presence  of  bile-pigments  in  animal  fluids  or  tissues.  The  first,  as  a  rule, 
can  be  performed  directly,  and  the  presence  of  proteid  does  not  interfere 
with  it,  but,  on  the  contrary,  it  brings  out  the  play  of  colors  more  strik- 
ingly. If  blood-coloring  matters  are  present  at  the  same  time,  the  bile- 
coloring  matters  are  first  precipitated  by  the  addition  of  sodium  phosphate 
and  milk  of  lime.  This  precipitate  containing  the  bile-pigments  ma}'  be 
used  directly  in  Huppf:rt's  reaction,  or  a  little  of  the  precipitate  may  be 
dissolved  in  IIamm.vrsten's  reagent.  liilirubin  is  detected  in  blood, 
according  to  IIi:i)hNiu.s,°  by  precipitating  the  proteins  by  alcohol,  filtering 
and  acidifying  the  filtrate  with  hydrochloric  or  sulphuric  acid,  and  boiling. 
The  liquid  becomes  of  a  greenish  color.  Serum  and  serous  fluids  may  be 
boiled  directly  with  a  little  acid  after  the  addition  of  alcohol. 

Besides  the  bile-acids  and  bile-pigments  we  have  in  the  bile  also  choles- 
ierin,  lecithin,  palmitin,  stearin,  olein,  and  soaps  of  the  corresponding  /a^^?/ 
acids.  Lassar-Coitn'  has  also  found  myristic  acid  in  ox-bile.  In  some 
animals  the  bile  contains  a  diastatic  enzyme.      Cholin  and  ghjccro-phosjdioric 

'  Centralbl.  f.  Physiol.,  Bd.  3,  S.  222,  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  14. 

*  Arch,  de  Physiol.  (5),  Tome  8. 

*  Cited  from  Hoppe-Seyler,  Physiol,  u.  Path.  chem.  Analyse,  6.  Aufl.,  S.  225. 

*  Arch,  de  Piiysiol.  (5),  Tome  9. 
'  Journ.  of  Physiol.,  Vol.  6. 

*  Upsala  Lilkaref.  Forh.,  Bd.  29,  and  Maly's  Jahresber.,  Bd.  34. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 


238  THE  LIVBR. 

acid,  when  they  are  present,  may  be  considered  as  decomposition  products 
of  lecithin.  Urea  occurs,  though  only  as  traces,  as  a  physiological  con- 
stituent of  human,  ox,  and  dog  bile.  Urea  occurs  in  the  bile  of  the  shark 
and  ray  in  such  large  quantities  that  it  forms  one  of  the  chief  constituents 
of  the  bile.^  The  mineral  constituents  of  the  bile  are,  besides  the  alkalies, 
to  which  the  bile  acids  are  united,  sodium  and  potassium  chloride,  calcium 
and  magnesium  phosphate,  and  iron — 0.04-0,115  p.  m.  in  human  bile, 
chiefly  combined  with  phosphoric  acid  (Young  ^).  Traces  of  copper  are 
habitually  present,  and  traces  of  zinc  are  often  found.  Sulphates  are 
entirely  absent,  or  occur  only  in  very  small  amounts.  • 

The  quantity  of  iron  in  the  bile  varies  greatly.  According  to  Novi 
it  is  dependent  upon  the  kind  of  food,  and  in  dogs  it  is  lowest  with  a  bread 
diet  and  highest  with  a  meat  diet.  According  to  Dastkb  this  is  not  the 
case.  The  quantity  of  iron  in  the  bile  varies  even  though  a  constant  diet 
is  kept  up,  and  the  variation  is  dependent  upon  the  formation  and  destruc- 
tion of  blood.  According  to  Beccari'  the  iron  does  not  disappear  from 
the  bile  in  inanition,  and  the  percentage  shows  no  constant  diminution. 
The  question  as  to  the  extent  of  elimination  by  the  bile  of  the  iron 
introduced  into  the  body  has  received  various  answers.  There  is  no  doubt 
that  the  liver  has  the  property  of  collecting  and  retaining  iron  as  well 
as  other  metals  from  the  blood.  Certain  investigators,  such  as  Novi  and 
KuxKEL,  are  of  the  opinion  that  the  introduced  and  transitorily  retained 
iron  in  the  liver  is  eliminated  by  the  bile,  while  others,  such  as  Hambueger, 
Gottlieb,  and  Anselm,*  deny  any  such  elimination  of  iron  by  the  bile. 

Quantitative  Composition  of  the  Bile.  Complete  analyses  of  human  bile 
have  been  made  by  Hoppe-Seyler  and  his  pupils.  The  bile  was  removed 
as  fresh  as  possible  from  the  gall-bladder  of  cadavers  whose  livers  showed  no 
remarkable  change. 

Older  and  less  complete  analyses  of  human  bile  have  been  made  by 
Frericiis  and  Y.  Gorup-Besanez."  The  bile  analyzed  by  them  was  from 
perfectly  healthy  persons  who  had  been  executed  or  accidentally  killed. 
The  two  analyses  of  Frericiis  are,  respectively,  of  (I)  an  13-year-old  and 
(II)  a  22-year-old  male.     The  analyses  of  v.  Gorup-Besanez  are  of  (I)  a 

'  Hamraersten,  Zeitschr.  f.  physiol.  Cbem.,  Bd.  24. 

^  Journ.  of  Anat.  and  Pliysiol.,  Vol.  5,  p.  158. 

3  Novi,  see  Maly's  Jahresber.,  Bd.  20  ;  Dastre,  Arch,  de  Pliysiol.  (5),  Tome  3  ;  Bec- 
cari,  Arch.  ital.  de  Biol.,  Tome  28. 

■*  Kuiikel,  Pllilger's  Arch.,  Bd.  14  ;  Hambuiger,  Zeitschr.  f.  physio).  Chem.,  Bdd.  2 
and  4;  Gottlieb,  ibid.,  Bd.  15;  Anselm,  "  Ueber  die  Eiscnausscheiduug  der  Galle." 
luaug.-Diss.  Dorpat,  1891.     See  also  the  works  cilcd  in  foot-note  1,  page  176. 

'  See  Hoppe-Seyler,  Physiol.  Chem.,  S.  301  ;  Socoloflf,  Pfliiger's  Arch.,  Bd.  12  ;  Tri- 
fanovvski,  ibid.,  Bd.  9;  Frerichs  in  Hoppe-Seyler's  Physiol.  Chem.,  S.  299;  v.  Gorup- 
Besanez,  ibid. 


COMPOSITION  OF  BILE.  239 

man  of  49  and  (II)  a  woman  of  39.     The  results  are,  as  usual,  in  parts  per 
1000. 

Frerichs.  v.  Gorup-Besanez. 

I.  II.  I.  II. 

Water..: 860.0  859.2  822.7  898.1 

Solids 140.0  140.8  177.3  101.9 

Biliary  suits 72.2  91.4  107.9  56.5 

Mucu.s  and  pigments 26.6  29.8  22.1  14.5 

Cbolesterin 1.6  2.6  >  ,~  „  qa  o 

Fat 3.2  9.2i-  ^^"^  '^^-^ 

Inorganic  substances 6.5  7.7  10.8  6.2 

Hnman  liver-bile  is  poorer  in  solids  than  the  bladder-bile.  In  several 
cases  it  contained  only  12-18  p.  m.  solids,  but  the  bile  in  these  cases  is 
hardly  to  be  considered  as  normal.  Jacobsex  found  22.4-22.8  p.  m. 
solids  in  a  specimen  of  bile.  IIammarsten,'  who  had  occasion  to  analyze 
the  liver-bile  in  seven  cases  of  biliary  fistula,  has  repeatedly  found  25-28 
p.  m.  solids.  In  a  case  of  a  corpulent  woman  the  quantity  of  solids  in  the 
liver-bile  varied  between  30. 10-38. G  p.  m.  in  ten  days. 

Human  bile  sometimes,  but  not  always,  contains  sulphur  in  an  ethereal 
sulphuric-acid-like  combination.  The  quantity  of  such  sulphur  may  even 
amount  to  \-^  of  the  total  sulphur.  Human  bile  is  habitually  richer  in 
glycocholic  than  in  taurocholic  acid.  In  six  cases  of  liver-bile  analyzed  by 
IIammarsten  the  relationship  of  taurocholic  to  glycocholic  acid  varied 
between  1  :  2.07  and  1  :  14.36.  The  bile  analyzed  by  Jacobsen  contained 
no  taurocholic  acid. 

As  example  of  the  composition  of  human  liver-bile  the  following  results 
of  three  analyses  made  by  Hammarstex  are  given.  The  results  are  cal- 
culated in  parts  per  1000. 

Solids 25.200  85.260  25.400 

Water 974  800  964.740  974.600 

Mucin  and  pigments 5  290  4.290  5.150 

Bilesalts 9  3:0  18.240  9.040 

Taurocholate 3.034  2.079  2.180 

Glvoocholate 6.276  16.161  6  860 

Fatty  acids  from  soaps 1.230  1.360  1.010 

Cholestcrin 0.630  1.600  1.500 

Lecithin ]  ^  ^^^  0.574  0.650 

Fat f  "•'■""  0.956  0.610 

Soluble  salts 8  070  6.760  7.250 

Insoluble  salts 0.250  0.490  0.210 

Amongst  the  mineral  constituents  the  chlorine  and  sodium  occur  to  the 
greatest  extent.  The  relationship  between  potassium  and  sodium  varies 
considerably  in  different  biles.  Sulphuric  acid  and  phosplioric  acid  occur 
only  in  very  small  qnantities. 

Bagixsky  and  Sommerfeld  '  have  found  true  mucin,  mixed  with 
some  nucleoalbumin,  in  the  bladder-bile  of  children.  The  bile  contained 
on  an  average  80G.5  p.  m.  water;  103.5  p.  m.  solids;  20  p.  m.  mucin;  9.1 

'  Jacobsen,  Ber.  d.  deutsch.  chem.  GeselLsch.,  Bd.  6;  Hammarsten,  1.  c,  Nova  Act. 
*  Verhaudl.  d.  physiol.  Gesellscb.  zu  Berlin,  1894-95. 


240  THE  LIVER. 

p.  m.  mineral  sabstances;  25.2  p.  m.  bile-salts  (of  wliicli  16.3  p.  m.  were 
glycocholate  and  8.9  p.  m.  taurocholate) ;  3.4  p.  m.  cbolesterin;  6.7  p.  m. 
fat,  and  2.8  p.  m.  leucin. 

The  quantity  of  pigment  in  human  bile  is,  according  to  JSToiiL-PATON, 
0.4-1.3  p.  m.  for  a  case  of  biliary  fistula.  The  method  used  in  determining 
the  pigments  in  this  case  was  not  quite  trustworthy.  More  exact  results 
obtained  by  spectro-photometric  methods  are  on  record  for  dogs'  bile. 
According  to  STADELiiA25"X  '  dogs'  bile  contains  on  an  average  0.6-0.7  p.  m. 
bilirubin.  At  the  most,  only  7  milligrams  pigment  are  secreted  per  kilo  of 
body  in  the  24  hours. 

In  animals  the  relative  proportion  of  the  two  acids  varies  very  much. 
It  has  been  found,  on  determining  the  amount  of  sulphur,  that,  so  far  as 
the  experiments  have  gone,  taurocholic  acid  is  the  prevailing  acid  in  car- 
nivorous mammals,  birds,  snakes,  and  fishes.  Among  the  herbivora  sheep 
and  goats  have  a  predominance  of  taurocholic  acid  in  the  bile.  Ox-bile 
sometimes  contains  taurocholic  acid  in  excess,  in  other  cases  glycocholic  acid 
predominates,  and  in  a  few  cases  the  latter  occurs  almost  alone.  The  bile 
of  the  rabbit,  hare,  and  kangaroo  contains,  like  the  bile  of  the  pig,  almost 
exclusively  glycocholic  acid.  A  distinct  influence  on  the  relative  amounts 
of  the  two  bile-acids  by  different  foods  has  not  been  detected.  Ritter^ 
claims  to  have  found  a  decrease  in  the  quantity  of  taurocholic  acid  in  calves 
when  they  pass  from  the  milk  to  the  plant  diet. 

In  the  above-mentioned  calculation  of  the  taurocholic  acid  from  the 
quantity  of  sulphur  in  the  bile-salts  it  must  be  remarked  that  no  exact  con- 
clusion can  be  drawn  from  this  calculation  as  long  as  we  have  not  investi- 
gated whether  other  kinds  of  bile  contain  sulphur  in  combinations  other 
than  taurocholic  acid,  as  in  human  and  shark  bile. 

The  cholesterin,  which,  according  to  several  investigators,  not  only 
originates  from  the  liver,  but  also  from  the  biliary  passages,  occurs  in  larger 
quantities  in  the  bladder-bile  than  in  the  liver-bile,  and  occurs  to  a  greater 
extent  in  the  non-filtered  than  in  the  filtered  bile  (Doyon  and  Dufoukt^). 

The  gases  of  the  bile  consist  of  a  large  quantity  of  carbon  dioxide,  which 

increases  with  the  amount  of  alkalies,  only  traces  of  oxygen,  and  a  very 

small  quantity  of  nitrogen. 

Little  is  known  in  regard  to  the  propertieft  of  the  bile  in  disease.  The  quantity  of  nrea 
is  found  to  be  considerably  increased  in  uraemia.  Leucin  and  tyrosln  are  observed  in 
acute  yellow  atrophy  of  the  liver  and  in  typhus.  Traces  of  albumin  (without  regard  to 
nncleoalburain)  have  .several  times  been  found  in  the  human  bile.  The  so-called  pig- 
mentary arholia,  or  the  secretion  of  a  bile  containing  bile-acids  but  no  bile-pigments,  has 
also  been  repeatedly  noticed.  In  all  such  cases  observed  by  Ritter  lie  found  a  fatty  de- 
generation of  the   liver-cells,  in   return  for  which,  even  in  excessive  fat  iutiltration, 

'  NoSl-Paton,  Rep.  Lab.  Roy.  Soc.  Coll.  Phys.  Edinburgh,  Vol.  3  ;  Stadelmann,  Der 
Icterus. 

»  Cited  from  Maly's  Jahresber.,  Bd.  6,  S.  195. 
»  Arch,  de  Physiol,  (5),  Tome  8. 


CHEMICAL  FORMATION  OF  BILE.  241 

a  normal  bile  containing  pigments  was  secreted.  Tbe  secretion  of  a  bile  nearly  free 
from  bile-acids  bas  been  observed  by  Hoite-Skyleu  '  in  amyloid  degeneration  of  tbe 
liver.  In  iuiin\!ils,  dogs,  and  especially  rabbits  it  bas  been  olhscrved  tlial  tbe  blood- 
pigniciUs  pass  into  tbe  bile  in  poisoning  and  otber  cases,  causing  a  destruction  of  tbe 
bIood-corpuscle.<",  as  also  after  intravenous  bsemoglobin  injection  (Wertheimer  and 
Meyer,  Fileiink,  Stern'). 

Instead  of  bile  we  sometimes  find  in  the  gall-bladder  under  pathological 
conditions  a  more  or  less  viscous,  thready,  colorless  fluid  which  contains 
psendomiicins  or  other  peculiar  protein  substances.* 

Chemical  Formation  of  the  Bile.  The  first  question  to  be  answered  is 
the  following:  Do  the  specific  constituents  of  the  bile,  the  bile-acids  and 
bile-pigments,  originate  in  the  liver;  and  if  this  is  the  case,  do  they  come 
from  this  organ  only,  or  are  they  also  formed  elsewhere  ? 

The  investigations  of  the  blood,  and  especially  the  comparative  investi- 
gations of  the  blood  of  the  portal  and  hepatic  veins  under  normal  conditions, 
have  not  gi^en  any  answer  to  this  question.  To  decide  this,  therefore,  it 
is  necessary  to  extirpate  the  liver  of  animals  or  isolate  it  from  the  circula- 
tion. If  the  bile  constituents  are  not  formed  in  the  liver,  or  at  least  not 
alone  in  this  organ,  but  only  eliminated  from  the  blood,  then,  after  the 
extirpation  or  removal  of  the  liver  from  the  circulation,  an  accumulation  of 
the  bile  constituents  is  to  be  expected  in  the  blood  and  tissues.  If  the  bile 
constituents,  on  the  contrary,  are  formed  exclusively  in  the  liver,  then  the 
above  operation  naturally  would  give  no  such  result.  If  the  choledochus 
duct  is  tied,  then  the  bile  constituents  will  be  collected  in  the  blood  or 
tissues  whetlier  they  are  formed  in  the  liver  or  elsewhere. 

From  these  principles  Kobner  has  tried  to  demonstrate  by  experiments 
on  frogs  that  the  bile-acids  are  produced  exclusively  in  the  liver.  While  he 
was  unable  to  detect  any  bile-acids  in  the  blood  and  tissues  of  these  animals 
after  extirpation  of  the  liver,  still  he  was  able  to  discover  them  on  tying  the 
choledochus  duct.  The  investigations  of  Ludwig  and  Fleischl*  show 
that  in  the  dog  the  bile-acids  originate  in  the  liver  alone.  After  tying  the 
choledochus  duct  they  observed  that  the  bile  constituents  were  absorbed  by 
the  lymphatic  vessels  of  the  liver  and  passed  into  the  blood  through  the 
thoracic  duct.  Bile-acids  could  be  detected  in  the  blood  after  such  an 
operation,  while  they  could  not  be  detected  in  the  normal  blood.  But 
when  the  choledochus  and  thoracic  ducts  were  both  tied  at  the  same  time, 
then  not  the  least  trace  of  bile-acids  could  be  detected  in  the  blood,  while 


'  Ritter,  Compt.  rend.,  Tome  74,  and  Journ.  de  I'anat.  et  de  la  pbysiol.  (Robin),  1872  ; 
Hoppe-Scyler,  Pbysiol.  Cbem.,  S.  317. 

'  Wertheimer  and  Meyer,  Compt.  rend..  Tome  108;  Filebne,  Virchow's  Arch.,  Bd. 
121  ;  Stern,  ibid.,  Bd.  123. 

'  Winternitz,  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  21. 

*  Kobuer,  see  Heideubain,  Physiologic  dcr  Absonderungsvorgilnge  in  Hermann's 
Handbuch,  Bd.  5  ;  Fleischl,  Arbeiteu  aus  der  pbysiol.  Anstalt  zu  Leipzig,  Jahrgang  9. 


242  TUE  LIVER. 

if  they  are  also  formed  in  other  organs  and  tissnes  they  should  have  been 
present. 

Prom  older  statements  of  Cloez  and  Yulpian,  as  well  as  Yiechow,  the 
hile-acids  also  occur  in  the  suprarenal  capsule.  These  statements  hav^e  not 
been  confirmed  by  later  investigations  of  STADELMAiq"]sr  and  Beier.^  At 
the  jiresent  time  we  have  no  ground  for  supposing  that  the  bile-acids  are 
formed  elsewhere  than  in  the  liver. 

It  has  been  indubitably  proved  that  the  tile-pigments  may  be  formed  in 
other  organs  besides  the  liver,  for,  as  is  generally  admitted,  the  coloring 
matter  hgematoidin,  which  occurs  in  old  blood  extravasations,  is  identical 
with  the  bile-pigments  bilirubin  (see  page  152).  Latschenberger  '  has 
also  observed  in  horses,  under  pathological  conditions,  a  formation  of  bile- 
pigments  from  the  blood-coloring  matters  in  the  tissues.  Also  the  occur- 
rence of  bile-pigments  in  the  jjlacenta  seems  to  depend  on  their  formation, 
in  that  organ,  while  the  occurrence  of  small  quantities  of  bile-pigments  in 
the  blood-serum  of  certain  animals  probably  depends  on  an  absorption  of 
the  same. 

Although  the  bile-pigments  may  be  formed  in  other  organs  besides  the 
liver,  still  it  is  of  first  importance  to  know  what  bearing  this  organ  has  on 
the  elimination  and  formation  of  bile-pigments.  In  this  regard  it  must  be 
recalled  that  the  liver  is  an  excretory  organ  for  the  bile-pigments  circulat- 
ing in  the  blood.  Tarchanoff  has  observed,  in  a  dog  with  biliary  fistula, 
that  intravenous  injection  of  bilirubin  causes  a  very  considerable  increase  in 
the  bile-pigments  eliminated.  This  statement  has  been  confirmed  lately  by 
the  inv^estigations  of  Yossius.^ 

Numerous  experiments  have  been  made  to  decide  the  question  whether 
the  bile-pigments  are  only  eliminated  by  the  liver  or  whether  they  are  also 
formed  therein.  By  experimenting  on  pigeons  Stern  was  able  to  detect 
bile-pigments  in  the  blood-serum  five  hours  after  tying  the  biliary  passages 
alone,  while  after  tying  all  the  vessels  of  the  liver  and  also  the  biliary 
passages  no  bile-pigments  could  be  detected  either  in  the  blood  or  the 
tissues  of  the  animal,  which  was  killed  10-12  hours  after  the  operation. 
Minkowski  and  Naunyn*  have  also  found  that  poisoning  with  arseni- 
uretted  hydrogen  produces  a  liberal  formation  of  bile-pigments  and  the 
secretion,  after  a  short  time,  of  a  urine  rich  in  biliverdin  in  previously 
healthy  geese.     In  geese  with  extirpated  livers  this  does  not  occur. 

No  such  experiments  can  be  carried  out  on  mammalia,  as  they  do  not 
live  long  enough  after  the  operation;  still  there  is  no  doubt  that  this  organ 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18,  iu  which  the  older  literature  may  be  found. 
'  See  Maly's  Jahresber.,  Bd.  10,  and  Monatshefte  f.  Chem.,  Bd.  9. 

*  Tare  h  an  off,  Pflilger's  Arch.,  Bd.  9  ;  Vossius,  cited  from  Sladelmann,  Dcr  Icterus. 

*  Stem,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  19  ;  Minkow.ski  and  Naiinyn,  iUd.,  Bd 
21. 


FORMATION  OF  BILK  ACIDS  AND   riGMENTS.  243 

is  the  cliief  seat  of  tlie  formation  of  bile-pigments  under  physiological  con- 
ditions. 

In  regard  to  the  materials  from  which  the  bile-acids  arc  produced,  it 
may  be  said  with  certainty  that  the  two  components,  glycocoll  and  taurin, 
which  are  both  nitrogenized,  are  formed  from  the  protein  bodies.  In  regard 
to  the  origin  of  the  non-nitrogenized  cholalic  acid,  which  was  formerly 
considered  as  originating  from  the  fats,  we  know  nothing  positively. 

The  blood-coloring  matters  are  considered  as  the  mother-substance  of 
the  bile-pigments.  If  the  identity  of  ha?matoidin  and  bilirubin  w^as  settled 
beyond  a  doubt,  then  this  view  might  be  considered  as  proved.  Independ- 
ently, however,  of  this  identity,  which  is  not  admitted  by  all  investigators, 
the  view  that  the  bile-pigments  are  derived  from  the  blood-coloring  matters 
has  strong  arguments  in  its  favor.  It  has  been  shown  by  several  experi- 
menters that  a  yellow  or  yellowish-red  pigment  can  be  formed  from  the 
blood-coloring  matters,  Avhich  gives  Gmelix's  test,  and  which,  though  it 
may  not  form  a  complete  bile-jiigment,  is  at  least  a  step  in  its  formation 
(Latschenberger).  a  further  proof  of  the  formation  of  the  bile-pigments 
from  the  blood-coloring  matters  consists  in  the  fact  that  ha^matin  yields 
urobilin,  which  is  identiciil  with  hydrobilirubin,  on  reduction  (see  Cha2)ter 
XV).  Further,  ha?matoporphyrin  (see  page  151)  and  bilirubin  are  isomers, 
according  to  NE^x•KI  and  Sierer,  and  nearly  allied.  The  formation  of 
bilirubin  from  the  blood-coloring  matters  is  shown,  according  to  the  obser- 
vations of  several  investigators,'  by  the  appearance  of  free  hemoglobin  in 
the  plasma — produced  by  the  destruction  of  the  red  corpuscles  by  Avidely 
differing  inlluences  (see  below)  or  by  tlie  injection  of  haemoglobin  solution 
— causing  an  increased  formation  of  bile-pigments.  The  amount  of  pig- 
ments in  the  bile  is  not  only  considerably  increased,  but  the  bile-pigments 
may  even  pass  into  the  urine  under  certain  circumstances  (icterus).  After 
the  injection  of  haemoglobin  solution  into  a  dog  either  subcntaneously  or  in 
the  peritoneal  cavity,  Stadelmann  and  Gorodecki^  observed  in  the  secre- 
tion of  pigments  by  the  bile  an  increase  of  Gl'^,  which  lasted  for  more  than 
twenty-four  hours. 

If,  then,  iron-free  bilirubin  is  derived  from  the  hfematin  containing  iron, 
then  iron  must  be  split  off.  This  process  may  be  represented  by  the  follow- 
ing formula,  according  to  Xencki  and  Sieber  :'  Cj^Hj^N^O.Fe  -f  •2H,0— Fe 
=  2C,,n,jXjO,.  The  question  in  what  form  or  combination  the  iron  is 
split  off  is  of  special  interest,  and  also  whether  it  is  eliminated  by  the  bile. 
This  latter  dges  not  seem  to  be  the  case.  In  100  parts  of  bilirubin  which 
are  eliminated  by  the  bile  there  are  only  1.4-1.5  parts  iron,  according  to 

'  See  Stadelmann,  Der  Icterus,  etc.     Stuttgart,  1891, 

'  See  Stadelmann,  ibid. 

3  Arch.  f.  exp.  Path.  u.  Pbarm.,  Bd.  24,  S.  440. 


244  THE  LIVER. 

KuNKEL;  wliile  100  parts  hasmatin  contain  abont  9  j)arts  iron.  Minkowski 
and  ]>ASEiiix "  have  also  found  that  the  abundant  formation  of  bile-pigments 
occnrring  in  jDoisoning  by  arseninretted  hydrogen  does  not  increase  the 
qnantity  of  iron  in  the  bile.  The  quantity  apparently  does  not  correspond 
with  that  in  the  decomposed  blood-coloring  matters.  It  follows  from  the 
researches  of  several  investigators'^  that  the  iron  is,  at  least  chiefly,  retained 
by  the  liver  as  a  ferrnginons  pigment  or  protein  substance. 

What  relationship  does  the  formation  of  bile-acids  bear  to  the  formation 
of  bile-pigments?  Are  these  two  chief  constituents  of  the  bile  derived 
simultaneously  from  the  same  material,  and  can  we  detect  a  certain  connec- 
tion between  the  formation  of  bilirubin  and  bile-acids  in  the  liver  ?  The 
investigations  of  SxADELMAis^isr  teach  us  that  this  is  not  the  case.  With 
increased  formation  of  bile-pigments  the  bile-acids  decrease  and  the  supply 
of  haemoglobin  to  the  liver  acts  in  strongly  increasing  the  formation  of 
bilirubin,  but  simultaneously  strongly  decreases  the  production  of  bile- 
acids.  According  to  STADELMAisrisr  the  formation  of  bile-pigments  and 
bile-acids  is  due  to  a  special  activity  of  the  cells. 

Accbrding  to  the  researches  of  Puglise  '  the  spleen  has  the  property  of 
retaining  bodies  necessary  for  the  preparation  of  the  bile-pigments  in  the 
liver  and  gradually  transferring  them  to  the  liver  through  the  portal  vein. 
On  the  extirpation  of  the  spleen  these  bodies  must  be  deposited  in  other 
organs,  namely,  the  marrow,  and  then  passes  to  the  liver  through  the  great 
circulation.  On  removing  the  spleen  the  secretion  cf  bile-pigments 
diminishes  to  even  less  than  one  half.  The  spleen  extirpation  does  not 
otherwise  exercise  any  iiifl nance  on  the  specific  gravity  of  the  bile  or  the 
percentage  of  solids  and  bodies  soluble  in  alcohol. 

An  absorption  of  bile  from  the  liver  and  the  passage  of  the  bile  con- 
stituents into  the  blood  and  urine  occurs  in  retarded  discharge  of  the  bile, 
and  usually  in  different  forms  of  hepatogenic  icterus.  But  bile-pigments 
may  also  pass  into  the  urine  under  other  circumstances,  especially  in 
animals  where  a  solution  or  destruction  of  the  red  blood-corpuscles  takes 
plac3  through  injection  of  water  or  a  solution  of  biliary  salts,  through 
poisoning  by  ether,  chloroform,  arseninretted  hydrogen,  phosphorus,  or 
toluyltiidiamin;  and  in  other  cases.  This  occurs  also  in  man  in  grave 
infectious  diseases.  We  have  therefore  a  second  form  of  icterus,  in  which 
the  blood-coloring  matters  are  transformed  into  bile-pigments  elsewhere 
than  in  the  liver,   namely,  in  the  blood — a  liannaiogenic  or  anliepatogenic 


'  Kunkel,  Pfll'iger's  Arch.,  Bd.  14  ;  ]\Iiiikouski  and  Baseriii,  Arcli.  f.  exp.  Path.  u. 
Pharm.,  Bd.  23. 

'  SeeNaunyn  and  Minkowski,  Arch.  f.  cxp.  Patli.  u.  Pharm.,  Bd.  21;  Liitscheiiberger, 
1.  c. ;  Neumann,  Viichow'.s  Arch.,  Bd.  HI,  aud  the  literature  in  foot-note  3,  p.  207. 

*  Du  Bois-Reymond'3  Arch.,  1899. 


BILE  CONCRETIONS.  245 

icterus.  The  occurrence  of  a  liaematogenic  icterns  has  been  made  very 
probable  by  the  important  investigations  of  Minkowski  and  Naunyn, 
Ar.vNAssiEW,  SiLHEKMAXX,  and  especially  Stadelmaxn.  '  This  statement 
lias  been  confirmed  in  certain  of  the  above-mentioned  cases,  as  after  poi- 
soiling  with  phosphorus,  toluylendiamin,  and  arseniurettcd  hydrogen,  by 
direct  experiment. 

The  icterus  is  also  in  these  cases  hepatogenic ;  it  depends  upon  an  absorp- 
tion of  bile-pigments  from  the  liver,  and  this  absorption  seems  to  originatt*^ 
in  the  ditTerent  cases  in  somewhat  different  Avays.  Thus  the  bile  may  be 
•viscous  and  cause  a  stowing  of  the  bile  by  counteracting  the  low  secretion 
pressure.  In  other  cases  the  fine  biliary  passages  may  be  compressed  by  an 
abnormal  swelling  of  the  liver-cells,  or  a  catarrh  of  the  bile-passages  may 
occur  causing  a  stowage  of  the  bile  (Stadelmann). 

Bile  Concretions. 

The  concrements  which  occur  in  the  gall-bladder  vary  considerably  in 
size,  form,  and  number,  and  are  of  three  kinds,  depending  upon  the  kind 
and  nature  of  the  bodies  forming  thei"  chief  mass.  One  group  of  gall- 
stones contains  lime-pigment  as  chief  constituent,  the  other  cholesterin,  and. 
the  third  calcium  carbonate  and  phosphate.  The  concrements  of  the  last- 
mentioned  group  occur  very  seldom  in  man.  The  so-called  cholesterin 
stones  are  those  which  occur  most  frequently  in  man,  while  the  lime-pigment 
atones  are  not  found  very  often  in  man,  but  often  in  oxen. 

The  pigme7ii-siones  are  generally  not  large  in  man,  but  in  oxen  and  pigs 
they  are  sometimes  found  the  size  of  a  walnut  or  even  larger.  In  most 
cases  they  consist  chiefly  of  bilirubin-calcium  with  little  or  no  biliverdin. 
Sometimes  also  small  black  or  greenish-black,  metallic-looking  stones  are 
found,  which  consist  chiefly  of  bilifuscin  along  with  biliverdin.  Iron  and 
copper  seem  to  be  regular  constituents  of  pigment-stones.  Manganese  and 
zinc  have  also  been  found  in  a  few  cases.  The  pigment-stones  are  generally 
heavier  than  water. 

The  chohsterin-stones,  whose  size,  form,  color,  and  structure  may  vary 
greatly,  are  often  lighter  than  water.  The  fractured  surface  is  radiated, 
crystalline,  and  frequently  shows  crystalline,  concentric  layers.  The 
cleavage  fracture  is  waxy  in  appearance,  and  the  fractured  surface  when 
rubbed  by  the  nail  also  becomes  like  wax.  By  rubbing  against  each  other 
in  the  gall-bladder  they  often  become  faceted  or  take  other  remarkable 
shapes.  Their  surface  is  sometimes  nearly  white  aiid  waxlike,  but  generally 
their  color  is  variable.  They  are  sometimes  smooth,  in  other  cases  they  are 
rough  or  uneven.     The  quantity  of  cholesterin  in  the  stones  varies  from 

'  The  literature   belonging  to  this  subject  is  found  in  Stadelmanu,  Der  Icterus,  etc 
Stuttgart,  1891. 


246  THE  LIVER. 

642-981  p.  m.  (Ritter').  The  cliolesterin-stones  also  sometimes  contain 
variable  amounts  of  lime-pigments  which  give  them  a  very  cliangeable 
appearance. 

Cholesterin.  This  body  is  generally  considered  as  a  monovalent  alcohol 
of  the  formula  C^,II„.OH.  According  to  recent  investigations  it  has  been 
shown  that  the  molecule  contains  27  atoms  of  carbon.  The  formula  is 
either  C„H,^OH  (Obermuller)  or  C^^H^jOH  (Mauthjster  and  Suida). 
By  the  action  of  concentrated  sulphuric  acid  or  phosphoric  acid,  but  also  in 
other  ways,  hydrocarbons  are  obtained,  which  are  called  cholesterilin, 
cholesiero)i,  and  cliolesterilene  (Zwenger,  Walitzky,  and  others).  Mauth- 
NER  and  SuiDA,*  who  have  closely  studied  these  hydrocarbons,  have  been 
able  to  prepare  a  crystalline  cholesterlin  by  heating  cholesterin  with 
anhydrous  copper  sulphate.  On  oxidation  cholesterin  yields  partly  indif- 
ferent and  partly  acid  products,  which  seem  to  indicate  a  close  relationship 
between  cholesterin  and  cholalic  acid.  The  hydrocarbons  stand,  according 
to  Wetl,'  in  close  connection  with  the  terpene  group. 

Cholesterin  occurs  in  small  amounts  in  nearly  all  animal  JBuids  and 
juices.  /  It  occurs  only  rarely  in  the  urine,  and  then  in  very  small  quanti- 
ties. It  is  also  found  in  the  different  tissues  and  organs — especially 
abundant  in  the  brain  and  the  nervous  system, — further  in  the  yolk  of  the 
egg^  in  semen,  in  wool-fat  (together  with  isocholesterin),  and  in  sebum.  It 
appears  also  in  the  contents  of  the  intestine,  in  excrements,  and  in  the 
meconium.  It  occurs  pathologically  especially  in  gall-stones,  as  well  as  in 
atheromatous  cysts,  in  pus,  in  tuberculous  masses,  old  transudations,  cystic 
fluids,  sputum,  and  tumors.  It  does  not  exist  free  in  all  cases;  for  exam- 
ple, it  exists  in  part  as  fatty  acid  esters  in  wool-fat,  blood,  and  brain. 
Several  kinds  of  cholesterin,  called  phytosteriues,  have  been  found  in  the 
plant  kingdom. 

Cholesterin  which  crystallizes  from  warm  alcohol  on  cooling,  and  that 
which  is  present  in  old  transudations,  contains  1  mol.  of  water  of  crystalliza- 
tion, melts  at  145°  C,  and  forms  colorless,  transparent  plates  whose  sides 
and  angles  frequently  appear  broken  and  whose  acute  angle  is  often  7G°  30' 
or  S?*^  30'.  In  large  quantities  it  appears  as  a  mass  of  white  plates  which 
shine  like  mother-of-pearl  and  have  a  greasy  feel. 

Cholesterin  is  insoluble  in  water,  dilute  acids  and  alkalies.  It  is  neither 
dissolved  nor  changed  by  boiling  caustic  alkali.  It  is  easily  soluble  in  boil- 
ing alcohol,   and   crystallizes  on   cooling.     It   dissolves   readily  in   ether. 


'  Journ.  de  I'anat.  et  de  la  pbysiol.  (Robiu),  1872. 

'^  Obermiiller,  Dn  Bois-Ileymond's  Arch.,  1889,  and  Zeitschr.  f.  pbysiol.  Chem.,  Bd. 
lo  ;  Mantbner  and  Suida,  Wien.  Sitzuugsber.,  Math.  Nat.  Classe,  Bd.  103,  Abtb.  2b, 
which  also  contains  the  older  literature. 

»  Du  Bois-Reyraond's  Arch.,  188G,  S.  182. 


CUOLESTEIilN.  247 

chloroform,  and  benzol,  and  also  in  the  volatile  or  fatty  oils.  It  is  dissolved 
to  a  slight  extent  by  alkali  salts  of  the  bile-acids. 

Among  the  many  combinations  of  cholesterin  studied  by  Obermuller, 
the  propionic  ester,  CJI^.  CO.O.C^II,,,  is  of  special  interest  because  of  the 
behavior  of  the  fused  combination  on  cooling,  and  is  used  in  the  detection  of 
cholesterin.  For  the  detection  of  cholesterin  we  make  use  of  its  reaction 
with  concentrated  sulphuric  acid,  which  gives  colored  products. 

If  a  mixture  of  live  parts  sulphuric  acid  and  one  part  water  acts  on  a 
cholesterin  crsytal,  this  crystal  will  show  colored  rings,  first  a  bright 
carmine-red  and  then  violet.  Tliis  fact  is  made  use  of  in  the  microscopic 
detection  of  cholesterin.  Another  test,  and  one  very  good  for  the  micro- 
scopical detection  of  cholesterin,  consists  in  treating  the  crystals  first  with 
the  above  dilute  acid  and  then  with  some  iodine  solution.  The  crystals  will 
be  gradually  colored  violet,  bluish  green,  and  a  beautiful  blue. 

Salkowski's  '  Reaction. — The  cholesterin  is  dissolved  in  chloroform 
and  then  treated  with  an  equal  volume  of  concentrated  sulphuric  acid. 
The  cholesterin  solution  becomes  first  bluish  red,  then  gradually  more 
violet-red,  while  the  sulphuric  acid  appears  dark  red  with  a  greenish 
fluorescence.  If  the  chloroform  solution  is  poured  into  a  porcelain  dish  it 
becomes  violet,  then  green,  and  finally  yellow. 

LiEBERiiANN-BuRCHARD's  *  Reaction. — Dissolve  the  cholesterin  in  about 
U  c.c.  chloroform  and  add  first  10  drops  acetic  anhydride  and  then  concen- 
trated siilphuric  acid  drop  by  drop.  The  color  of  the  mixture  Avill  first  be  a 
beautiful  red,  then  blue,  and  finally,  if  not  too  much  cholesterin  or  sulphuric 
acid  is  present,  a  permanent  green.  In  the  presence  of  very  little  cholesterin 
the  green  color  may  appear  immediately. 

Pure,  dry  cholesterin  when  fused  in  a  test-tube  over  a  low  flame  with  two  to  three 
drops  propionic  anhydride  yields  a  mass  which  on  cooling  is  first  violet,  tiien  blue, 
green,  orange,  carmine  red,  and  finally  copper-red.  It  is  best  to  re-fuse  the  mass  on  a 
glass  rod  and  then  to  observe  the  rod  on  cooling,  holding  it  against  a  dark  background 
(Ohkumijlleu). 

ScniPF's  Redction.  If  a  little  cholesterin  is  placed  in  a  porcelain  dish  with  the  addi- 
tion of  a  few  drops  of  a  mixture  of  two  to  three  vols.  cone,  hydrochloric  acid  or  sul- 
phuric acid  and  one  vol.  of  a  medium  solution  of  ferric  chloride,  and  carefully  evapo- 
rated to  dryness  bver  a  small  flame,  a  reddish-violet  residue  is  first  obtained  and  then  a 
bluish  violet. 

If  a  small  quantity  of  cholesterin  is  evaporated  to  dryness  with  a  drop  of  concen- 
trated nitric  acid,  we  obtain  a  yellow  spot  which  becomes  deep  orauge-rtd  with  am- 
monia or  caustic  soda  (not  a  characteristic  reaction). 

Koprosterin  is  tlie  name  given  by  Bondzvnskt  for  the  cholesterin  Isolated  by  him 
from  iiunian  f;pcea,  Avliich  was  prepared  earlier  by  Flint  ^  and  designated  xti  vrorin.  It 
dissolves  in  cold,  absolute  alcohol  and  very  readily  in  ether,  chloroform,  and  benzol. 
It  crystallizes  in  fine  needles  which  melt  at  95-96°  C.  and  is  dextro-rotatory,  a(D)  =  4-  24. 

*  Pfliiger's  Arch.,  Bd.  6. 

*  C.  Liebermann,  Ber.  d.  deutscb.  chem.  Gesellsch.,  Bd.  18,  S.  1804,-  H.  Burchard, 
Beitrilge  zur  Kenntniss  der  Cholesterine.     Rostock,  1889. 

*  Bondzynski,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  29;  Bondzynski  and  Hum- 
nicki,  Zeitschr.  f.  physiol.  Chem.,  Bd.  22;  Flint,  ibid.,  Bd.  23,  and  Amer.  Journ.  Med. 
Sciences,  1863. 


248  THE  LIVER. 

It  gives  the  same  color  reactions  as  cholesteiiii,  with  the  exception  that  it  does  not  give  a 
reaction  witli  propionic  anhydride.  According  to  Bondztnski  and  Humnicke  it  is  a 
dibydrocholesterin,  with  the  formula  CnH^nO,  which  is  derived  in  the  human  intestine 
by  the  reduction  of  ordinary  cholesterin.  These  investigators  have  found  another  cho- 
lesterin,  liippokoprostcrin,  with  the  formula  C27H54O,  in  horses'  faeces. 

Isocholesterin  is  a  cliolesteriu,  so  called  by  Schulze/  with  tlie  formnla 
CjgH^jOH,  which  occurs  in  wool-fat  and  is  therefore  found  to  a  great 
extent  in  so-called  lanolin.  It  does  not  give  Salkows-ki's  reaction.  It 
melts  at  138-138.5°  C. 

"We  make  use  of  the  so-called  cholesterin-stones  in  the  preparation  of 
cholesterin.  The  powder  is  first  boiled  with  water  and  then  repeatedly- 
boiled  with  alcohol.  The  cholesterin  which  on  cooling  separates  from  the 
warm  filtered  solution  is  boiled  with  a  solution  of  caustic  potash  in  alcohol  so 
as  to  saponify  any  fat.  After  the  evaporation  of  the  alcohol  we  extract  the 
cholesterin  from  the  residue  with  ether,  by  which  the  soaps  are  not  dis- 
solved, filter,  evaporate  the  ether,  and  purify  the  cholesterin  by  recrystal- 
lization  from  alcohol-ether.  The  cholesterin  may  be  extracted  from  tissues 
and  fluids  by  first  extracting  with  ether  and  then  purifying  as  above.  It  is 
detected  and  determined  quantitatively  in  tissue,  etc.,  by  this  same  method. 
It  is  ordinarily  easily  detected  in  transudations  and  pathological  formations 
by  means'of  the  microscope. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  6;  Journal  f.  prakt.  Chem.,  N.  F.,  Bd.  25, 
S.  458  ;  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  14,  S.  533.  See  also  E.  Schulze  and  J. 
Barbieri,  Journal  f.  prakt.  Chem.,  N.  F.,  Bd.  25,  S.  159.  In  regard  to  the  formula  for 
isocholesterin,  see  Darmstadter  and  Lifschutz,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd. 
31,  and  E.  Schulze,  ibid.,  S.  1300. 


CHAPTER  IX. 

DIGESTION. 

The  purpose  of  the  digestion  is  to  separate  those  constitnents  of  the 
food  whicli  serve  as  the  nutriment  of  the  body  from  those  wliich  are  useless, 
and  to  separate  eacli  in  such  a  form  that  it  may  be  taken  up  by  the  blood 
from  the  alimentary  canal  and  employed  for  the  various  purposes  in  the 
organism.  This  demands  not  only  mechanical  but  also  chemical  action. 
The  first  action,  which  is  essentially  dependent  upon  the  piiysical  properties 
of  the  food,  consists  in  a  tearing,  cutting,  crushing,  or  grinding  of  the  food, 
and  serves  chiefly  to  convert  the  nutritive  bodies  into  a  soluble  and  easily 
absorbed  form,  or  in  the  splitting  of  the  same  into  simpler  combinations  for 
use  in  the  animal  syntheses.  The  solution  of  the  nutritive  bodies  may  take 
place  in  certain  cases  by  the  aid  of  water  alone,  but  in  most  cases  a  chemical 
metamoriihosis  or  cleavage  is  necessary,  and  is  effected  by  means  of  the  acid 
or  alkaline  fluids  secreted  by  the  glands.  The  study  of  the  processes  of 
digestion  from  a  chemical  standpoint  must  therefore  begin  with  the  din-es- 
tive  fluids,  their  qualitative  and  quantitative  composition,  as  well  as  their 
action  on  the  nutriments  and  foods. 

I.  The  Salivary  Glands  and  the  Saliva. 

The  salivary  glands  are  partly  albwninous  gla?ids  (as  tlie  parotid  in  man 
and  mammals  and  the  submaxillary  in  rabbits),  partly  mncons  glands  (as 
some  of  the  small  glands  in  the  buccal  cavity  and  the  sublingual  and  sub- 
maxillary glands  of  many  animals),  and  partly  mixed  glands  (as  the 
submaxillary  gland  in  man).  The  alveoli  of  the  albumin-glands  contain 
cells  which  are  rich  in  proteid,  but  contain  no  mucin.  The  alveoli  of  the 
mucin-glands  contain  cells  rich  in  mucin  but  poor  in  proteid.  Cells 
arranged  in  different  ways,  but  rich  in  proteids,  also  occur  in  the  submaxil- 
lary and  sublingual  glands.  According  to  the  analyses  of  Oidtmann  '  the 
salivary  glands  of  a  dog  contain  790  p.  m.  water,  200  p.  m.  organic  and  10 
p.  m.  inorganic  solids. 


'  Cit.    from   Gonip-Besatiez.   Lehrbiich  d.   physiol.   Cliem.,   4.   Aufl.,   8.   732.     The 
figures  there  given  aniouut  to  1010  parts  iuslead  of  1000  parts. 

249 


250  DIQESTION. 

Among  the   solids  we  find  micc{7i,  2^'>'oteids,    nucleoproteids,   nuclein, 

enzymes  and  their  zymogens^  besides  extractive  bodies^  leucin,  xanthm  bodies^ 

and  mineral  substances. 

The  occurrence  of  a  mucinogen  has  not  been  proved.  On  the  complete  removal  of 
all  mucin  E.  Holmgren  ^  found  no  mucinogen  in  the  submaxillary  gland  of  the  ox,  but 
a  muciu-like  glyconucleoproteid. 

The  saliva  is  a  mixture  of  the  secretion  of  the  above-mentioned  groups 
of  glands;  therefore  it  is  proper  that  we  first  study  each  of  the  different 
secretions  by  itself,  and  then  the  mixed  saliva. 

The  submaxillary  saliva  in  man  may  be  easily  collected  by  introducing 
a  canula  through  the  papillary  opening  into  Wharton's  duct. 

The  submaxillary  saliva  has  not  always  the  same  composition  or  proper- 
ties; this  depends  essentially,  as  shown  by  experiments  on  animals,  upon 
the  conditions  under  which  the  secretion  takes  place.  That  is  to  say,  the 
secretion  is  partly  dependent  on  the  cerebral  system,  through  the  facial 
fibres  in  the  chorda  tympani  and  partly  on  the  sympathetic  nervous  system, 
through  the  fibres  entering  the  vessels  in  the  gland.  In  consequence  of  this 
dependence  the  two  distinct  varieties  of  submaxillary  secretion  are  distin- 
guishec]/  as  chorda-  and  sympathetic  saliva.  A  third  kind  of  saliva,  the 
so-called  jmralytic  saliva,  is  secreted  after  poisoning  with  curara  or  after  the 
severing  of  the  glandular  nerves. 

The  difference  between  chorda-  and  sympathetic  saliva  (in  dogs)  consists 
chiefly  in  their  quantitative  constitution,  namely,  the  less  abundant  sym- 
pathetic saliva  is  more  viscous  and  richer  in  solids,  especially  in  mucin, 
than  the  more  abundant  chorda-saliva.  The  specific  gravity  of  the  chorda- 
saliva  of  the  dog  is  1.0039-1.0056  and  contains  12-14  p.  m.  solids 
(EcKHAKD ').  The  sympathetic  has  a  specific  gravity  of  1.0075-1.018,  with 
16-28  p.  m.  solids.  The  gases  of  the  chorda-saliva  have  been  investigated 
by  Pfluger.'  He  found  0.5-0.8^  oxygen,  0.9-1^  nitrogen,  and  64.73- 
85.13^  carbon  dioxide — all  results  calculated  at  0°  C.  and  760  mm.  pressure. 
The  greater  part  of  the  carbon  dioxide  was  chemically  combined. 

The  two  kinds  of  submaxillary  secretion  just  named  have  not  thus  far 
been  separately  studied  in  man.  The  secretion  may  be  excited  by  a  moral 
emotion,  by  mastication,  and  by  irritating  the  mucous  membrane  of  the 
month,  especially  with  acid-tasting  substances.  The  submaxillary  saliva  in 
man  is  ordinarily  clear,  rather  thin,  a  little  ropy,  and  froths  easily.  Its 
reaction  is  alkaline.  The  specific  gravity  is  1.002-1.003,  and  it  contains 
3,6-4.5  p.   m.  solids.*     We  find  as  organic  constituents  mucin,   traces  of 

»  Upsala  Lilkaref.  Forh.  (N.  F.),  Bd.  2;  also  Maly's  Jahresber.,  Bd.  27. 
»  Cited  from  Kuhne,  Lehrb.  d.  physiol.  Chem.,  S.  7. 
"Pfliiger's  Arch.,  Bd.  1. 

*  See  Maly,  "  Chemie  der  Verdauungssilfte  und  der  Verdauung"  in  Hermann's 
Handb.,  Bd.  5,  Th.  2,  S.  18.     This  article  contains  also  the  pertinent  literature. 


SALIVA.  251 

proteid  and  diastatic  enzyme,  which  is  absent  in  several  species  of  animals. 
The  inorganic  bodies  are  alkali  chlorides,  sodium  and  magnesium  phos- 
phates, besides  bicarbonates  of  the  alkalies  and  calcium.  Potassium  sulpho- 
''vanide  occurain  this  saliva. 

The  Sublingual  Saliva.  The  secretion  of  this  saliva  is  also  influenced 
by  the  cerebral  and  the  sympathetic  nervous  system.  The  chorda-saliva, 
which  is  secreted  only  to  a  small  extent,  contains  numerous  salivary  corpus- 
cles, but  is  otherwise  transparent  and  very  ropy.  Its  reaction  is  alkaline 
and  contains,  according  to  Heidenhain,'  27.5  p.  m.  solids  (in  dogs). 

The  sublingual  secretion  in  man  is  clear,  mucilaginous,  more  alkaline 
than  the  submaxillary  saliva,  and  contains  mucin,  diastatic  enzyme,  and 
potassium  snlphocyanide. 

Buccal  mucus  can  only  be  obtained  p.. re  from  animals  by  the  method 
suggested  by  Bidder  and  Schmidt,  which  consists  in  tying  the  exit  to  all 
the  large  salivary  glands  and  cutting  off  their  secretion  from  the  mouth. 
The  quantity  of  liquid  secreted  under  these  circumstances  (in  dogs)  was  so 
very  small  that  the  investigators  named  were  able  to  collect  only  2  grms. 
buccal  mucus  in  the  course  of  twenty-four  hours.  It  is  a  thick,  ropy, 
sticky  liquid  containing  mucin;  it  is  rich  in  form-elements,  above  all  in  flat 
epithelium-cells,  mucous  cells,  and  salivary  corpuscles.  The  quantity  of 
solids  in  the  buccal  mucus  of  the  dog  is,  according  to  Bidder  and 
Schmidt,"  0.98  p.  m. 

Parotid  Saliva.  The  secretion  of  this  saliva  is  also  partly  dependent  on 
the  cerebral  nervous  system  (n.  glossopharyngeus)  and  partly  on  the 
sympathetic.  The  secretion  may  be  excited  by  mental  emotions  and  by 
irritation  of  the  glandular  nerves,  either  directly  (in  animals)  or  reflexly,  by 
mechanical  or  chemical  irritation  of  the  mucous  membrane  of  the  mouth. 
Among  the  cliemical  irritants  the  acids  take  first  place,  while  alkalies  and 
pungent  substances  have  little  action.  Sweet-tasting  bodies,  such  as  honey, 
are  said  to  have  no  effect.  Mastication  has  great  influence  in  the  seretion 
of  parotid  saliva,  which  is  especially  marked  in  certain  herbivora. 

Unman  parotid  saliva  may  be  readily  collected  by  the  introduction  of  a 
canula  into  Stensox's  duct.  This  saliva  is  thin,  less  alkaline  than  the 
submaxillary  saliva  (the  first  drops  are  sometimes  neutral  or  acid),  without 
special  odor  or  taste.  It  contains  a  little  proteid  but  no  mucin,  which  is  to 
be  expected  from  the  construction  of  the  gland.  It  also  contains  a  diastatic 
enzyme,  which,  however,  is  absent  in  many  animals.  The  quantity  of  solids 
varies  between  5  and  16  ji.  m.  The  specific  gravity  is  1.003-1.012. 
Potassium  snlphocyanide  seems  to  be  present,  though  it  is  not  a  constant 
constituent.     Kulz  '  found  1.4G^  oxygen,  3.2^  nitrogen,  and  in  all  66.7^ 

'  Studieii  d.  physiol.  Instituts  zu  Breslau,  Heft  4. 

*  Die  Verdauungssilfte  und  der  Stoffwechsel  (Mitau  and  Leipzig,  1852),  S.  5. 

'  Zeitschr.  f.  Biolosrie,  Bd.  23, 


252  BIOESTION. 

carbon  dioxi(£e  in  human  parotid  saliva.     The  quantity  of  firmly  combined 
carbon  cKoxide  was  G2^. 

The  mixed  buccal  saliva  in  man  is  a  colorless,  faintly  opalescent,  slightly 
ropy,  easily  frothing  liquid  without  special  odor  or  taste.  It  is  made  turbid 
by  epithelium-cells,  mucous  and  salivary  corpuscles,  and  often  by  food 
residues.  Like  the  sabmaxillary  and  parotid  saliva,  on  exposure  to  the  air 
it  becomes  coyered  with  an  incrustation  consisting  of  calcium  carbonate  and 
a  small  quantity  of  an  organic  substance,  or  it  gradually  becomes  cloudy. 
Its  reaction  is  generally  alkaline  to  litmus,  and  according  to  Chittenden" 
and  Ely  it  corresponds  to  the  alkalinity  of  a  0.8  p.  m.  ISra^OOj  solution. 
Still  the  alkalinity  varies  (Chittenden  and  Kichards)  and  may  also  be 
acid,  as  found  by  Stricker  '  to  be  the  case  some  time  after  a  meal.  The 
specific  gravity  varies  between  1.002  and  1.008,  and  the  quantity  of  solids 
between  5  and  10  p.  m.  The  solids,  irrespective  of  the  form-constituents 
mentioned,  consist  of  proteid,  mucin,  two  enzymes,  ptyaUii  and  glucase,  and 
mineral  bodies.  It  is  also  claimed  that  urea  is  a  normal  constituent  of  the 
saliva.  The  mineral  bodies  are  alkali  chlorides,  bicarbonates  of  the  alkalies 
and  calcium,  phosphates,  and  traces  of  sulphates,  nitrites,  and  sulpho- 
cyanide^  (0.1  p.  m.  Munk)  and  ammonia.  Kruger^  has  recently  shown 
that  the  saliva  from  smokers  contains  more  sulphocyanides  than  that  from 
non-smokers. 

Sulphocyanides,  which,  although  not  constant,  occur  in  the  saliva  of 
man  and  certain  animals,  may  be  easily  detected  by  first  acidifying  the 
saliva  with  hydrochloric  acid  and  treating  with  a  very  dilute  solution  of 
ferric  chloride.  As  control,  especially  in  the  presence  of  very  small  quan- 
tities, it  is  best  to  compare  the  test  with  another  test-tube  containing  an 
equal  amount  of  acidulated  water  and  ferric  chloride.  Other  methods  have 
been  suggested  by  Gscheidlen  and  Solera.  The  quantitative  estimation 
can  be  done  according  to  Munk's  ^  method. 

Ptyalin,  or  salivary  diastase,  is  the  amylolytic  enzyme  of  the  saliva. 
This  enzyme  is  found  in  human  saliva,*  but  not  in  that  of  all  animals, 
especially  not  in  the  typical  cirnivora.  It  occurs  not  only  in  adults,  but 
also  in  new-born  infants.  Zweifel  '  claims  that  the  ptyalin  in  new-born 
infants  occurs  only  in  the  parotid  gland,  but  not  in  the  submaxillary. 
In  the  latter  it  appears  only  two  months  after  birth. 

'  Chittenden  and  Ely,  Amer.  Cbem.  Jonrn.,  Vol.  4,  1883  ;  Chilteudeu  and  Richards, 
Anier.  .Journ.  of  Physiol.,  Vol.  1  ;  Strieker,  cited  from  Ceutralbl.  f.  Physiol.,  Bd.  3,  8. 
237. 

»  Zcitschr.  f.  Klin.  Med.,  Bd.  33. 

*  Gscheidlen,  Muly's  Jahresber.,  Bd.  4;  Solera,  see  ibid.,  Bdd.  7  and  8;  Munk,  Vir- 
chow's  Arch.,  Bd.  69. 

*  In  regard  to  the  variation  in  the  quantity  of  ptyalin  in  human  saliva  see  :  Hofbauer, 
Centralbl.  f.  Physiol.,  Bd.  10,  and  Chittenden  and  Richards,  Amer.  Journ.  of  Physiol., 
Vol.  1. 

*  Untersuchungen  ilber  den  Verdauungsapparal  der  Neugeborenen.     Berlin,  1874. 


PTTALIN.  263 

According  to  11.  Goldsciimidt  '  the  saliva  (parotid  saliva)  of  the  horse  does  not  con- 
tain ptyaliii,  iMii  a  zyniogea  of  the  sanu',  while  in  other  animals  and  man  the  pyialin  is 
foiuieil  from  the  y.ymogeu  during  secretion.  In  horses  the  zymogen  is  trausforiiied  into 
ptyalin  during  masticiition,  and  hacieria  seem  to  give  the  imi)ulse  to  this  change. 
During  precipitjflion  w  itli  alcohol  the  zymogen  is  changed  into  ptyalin. 

Ptyalin  lias  not  been  isolated  in  a  pnre  form  up  to  the  present  time.  It 
can  be  obtained  purest  by  CoiixnKi.M's''  method,  which  consists  in  carrying 
tiie  enzyme  down  mechanically  with  a  calcium-phosphate  precii:)itate  and 
washing  the  precipitate  with  water,  which  dissolves  the  ptyalin,  and  from 
which  it  can  be  obtained  by  precipitating  with  alcohol.  For  the  study  or 
demonstration  of  the  action  of  ptyalin  we  may  use  a  watery  or  glycerin 
extract  of  the  salivary  glands,  or  simply  the  saliva  itself. 

Ptyalin,  like  other  enzymes,  is  characterized  by  its  action.  This  consists 
in  converting  starch  into  dextrins  and  sugar.  In  regard  to  the  process 
going  on  in  this  conversion  we  are  not  quite  clear.  In  general  it  may  be 
described  as  follows:  In  the  first  stages  soluble  starch  or  amiduUn  is  formed. 
From  this  amidulin,  erythrodextrin  and  sugar  are  produced  by  hydrolytic 
cleavage.  The  erythrodextrin  then  splits  into  a-achroodextrin  and  sugar. 
From  this  achroodextrin  by  splitting  /?-achroodextrin  and  sugar  are  formed, 
and  finally  this  /5-achroodextrin  splits  into  sugar  and  ^-achroodextrin. 
According  to  a  few  investigators  the  niimber  of  dextrins  formed  as  inter- 
mediate steps  is  different.'  It  is  only  within  a  very  short  time  that  it  has 
been  made  clear  what  kind  of  sugar  is  produced  in  this  process.  For  a 
lonjj  time  it  was  considered  that  dextrose  was  the  sugar  formed  from  starch 
and  glycogen,  but  Seegen  and  0.  Nasse  have  shown  that  this  is  not  true. 

MuscuLUS  and  v.  Merixg  have  shown  that  the  sugar  formed  by  the 
action  of  saliva,  amylopsin,  and  diastase  upon  starch  and  glycogen  is  in 
greatest  part  maltose.  This  lias  been  substantiated  by  Browx  and  Heron. 
Lately  E.  KiJLZ  and  J.  Vogel*  have  demonstrated  that  in  the  saccharifica- 
tion  of  starch  and  glycogen  isomaltose,  maltose,  and  some  dextrose  are 
formed,  the  varying  quantities  depending  upon  the  amount  of  ferment  and 
length  of  action.  The  formation  of  glucose  is  claimed  by  Tebb,  Eoiimaxn 
and  IIamhurger^  to  be  only  a  product  of  the  inversion  of  the  maltose  by 
the  glucase. 

In  the  past  ptyalin  and  malt  diastase  were  not  considered  identical  on 


'  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 
5  Virchow's  Arch.,  Bd.  28. 
J  See  Chapter  III.  p.  89. 

*  Seegen,  Ceutralbl.  f.  d.  med.  "Wisseusch.,  1876,  and  Pfliiger's  Arch.,  Bd.  19  ;  Nasse, 
ibid.,  Bd.  14;  Mnscidus  and  v.  Mering,  Zeitschr.  f.  physiol.  Chem.,  Bd.  2  ;  Browa  and 
Heron,  Liebig's  Aunal.,  Bdd.  199  and  204;  Kulz  and  Vogel,  Zeitschr.  f.  Biologic,  Bd. 
31. 

*  Tebb.  Journ.  of  Physiol..  Vol.  15;  Rohmanu,  Ber.  d.  deutsch.  chem.  Gesellsch., 
Bd.  27  ;  Ilamburger,  Ptluger's  Arch.,  Bd.  60. 


254  DIGESTION. 

account  of  the  different  temperatures  at  which  they  are  most  active.  The 
correctness  of  such  a  view  has  been  disputed  by  the  researches  of  Puglise.  ' 

The  action  of  ptyalin  in  various  reactions  has  been  the  subject  of 
numerous  investigations."  Naturally  the  alkaline  saliva  is  very  active,  but 
it  is  not  as  active  as  when  neutral.  It  may  be  still  more  active  under  cir- 
cumstances in  faintly  acid  reaction,  and  according  to  Chittenden  and 
Smith  it  acts  better  when  enough  hydrochloric  acid  is  added  to  saturate 
the  proteids  present  than  when  only  simply  neutralized.  When  the  acid- 
combined  proteid  exceeds  a  certain  amount,  then  the  diastatic  action  is 
diminished.  The  addition  of  alkali  to  the  saliva  decreases  its  diastatic 
action;  on  neutralizing  the  alkali  with  acid  or  carbon  dioxide  the  retarding 
or  jDreventive  action  of  the  alkali  is  arrested.  According  to  Schierbeck 
carbon  dioxide  has  an  accelerating  action  in  neutral  liquids,  while  Ebstein 
claims  that  it  has  as  a  rule  a  retarding  action.  Organic  as  well  as  inorganic 
acids,  when  added  in  sufficient  quantity,  may  stop  the  diastatic  action 
entirely.  The  degree  of  acidity  necessary  in  this  case  is  not  always  the 
same  for  a  certain  acid,  but  is  dependent  upon  the  quantity  of  ferment. 
The  sam4  degree  of  acidity  in  the  presence  of  large  amounts  of  ferment  has 
a  weaker  action  than  in  the  presence  of  smaller  quantities.  Hydrochloric 
acid  is  of  special  physiological  interest  in  this  regard,  namely,  it  prevents 
the  formation  of  sugar  even  in  very  small  amounts  (0.03  p.  m.).  Hydro- 
chloric acid  has  not  only  the  property  of  preventing  the  formation  of  sugar, 
but,  as  shown  by  Langley,  Nylen",  and  others,  may  entirely  destroy  the 
enzyme.  This  is  important  in  regard  to  the  physiological  significance  of 
the  saliva.  That  boiled  starch  (paste)  is  quickly,  and  unboiled  starch  only 
slowly,  converted  into  sugar  is  also  of  interest.  Various  kinds  of  unboiled 
starch  are  converted  with  dilfferent  degrees  of  rapidity. 

The  rapidity  with  which  ptyalin  acts  increases,  at  least  under  conditions 
otherwise  favorable,  with  the  amount  of  enzyme  and  with  an  increasing 
temperature  to  a  little  above  +  40°  C.  Foreign  substances^  such  as  metallic 
salts,'  have  different  effects.  Certain  sr.lts  even  in  small  quantities  com- 
pletely arrest  the  action;  for  example,  HgCl,  accomplishes  this  result  com- 
pletely by  the  presence  of  only  0.05  p.  m.  Other  salts,  such  as  magnesium 
sulphate,  in  small  quantities  (0.25  p.  m.)  accelerate,  and  in  larger  quantities 

'  Pflilger's  Arch.,  Btl.  69. 

*  See  Hammarsten,  Miily's.Jahiesbcr.,  Bd.  1  ;  Chittenden  andGriswold,  Amer.  Chem. 
Journ,,  Vol.  3  ;  Langley,  Journal  of  Physiol.,  Vol.  3 ;  Nyleu,  Maly's  Jahresber.,  Bd.  12, 
8.  241  ;  Chittenden  and  Ely,  Amer.  Chcin.  Journ.,  Vol.  4;  Liuigley  and  Eves,  Journiil 
of  Pliysiol.,  Vol.  4;  Chittenden  and  Smith,  Yale  College  Studies,  Vol.  1,  1885,  p.  1  ; 
Scblesinger,  Virchow's  Arch.,  Bd.  125;  Shierheck,  Skand.  Arch.  f.  Physiol.,  Bd.  3; 
Ebstein  and  C.  Schulze,  Virchow's  Arch.,  Bd.  134. 

*  See  O.  Nasse,  Pfluger's  Arch.,  Bd.  11,  and  Chittenden  and  Painter,  Yale  College 
Studies,  Vol.  1,  1885.  p.  53. 


COMPOSITION  OF  SALIVA. 


265 


(5  p.  m.)  check  the  jiction.  Tlie  presence  of  peptone  has  an  accelerating 
action  on  the  sugar  formation  (Chittexdkn  and  Smith  and  others).  The 
accumulation  of,the  jjroducts  of  the  atnylohjtic  decomposition  also  checks  the 
action  of  the  saliva.  This  has  been  shown  by  special  experiments  made  by 
Su.  Lea,'  lie  made  parallel  experiments  with  digestions  in  test-tubes  and 
in  dialyzers,  and  found  on  the  removal  of  the  products  of  the  amylolytic 
decomposition  by  dialysis  that  the  formation  of  sugar  took  place  sooner, 
bat  also  that  considerably  more  maltose  and  less  dextrin  was  formed. 

To  show  the  action  o!  saliva  or  ptyalin  on  starch  the  three  ordinary  tests 
for  dextrose  may  be  used,  namely,  Moore's  or  Trommer's  test  or  the 
bismuth  test  (see  Chapter  XV).  It  is  also  necessary,  as  a  control,  to  first 
test  the  starch-pi'.ste  and  the  saliva  for  the  presence  of  dextrose.  The  steps 
formed  in  the  transformation  of  starch  into  amidulin,  erythrodextrin,  and 
achroodextrin  may  be  shown  by  testing  with  iodine. 

Glucase  only  occurs  in  saliva  to  a  slight  extent.  It  converts  maltose 
into  glucose.  According  to  Stricker  '  saliva  also  has  the  power  of  splitting 
sulphuretted  hydrogen  from  the  sulphur  oils  of  radishes,  onions,  and  certain 
other  kitchen  vegetables. 

The  quantitative  composition  of  the  mixed  saliva  must  vary  considerably, 
not  only  because  of  individual  differences,  but  also  because  under  varying 
conditions  there  may  be  an  unequal  division  of  the  secretion  from  the  differ- 
ent glands.  We  give  below  a  few  analyses  of  human  saliva  as  example  of 
its  composition.     The  results  are  in  parts  per  1000. 


Water 

Solids 

Mucus  and  epithelium    

Soluble  orgauic  substances  . 

(Ptyalin  of  early  investigators.) 

Sulpbocyanides 

Salts 


c 

1 

CO 

O 

m 

s 

S  d  " 

Id 

es 

a 

1 

S     a 

H 

K 

n 

o 

X 

a 

•-i 

992.9 

995.16 

994.1 

988.3 

994.7 

7.1 

4.84 

5.9 

11.7 

5.3 

3.5-8.4 

in 
filtered 
saliva. 

1.4 

1.62 

2.13 

3.8 

1.34 

1.42 

3.27 

0.06 

0.10 

0.064 

to 
0.09 

1.9 

1.82 

2.19 

1.03 

So 


994.2 
5.8 


2.2 
1.4 

0.04 


2.2 


Hammekbacheu  found  in  1000  parts  of  tbe  ash  from  human  saliva  :  potash  457.2, 
soda  95.9.  iron  oxide  50.11,  mairnesia  1.55,  sulphuric  anhydride  (SOj)  63.8,  phosphoric 
anhydride  (PjOj)  1S8.48,  and  chlorine  183.52. 


■  Journ.  of  Physiol.,  Vol.  11. 
'  Miinch.  uicd.  TVochenschr. ,  Bd.  43. 

3  Zeitschr.   f.  physiol.  Chem.,  Bd.   5.      The  other  analyses  are  cited  from  Maly. 
Chemie  der  Verdauunsssafte,  Hermann's  Haudbuch  d.  Physiol.,  Bd.  5,  Th,  2,  8.  14. 


256  DIGESTION. 

The  quantity  of  saliva  secreted  during  24  hours  cannot  be  exactly  deter- 
mined, but  has  been  calculated  by  Biddee  and  Schmidt  to  be  1400-1500 
grms.  The  most  abundant  secretion  occurs  during  meal-times.  According 
to  the  calculations  and  determinations  of  Tuczek  '  in  man,  1  grm.  of  gland 
yields  13  grms.  secretion  in  the  course  of  one  hour  during  mastication. 
These  figures  correspond  fairly  well  with  those  representing  the  average 
secretion  from  1  grm.  of  gland  in  animals,  namely,  14.2  grms.  in  the  horse 
and  8  grms.  in  oxen.  Tlie  quantity  of  secretion  per  hour  may  be  8  to  14 
times  greater  than  the  entire  mass  of  glands,  and  there  is  probably  no  gland 
in  the  entire  body,  as  far  as  we  know  at  present — the  kidneys  not  excepted 
— whose  ability  of  secretion  under  physiological  conditions  equals  that  of 
the  salivary  glands.  A  remarkably  abundant  secretion  of  saliva  is  induced 
by  pilocarpin,  while  atropin,  on  the  contrary,  prevents  it. 

Though  an  abundant  secretion  of  saliva  is  produced,  as  a  rule,  by  an 
increased  snpj)ly  of  blood,  still  it  is  not  a  simple  filtration  process,  as  seen 
from  the  following  circumstances.  The  secretion-pressure  is  greater  than 
the  blood-pressure  in  the  carotid,  and  in  poisoning  by  atropin,  which 
paralyzes  the  secretory  nerves,  an  increased  supply  of  blood  is  produced  by 
irritation  of  the  chorda,  but  no  secretion.  The  salivary  glands  have  more- 
over a  specific  property  of  eliminating  certain  substances,  such  as  potassium 
salts  (Salkowski*),  iodine,  and  bromine  combinations,  but  not  others,  such 
as  iron  combinations.  It  is  also  noticeable  that  the  saliva  is  richer  in  solids 
when  it  is  eliminated  quickly  by  gradually  increased  irritation,  and  in  larger 
quantities  than  when  the  secretion  is  slower  and  less  abundant  (Heidex- 
HAix).  The  amount  of  salts  increases  also  to  a  certain  degree  by  an 
increasing  rapidity  of  elimination  (Heidekhahs",  Weether,  Langley  and 
Fletcher,  Xovi'). 

Like  the  secretion  processes  in  general,  the  secretion  of  saliva  is  closely 
connected  with  tlie  processes  in  the  cells.  The  chemical  processes  going  on 
in  these  cells  during  secretion  are  still  unknown. 

The  Physiological  Tm^iortance  of  the  Saliva.  The  quantity  of  water  in 
the  saliva  renders  possible  the  effects  of  certain  bodies  on  the  organs  of  taste, 
and  it  also  serves  as  a  solvent  for  a  part  of  the  nutritive  substances.  The 
importance  of  the  saliva  in  mastication  is  especially  marked  in  herbivora, 
and  there  is  no  question  of  its  importance  in  facilitating  the  act  of  swallow- 
ing. The  power  of  converting  starch  into  sugar  is  not  inherent  in  the 
saliva  of  all  animals,  and  even  when  it  possesses  this  i:)roperty  the  intensity 


»  Bidder  and  Schmidt,  1.  c,  S.  13 ;  Tuczek.  Zeitschr.  f.  Biologic,  Bd.  12. 

*  Virchow's  Arch.,  Bd.  53. 

»  Heidenliain,  Pfiuger's  Arch.,  Bd.  17  ;  Werther,  ihid.,  Bd.  38  ;  Langle3^and  Fletcher, 
Proc.  Hoy.  Soc,  Vol.  45,  and  especially  Phil.  Trans.  Roy.  Soc.  London,  Vol.  180  ;  Novi, 
Du  Bois-Reymond's  Arch.,  1888. 


GIANDS  OF  THE  STOMACIJIC  MUCOSA.  257 

Taries  in  different  animals.  In  man,  whose  saliva  forms  sngar  rapidly,  a 
formation  of  sugar  from  (boiled)  starch  undoubtedly  takes  place  in  the 
mouth,  but  how  far  this  action  goes  on  after  the  morsel  has  entered  the 
stomach  dependB  upon  the  rapidity  with  which  the  acid  gastric  juice  mixes 
with  the  swallowed  food,  and  also  upon  the  relative  amounts  of  the  gastric 
juice  and  food  in  the  stomach.  The  large  quantity  of  water  which  is 
swallowed  with  the  saliva  must  be  absorbed  and  i)ass  into  the  blood,  and  it 
must  go  through  an  intermediate  circulation  in  the  organism.  Thus  the 
organism  possesses  in  the  saliva  an  active  medium  by  which  a  constant 
stream,  conveying  the  dissolved  and  finely  divided  bodies,  passes  into  the 
blood  from  the  intestinal  canal  during  digestion. 

Salivary  Concrements.  The  so-culled  tartar  is  yellow,  gray,  yellowish  gray,  brown  or 
black,  and  has  a  stratitied  structure.  It  may  contaiu  more  liiiin  200  p.  m.  cr^^anic  sub- 
stances, which  consist  of  mucin,  epithelium,  and  leptothrix-chains.  The  chief  part 
of  the  inorganic  cousiituents  consists  of  calcium  carbonate  and  phosphate.  The  salivary 
calculi  may  vary  in  size  from  that  of  a  small  grain  to  that  of  a  pea  or  still  hirgfr  (a  sali- 
vary calculus  has  been  found  weighing  18.6  grms.),  and  it  contains  a  variable  quantity  of 
organic  substances  (50-380  p.  m),  which  remain  on  extracting  the  calculus  with  hydro- 
chloric acid.     The  chief  inorganic  constituent  is  calcium  carbonate. 

II.  The  Glands  of  the  Mucous  3Ienibrane  of  the 
Stomach,  and  the  Gastric  Juice. 

Since  of  old,  the  glands  of  the  mucous  coat  of  the  stomach  have  been 
■divided  into  two  distinct  kinds.  Those  which  occur  in  the  greatest  abun- 
dance and  which  have  tiie  greatest  size  in  the  fundus  are  called  fundus 
glands,  also  rennin  or  pepsin  glands.  Those  which  occur  only  in  the  neigh- 
borhood of  the  pylorus  have  received  the  name  of  pyloric  glands,  sometimes 
also,  though  incorrectly,  called  mucous  glands.  The  mucous  coating  of  the 
stomach  is  covered  throughout  with  a  layer  of  columnar  epithelium,  which 
is  generally  considered  as  consisting  of  goblet  cells  that  produce  mucus  by  a 
metamorphosis  of  the  protoplasm. 

The  fundus  glands  contain  two  kinds  of  cells:  adelomorphic  or  chief 
cells,  and  delomorphic  or  parietal  cells,  the  latter  formerly  called 
R^xxix  or  pepsin  cells.  Both  kinds  consist  of  protoplasm  rich  in  proteids; 
but  their  relationship  to  coloring  matters  seems  to  show  that  the  albuminous 
bodies  of  both  are  not  identical.  The  nucleus  must  consist  chiefly  of 
nuclein.  Besides  the  above-mentioned  constituents  the  fundus  glands 
contain  as  more  specific  constituents  two  zyinogens,  which  are  the  mother- 
substances  of  t\\e  pepsin  and  the  rennin,  besides  a  small  quantity  of  fat  and 
cholesteriu. 

The  pyloric  glands  contain  cells  which  are  generally  considered  as 
related  to  the  above-mentioned  chief  cells  of  the  fundus  glands.  As  these 
glands  were  formerly  thought  to  contain  a  larger  quantity  of  mucin,  they 
were  also  called  mucous  glands.     According  to  Heidenhaix,  independent 


258  DIGESTION. 

of  the  columnar  epithelinm  of  the  excretory  ducts  they  take  no  part  worthj 
of  mention  in  the  formation  of  mucus,  which,  according  to  his  views,  is 
effected  by  the  epithelium  covering  the  mucous  membrane.  The  pyloric 
glands  also  seem  to  contain  the  zymogens  referred  to  above.  Alkali  chlo- 
rides, alkali  phosphates,  and  calcium  phosphates  are  found  in  the  mucous 
coating  of  the  stomach. 

LiEBERMANN  ^  hus  Obtained  an  acid-reacting  residue  on  digesting  the  mucosa  of  the 
slomacli  v/iih  pepsin  hydrochloric  acid,  which  strangely  contained  no  nuclein,  but  only 
a  proteid  containing  lecithin,  called  lecithalbuniin.  To  this  lecitbalbumin  he  ascribes  a 
great  imporlauce  in  the  secretion  of  hydrochloric  acid  (see  below). 

The  Gastric  Juice.  The  observations  of  Helm  and  Beaumont  on 
persons  with  gastric  fistula  led  to  the  suggestion  that  gastric  fistulas  be 
made  on  animals,  and  this  operation  was  first  performed  by  Bassow  '^  in 
1842  on  a  dog.  Verneuil  performed  the  same  on  a  man  in  187G  with 
successful  results.  Pawlow  °  has  recently  improved  the  surgery  of  gastric 
fistula  and  has  added  much  to  the  study  of  the  gastric  secretion. 

The  secretion  of  gastric  juice  is  not  continuous,  at  least  in  man  and  the 
mammals  experimented  upon.  It  only  occurs  under  psychic  influence,  and 
also  by  j/rritation  of  the  mucous  membrane.  According  to  the  ordinary  view 
this  irntation  may  be  of  a  mechanical,  thermic,  or  chemical  nature.  Among 
the  latter  we  include  alcohol  and  ether,  which  when  in  too  great  concentra- 
tion do  not  produce  a  physiological  secretion,  but  a  transudatiou  of  a 
neutral  or  faintly  alkaline  fluid.  To  this  class  certain  acids,  carbon  dioxide, 
neutral  salts,  meat  extracts,  spices,  and  other  bodies  also  belong,  but  unfor- 
tunately the  reported  observations  are  uncertain  and  contradictory. 

The  most  exhaustive  researches  on  the  secretion  of  gastric  juice  (in  dogs) 

has  been  done  by  Pawlow  and  his  pupils.* 

In  order  to  obtain  gastric  juice  free  from  saliva  and  food  residues  they  arranged 
besides  a  gastric  listula  also  an  oesophagus  fistula  from  which  the  swallowed  food  could 
be  withdrawn  with  tlie  saliva  without  entering  the  stomach,  and  in  this  an  apparent  feed- 
ing was  possible.  In  this  way  it  was  possiljle  to  study  the  influence  of  i^sychical 
moments  on  one  side  and  the  direct  action  of  food  on  the  mucous  membrane  on  the 
other.  After  a  method  suggested  by  Heidenhain  and  later  improved  by  Pawlow  and 
Khigine,  tliey  have  succeeded  in  preparing  a  blind  sac  by  partial  dissection  of  the  fundus 
part  of  the  stomach,  and  the  secretion  processes  could  be  studied  in  this  sac  while  the 
digestion  in  the  other  parts  of  the  stomach  was  going  on.  In  this  way  they  were  able  to 
study  the  action  of  dill'erent  foods  on  the  secretion. 

The  most  essential  results  of  the  investigations  of  Pawlow  and  his 
pupils  are  as  follows:  ]\[echanical  irritation  of  the  mucosa  does  not  produce 

'  PfiQger's  Arch.,  Bd.  50. 

'  Helm,  Zwei  Krankengeschichten.  Wien,  1803.  Cit.  from  Hermann's  Handbucb, 
Bd.  5,  Th.  2,  S.  39.  Beaumont,  "The  Physiology  of  Digestion,"  1833  ;  Bassow,  Bull, 
de  la  soc.  des  natur.  de  Moscou,  Tome  16.  Cit.  from  Maly  in  Hermann's  Handbuch, 
Bd.  5,  S.  38  ;  Vcrucuil,  see  C'h.  llichet,  "Du  Sac  gastrique  chez  I'homme,"  etc.  (Paris, 
1878),  p.  158. 

'  Pawlow,  Die  Arbeit  der  Verdauungsdrusen  (Wiesbaden,  1898),  where  the  works  of 
his  pupils  are  also  mentioned. 

*L.  0. 


GASTRIC  JUICE.  25^ 

any  secretion.  Chemical  and  mechanical  irritations  of  the  mucous  mem- 
brane of  the  mouth  cause  no  reflex  excitation  of  the  secretory  nerves  of  the 
stomach.  There  are  only  two  moments  which  cause  a  secretion,  namely, 
the  psychical  moment — the  passionate  desire  for  food  and  the  sensation  of 
satisfaction  and  pleasure  on  partaking  it — and  the  chemical  moment,  the 
action  of  certain  chemical  substances  on  the  mucous  membrane  of  the 
stomach.  The  first  moment  is  the  most  important.  The  secretion  occur- 
ring under  its  influence  by  the  vagus  fibres  appears  earlier  than  that 
produced  by  chemical  irritants,  but  always  after  a  pause  of  at  least  A:\ 
minutes.  Tliis  secretion  is  more  abundant  but  less  continuous  than  the 
"chemical."  It  yields  a  more  acid  and  active  juice  than  the  latter.  As 
chemical  irritants,  which  cause  a  secretion  reflexively  through  the  stomach 
mucosa,  we  include  only  water  and  certain  unknown  extractive  substances 
contained  in  meat  and  meat  extracts,  in  impure  peptone,  and  also,  it  seems, 
in  milk.  Carbonated  alkalies  have  a  preventive  instead  of  an  acceleratinor 
action  on  secretion.  Fats  have  a  retarding  action  on  the  appearance  of 
secretion,  and  diminish  the  quantity  of  juice  secreted  as  well  as  the  amount 
of  enzyme.  The  substances,  such  as  egg-albumin,  which  act  as  chemical 
irritants  cannot  be  digested  by  the  "  psychical  "  secretion,  but  may  perhaps 
cause  a  chemical  secretion  by  their  decomposition  products. 

The  quantity  of  juice  secreted  during  digestion  is  proportional  to  the 
quantity  of  food,  and  the  secretion  of  gastric  juice  may  also  be  influenced  by 
the  kind  of  food.  This  action  of  various  foods,  meat,  bread,  and  milk  may 
be  arranged  in  progressive  series  as  follows: 


Aciditr. 

Digestive  Activity. 

Duration  of  Secretion. 

1.     Meat. 

Bread. 

Bread. 

2.     Milk. 

Meat. 

Meat. 

3.     Bread. 

Milk. 

Milk. 

The  acidity  is  greatest  with  a  meat  diet  and  lowest  with  bread;  the 
quantity  of  enzyme  is,  on  the  contrary,  highest  with  a  bread  diet  and 
lowest  with  milk. 

We  know  hardly  anything  positively  in  regard  to  the  condition  in  man, 
and  the  reports  at  hand  are  very  contradictory.  There  is  hardly  any  doubt 
that  in  man  also  various  foods  have  an  influence  on  the  secretion  in  different 
ways,  and  it  seems  as  if  the  extractive  substances  of  meat  are  the  most 
powerful  of  the  chemical  irritants  (Verhaegen  '). 

Tlie  Qualitative  and  Quantitative  Comjmsition  of  the  Gastric  Jvice, 
The  gastric  juice,  Avhich  can  hardly  be  obtained  pure  and  free  from  residues 
of  the  food  or  from  mucus  and  saliva,  is  a  clear,  or  only  very  faintly  cloudy, 
and  in  man  nearly  colorless  fluid  of  an  insipid,  acid  taste  and  strong  acid 
reaction.  It  contains,  as  form-elements,  (jlandidar  cells  or  their  )iuciei, 
unums-corpuscles,  and  more  or  less  changed  cohimnar  epithelitim. 
'  See  the  works  of  Verbaegen  in  "La  Cellule,"  1896  aud  1897. 


260  DIGESTION. 

The  acid  reaction  of  the  gastric  juice  depends  on  the  presence  of  free 
acid,  which,  as  we  have  learned  from  the  investigations  of  C.  Schmidt, 
KiCHET  and  others,  consists,  when  the  gastric  juice  is  pure  and  free  from 
particles  of  food,  chiefly  or  in  large  part  of  hydrochloric  acid.  Contejean  * 
has  regularly  found  traces  of  lactic  acid  in  the  pure  gastric  juice  of  fasting 
dogs.  After  partaking  of  food,  especially  after  a  meal  rich  in  carbo- 
hydrates, lactic  acid  occurs  abundantly,  and  sometimes  acetic  and  butyric 
acids.  The  quantity  of  free  hydrochloric  acid  in  the  gastric  juice  of 
dogs,  is  commonly  considered  to  be  about  2-3  p.  m. ,  but  tliese  figures 
are  not  based  on  pure  gastric  juice,  as  Pawlow  and  his  pupils  have  shown 
that  the  gastric  juice  of  the  dog  contains  5-6  p.  m.  and  that  of  the  cat  an 
average  of  5.20  p.  m.  HCl  (Riasantzen*).  In  man  the  acidity  has  been 
found  to  vary  considerably,  but  it  is  generally  calculated  as  2-3  p.  m.  HCl. 
According  to  Yerhaegen's  researches  there  is  no  doubt  that  pure  human 
gastric  juice  from  perfectly  healthy  persons  has  a  higher  acidity.  There  is 
hardly  any  doubt  that  at  least  a  part  of  the  hydrochloric  acid  of  the  gastric 
juice  does  not  exist  free  in  the  ordinary  sense,  but  combined  with  organic 
substances.^ 

Perfectly  fresh  gastric  juice  seems  to  contain  a  little  coagulable  nucleo>- 
proteid,  but  contains  albunioses  on  standing  for  some  time.     Among  the 
organic  bodies  are  found  a  little  iiwcin  and  two  enzymes,  jje;;6m  and  rennin^ 
especially  in  man. 

The  specific  gravity  of  gastric  juice  is  low,  1.001-1.010.  It  is  corre- 
spondingly poor  in  solids.  Older  analyses  of  gastric  juice  from  man,  the  dog, 
and  the  sheep  have  been  made  by  C.  Schmidt.^  As  these  analyses  refer  only 
to  impure  gastric  juice  they  are  of  little  value.  The  quantity  of  solids  in 
saliva-free  gastric  juice  from  a  dog  was  27  p.  m.,  with  17.1  p.  m.  organic 
substance.  The  quantity  of  free  hydrochloric  acid  was  3.1  p.  m.  Besides 
these  Schmidt  found  XaCl  1.46;  CaCl,  0.6;  KCl  1.1;  NH^Cl  0.5;  earthy 
phosphates  1.9;  and  FePO^  0.1  p.  m,  Nencki^  found  5  milligrams 
snlphocyanic  acid  per  liter  of  gastric  juice  of  a  dog. 

Besides  the  free  hydrochloric  acid  pepsi?i  and  rennin  are  the  other 
physiologically  important  constituents  of  gastric  juice. 

Pepsin.  This  enzyme  is  found,  with  the  exception  of  certain  fishes,  in 
all  vertebrates  thus  far  investigated. 

Pepsin  occurs  in  adults  and  in  new-born  infants.     This    condition  is 

•Bidder  and  Schmidt,  Die  Venlauung.silfle.  etc.,  S.  44;  Richet,  I.e.;  Contejcau, 
Conlribulions  ^  I'etude  de  la  pbysiol.  de  I'estomac.  Theses.     Paris,  1892. 

*  Arcb.  des  Scienc.  biol.  de  St.  Petersbourg,  Tome  3. 

'  See  Ricbet,  1.  c;  Contejean,  1.  c. ;  Verbaegen,  1.  c. ;  and  tbe  literature  on  tbe  estima- 
tion  of  hydrochloric  acid  in  the  gastric  contents  (see  page  278). 
*L.  c. 

*  Ber.  d.  deutsch.  chem.  Gcsellsch.,  Bd.  28. 


PEPSIN.  26 1 

(lifTerent  in  new-born  animals.  While  in  a  few  lierbivora,  siicli  as  the 
rabbit,  pepsin  occurs  iu  the  mucous  coat  before  birth,  this  enzyme  is 
entirely  absent  at  the  birth  of  those  carnivora  which  have  thus  far  been 
examined,  such  as  the  dog  and  cat. 

Ill  various  invertebrates  a  ferment  has  also  been  found  wliicli  has  :i  proteolytic  action 
in  add  soluti  >ns.  It  has  been  shown  tliat  this  enzyme,  nevertheless,  is  not  in  all  animals 
identical  with  ordinary  pepsin.  According  to  Klug  and  Wkoblewski  '  the  pepsins 
found  in  man  and  various  hit^her  animals  are  somewhat  different.  Dakwin  and  others 
have  further  founii  that  certain  plants  which  feed  upon  insects  secrete  an  acid  juice  which 
dissolvi's  proteid,  but  it  is  still  doubtful  whether  these  plants  contain  any  pepsin,  v, 
Gohtp-Besanez  has  isolated  from  vetch-seed  an  enzyme  which  acts  like  pepsin,  but  its 
identity  with  pepsin  doubtful.  Neumeistek  has  found  the  same  in  acrospire,  and  IIjort  • 
in  a  fungus,  polyporus  sulphurens. 

Pepsin  is  as  difficult  to  isolate  in  a  pure  condition  as  other  enzymes. 
The  pepsin  prepared  by  Brucke  and  Sundberg  gave  negative  results  with 
most  reagents  for  proteids,  and  showed  nevertheless  a  powerful  action  which 
seems  to  show  that  it  is  very  ])ure.  ScnouMOw-SiMAXOwsKi  and  Pekel- 
]IARIXG  '  have  designated  as  a  true  enzyme  a  nucleoproteid  which  coagulates 
on  boiling  and  is  soluble  in  water  and  which  separates,  on  cooling  perfectly 
fresh  dog  gastric  juice  and  is  active  even  on  very  strong  dilution.  Further 
investigations  on  this  substance  are  very  desirable.  It  is,  at  least  in  the 
impure  condition,  soluble  in  water  and  glycerin.  It  is  precipitated  by 
alcohol,  but  only  slowly  destroyed.  It  is  quickly  destroyed  by  heating  its 
watery  solution  to  boiling.  According  to  Biernacki*  pepsin  in  neutral 
solutions  is  destroyed  by  heating  to  +  55°  C.  In  the  presence  of  2  p.  m. 
IICl  a  temperature  of  bb''  C.  is  without  action;  the  pepsin  in  acid  solution 
is  destroyed  by  heating  to  65°  C.  for  five  minutes.  On  adding  peptone  and 
certain  salts  the  pepsin  may  be  heated  to  70°  C.  without  decomposing.  In 
the  dry  state  it  can,  on  the  contrary,  be  heated  to  over  100°  C.  without 
losing  its  physiological  action.  The  only  property  which  is  characteristic 
of  pepsin  is  that  it  dissolves  proteid  bodies  in  acid,  bat  not  in  neutral  or 
alkaline,  solutions  with  the  formation  of  albumoses  and  peptones. 

The  methods  for  the  preparation  of  relatively  pnre  pepsin  depend,  as  a 
rule,  upon  its  property  of  being  thrown  down  with  finely  divided  precipi- 
tates of  other  bodies,  sucli  as  Ciileium  phosphate  or  cholesterin.  The  ratiier 
complicated  methods  of  Brucke  and  Sundberg  are  based  upon  tliis 
property.  Pekeliiaring  makes  nseof  a  prolonged  dialysis  and  precipitation 
with  0.2  p.  m.  HCl.  A  relatively  pure  pepsin  solution  intended  for  diges- 
tion tests  and  of  effective  action  may  be  prepared  by  the  following  method 

'  Klug,  Pflliger's  Arch.,  Bd.  60;  Wroblewski.  Zeitschr.  f.  physiol.  Chem.,  lid.  21. 
'  V.  Gorup-Besancz,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  T  and  8;  Neumeister, 
Zeitschr.  f.  Biologic,  Bd.  30  ;  Hjort,  Centralbl.  f.  Physiol.,  Bd.  10. 

*  Brucke,  Wieu.  Sitzungsber.,  Bd.  43  :  Sundberg,  Zeitschr.  f.  physiol.  Chem.,  Bd.  9  ; 
Schoumow-Simanowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  33  ;  Pekelharing,  Zeitschr. 
f.  physiol.  Chem.,  Bd.  22. 

*  Zeitschr.  f.  Biologic,  Bd.  28. 


262  DIOESTION. 

as  suggested  by  Maly.  '  The  mucous  membrane  (of  the  pig's  stomach)  is 
treated  with  water  containing  phosphoric  acid,  and  the  filtrate  precipitated 
by  lime-water;  the  precipitate,  which  contains  the  pepsin,  is  then  dissolved 
in  water  by  the  addition  of  hydrochloric  acid,  and  the  salts  removed  by 
dialysis,  by  which  means  the  pepsin  which  does  not  diffuse  remains  in  the 
dialjzer.  A  pepsin  solution  somewhat  impure  but  rich  in  pepsin,  and  which 
can  be  kept  for  years,  may  be  obtained  if,  as  suggested  by  v.  Wittichs," 
we  extract  the  finely  divided  mucous  membrane  with  glycerin,  or  better 
with  glycerin  which  contains  1  p.  m.  HCl.  To  each  part  by  weight  of  the 
mucous  coat  add  10-20  parts  glycerin.  This  is  filtered  after  8-14  days. 
The  pepsin  (together  with  much  albumin)  may  be  precipitated  by  alcohol 
from  this  extract.  If  this  extract  is  to  be  used  directly  for  digestion  tests, 
then  to  100  c.c.  of  water  which  has  been  acidified  with  1-4  p.  m.  HCl  .add 
2-3  c.c.  of  the  extract. 

For  digestion  tests  an  infusion  of  the  mucous  membrane  of  the  stomach 
may  be  used  directly  in  many  cases.  The  mucous  coat  is  carefully  washed 
with  water  (if  a  pig's  stomach  is  nsed)  and  finely  cut;  if  a  calf's  stomach 
is  employed,  only  the  outer  layer  of  the  mucous  coat  is  scraped  off  with  a 
watch-glass  or  the  back  of  a  knife.  The  pieces  of  mucous  membrane  or  the 
slimy  masses  obtained  by  scraping  are  rubbed  with  pure  quartz-sand,  treated 
with  £(!cidified  water,  and  allowed  to  stand  for  24  hours  in  a  cool  place  and 
then  filtered. 

In  the  preparation  of  artificial  gastric  juice  that  part  only  of  the 
mucous  coat  richest  in  pepsin  is  used ;  the  pyloric  part  is  of  little  value. 
A  strong,  impure  infusion  may  generally  be  obtained  from  the  pig's 
stomach,  while  a  relatively  pure  and  powerful  infusion  is  obtained  from  the 
stomach  of  birds  (hens).  '  The  stomachs  of  fish  (pike)  also  yield  a  tolerably 
pure  and  active  infusion.  An  active  and  rather  pure  at'tificial  gastric  juice 
may  be  prepared  by  scraping  the  inner  layers  of  a  calf's  stomach  from  which 
the  pyloric  end  has  been  removed.  For  a  medium-sized  calf's  stomach 
1000  c.c.  of  acidified  water  must  be  used. 

The  degree  of  acidity  required  in  the  infusion  depends  upon  the  use  to 
which  the  gastric  juice  is  to  be  put.  If  it  is  to  be  employed  in  the  digestion 
of  fibrin,  an  acidity  of  1  p.  m.  HCl  must  be  selected,  while,  on  the  contrary, 
if  it  is  to  be  nsed  for  the  digestion  of  hard-boiled-egg  sdhumin,  an  acidity 
of  2-3  p.  m.  HCl  is  preferable.  This  last-mentioned  degree  of  acidity  is 
generally  the  better,  because  the  infusion  is  preserved  thereby,  and  at  all 
events  it  is  so  rich  in  pepsin  that  it  may  be  diluted  with  water  until  it  has 
an  acidity  of  1  p.  m.  IICI  without  losing  any  of  its  solvent  action  on 
unboiled  fibrin. 

The  preparation  of  acid  infusions  is  nowadays  unnecessary  on  account 
of  the  ability  of  getting  various  pepsin  preparations  in  commerce  which  have 
a  remarkable  activity.  Such  a  pepsin  preparation  can  be  purified  when 
necessary  by  following  the  method  suggested  by  Kuhne.'  Precipitate  the 
pepsin  together  with  the  alljtimoses  by  ammonium  sulphate,  press  the  pre- 
cipitate and  dissolve  in  dilute  hydrochloric  acid,  and  let  it  undergo  auto- 
digestion.  On  repeating  this  again  and  then  removing  the  salts  by  dialysis 
we  obtain  an  extraordinarily  active  pepsin,  but  which  is  still  less  pure  than 
when  obtained  by  tlie  methods  of  Bhucke  and  Sundberg. 

"  ilPlluger's  Arch.,  Bd.  9.  »  Ibid.,  Bd.  2. 

»  Zeitscbr.  f.  Biologic,  Bd.  23,  S.  428. 


ACTION  OF  PEPS  J  X  OA   PHOT  KIDS.  263 

Tlie  Action  q/'  J'cpsin  on  Proteids.  Pepsin  is  inactive  in  nentral  or 
alkaline  reactions,  but  in  acid  liquids  it  dissolves  coagulated  albuminous 
bodies.  The  proteid  always  swells  and  becomes  transparent  before  it  dis- 
solves. 'Jnboiled  fibrin  swells  up  in  a  solut'on  containing  1  p.  m.  HCl, 
forming  a  gelatinous  mass,  and  does  not  dissolve  at  ordinary  temperature 
within  a  couple  of  days.  Upon  the  addition  of  a  little  pepsin,  however, 
this  swollen  mass  dissolves  quickly  at  an  ordinary  temperature.  Ilard- 
boiled-egg  albumin,  cut  in  thin  jiieces  with  sharp  edges,  is  not  perceptibly 
changed  by  dilute  acid  (2-4  p.  m.  IICl)  at  the  temperature  of  the  body  in 
the  course  of  several  hours.  But  the  simultaneous  presence  of  pepsin 
causes  the  edges  to  become  clear  and  transparent,  blunt  and  swollen,  and 
the  albumin  gradually  dissolves. 

From  what  has  been  said  above  in  regard  to  pepsin,  it  follows  that 
proteids  may  be  employed  as  a  means  of  detecting  pepsin  in  liquids.  Fibrin 
may  be  employed  as  well  as  hard-boiled-egg  albumin,  which  latter  is  used  in 
the  form  of  slices  with  sharp  edges.  As  the  fibrin  is  easily  digested  at  the 
normal  temperature,  wliile  the  pepsin  test  with  egg-albumin  requires  the 
temperature  of  the  body,  and  as  the  test  with  fibrin  is  somewhat  more 
delicate,  it  is  often  preferred  to  that  with  egg-albumin.  When  we  speak  of 
the  ^^  2)epsin  test  "  without  further  explanation,  we  ordinarily  understand  it 
as  the  test  with  fibrin. 

This  test  nevertheless  requires  care.  The  fibrin  used  should  be  ox-fibrin 
and  not  pig-fibrin,  wiiich  last  is  dissolved  too  readily  with  dilute  acid  alone. 
The  unboiled  fibrin  may  be  dissolved  by  acid  alone  without  pepsin,  but  this 
generally  requires  more  time.  In  testing  with  unboiled  fibrin  at  normal 
temperature,  it  is  advisable  to  make  a  control  test  with  another  portion  of 
the  same  fibrin  with  acid  alone.  Since  at  the  temperature  of  the  body 
unboiled  fibrin  is  more  easily  dissolved  by  acid  alone,  it  is  best  always  to 
"work  with  boiled  fibrin. 

As  pepsin  has  not,  thus  far,  been  prepared  in  a  positively  pure  condition, 
it  is  impossible  to  determine  the  absolute  quantity  of  pepsin  in  a  liquid.  It 
is  only  possible  to  compare  the  relative  amounts  of  pepsin  in  two  or  more 
liquids,  which  may  be  done  in  several  ways.  As  the  best  of  these  we  give 
the  following  method  as  suggested  by  Brucke. 

If  two  pepsin  solutions  A  and  B  are  to  be  compared  with  each  other  relatively  to  the 
amounts  of  pepsin  they  contain,  they  must  first  be  brought  to  the  proper  degree  of  acidity, 
about  1  p.  m.  HCl,  care  being  taken  that  one  is  not  more  diluted  than  the  other.  Then 
prepare  a  l.nize  number  of  specimens  of  each  solution  by  diluting  with  liydrochloric  acid 
of  1  p.  m.  HCl,  so  that  they  contain  respectively  \,  \,  \,  ,V.  iv,  and  so  on,  the  amount  of 
pepsin  in  the  original  liquid  being  1.  If  the  original  quantity  "of  pepsin  in  the  two  liquids 
is  designated  by  p  and  p' ,  we  then  have  the  two  series  of  liquids  : 


A 

B 

\p 

\p' 

iP 

w 

iP 

ip' 

\P 

w 

^\P 

iVP' 

nhP 

isP' 

264  DIGESTION. 

Then  a  small  piece  of  boiled-egg  albumin,  obtained  by  cutting  thin  slices  with  a  cork- 
cutter,  is  placed  iu  each  test,  or  a  small  flake  of  fibrin  is  added.  Of  course  care  must  be 
taken  to  add  the  same-sized  slice  of  egg-albumin  or  flake  of  fibrin.  Now  observe  and  note 
exactly  the  time  when  each  test  of  the  two  series  begins  to  digest  and  when  it  ends,  and 
it  will  be  found  that  certain  tests  of  one  series  make  about  the  same  progress  as  certain 
tests  of  the  other  series.  It  may  be  inferred  from  this  that  they  contain  about  the 
same  quantity  of  pepsin.  As  example,  it  is  found  in  one  series  of  tests  that  the  digestive 
rapidity  of  the  tests  p\,  p  i^,  p  sV  is  about  the  same  as  the  tests  p'  ^,  p'  i,  p'  \;  therefore 
we  conclude  that  the  liquid  A  is  about  lour  times  as  rich  in  pepsin  as  the  liquid  B. 

Another  method  as  suggested  by  Mett  •  gives  more  exact  results  according  to  the 
investigations  of  Samojlopf.     Draw  up  liquid  white  of  egg  in  a  glass  tube  of  about  1  to 

2  ram.  diameter  and  coagulate  the  albumin  in  the  tube  by  heating,  cut  the  ends  of  the 
tube  off  sharply,  add  two  tubes  to  each  test-tube  with  a  few  cc.  of  acid  pepsin  solution, 
allow  to  digest  at  the  bodily  temperature,  and  after  a  certain  time  measure  the  lineal 
extent  of  the  digested  layer  of  albumin  in  the  various  tests.  The  quantity  of  pepsin  in 
the  comparative  tests  is  as  the  square  of  the  millimeters  of  albumin  columns  dissolved 
in  the  same  time.     Thus  if  in  one  case  2  mm.  of  albumin  was  dissolved  and  in  the  other 

3  mm.,  then  the  quantity  of  pepsin  is  as  4  :  9. 

The  rapidity  of  the  pepsin  digestion  depends  on  several  circamstances. 
Thus  dif event  acids  are  ttneqaal  in  their  action;  hydrochloric  acid  shows  in 
slight  concentration,  0.8-1.8  p.  m.,  a  more  powerful  action  than  any  other, 
whether  inorganic  or  organic.  In  greater  concentration  other  acids  may 
have  a  powerfal  action,  and  we  can  say  that,  as  a  rule,  the  acids  having  the 
greatest  avidity  have  a  greater  action  in  slight  concentration  than  weak 
acids.  Still  sulphuric  acid  forms  an  exception  (Pfleiderer).  The  state- 
ments in  regard  to  the  action  of  various  acids  are  somewhat  contradictory.^ 
The  degree  of  acidity  is  also  of  the  greatest  importance.  With  hydrochloria 
acid  the  degree  of  acidity  is  not  the  same  for  different  proteid  bodies.  For 
fibrin  it  is  0.8-1  p.  m.,  for  myosin,  casein,  and  vegetable  proteids  abont 
1  p.m.,  for  hard-boiled-egg  albumin,  on  the  contrary,  about  2.5  p.  m.  The 
rapidity  of  the  digestion  increases,  at  least  to  a  certain  point,  with  the 
quantity  of  pepsin  present,  unless  the  pepsin  added  is  contaminated  by  a 
large  quantity  of  products  of  digestion,  which  may  prevent  its  action.  The 
accumulation  of  products  of  digestion  has  a  retarding  action  on  digestion, 
althotigh,  according  to  Chittenden  and  Amerman,'  the  removal  of  the 
digestion  products  by  means  of  dialysis  does  not  essentially  change  the 
relationship  between  the  albumoses  and  true  peptones.  Pepsin  acts  slower 
at  low  temperatures  than  it  does  at  higher.  It  is  even  active  in  the  neigh- 
borhood of  0°  C,  but  digestion  takes  place  very  slowly  at  this  temperature. 
"With  increasing  temperature  the  rapidity  of  digestion  also  increases  until 
about  40°  C,  when  the  maximum  is  reached.  According  to  the  investiga- 
tions of  Flaum*  it  is  probable  that  the  relation&liip  between  albumoses  and 
peptones  remains  the  same,  irrespective  of  whether  the  digestion  took  place 

'  In  Pawlow,  1.  c,  p.  31. 

''  See  Wroblewski,  Zeitschr.  f.   physiol.   Chem.,  Bd.  21,  and  especially  Pfleiderer, 
Pflllger's  Arch.,  Bd.  66,  which  also  gives  references  to  other  works. 
^  Joum.  of  Physiol.,  Vol.  14. 
*  Zeitschr.  f.  Biologic.  Bd.  28. 


PRODUCTS  OF  PEPSIN  DIGESTION.  265 

at  a  low  or  high  temperatare  as  long  as  the  digestion  is  contlnnons  for  some 
time.  If  the  swelling  vp  of  the  profeid  is  prevented,  as  by  tlie  addition  of 
neutral  salts,  such  as  NaCl  in  sufficient  amounts,  or  by  the  addition  of  bile 
to  the  acid  liquid,  digestion  can  be  prevented  to  a  greater  or  less  extent. 
Foreign  bodies  of  different  kinds  produce  different  actions,  in  which 
naturally  the  variable  quantities  in  which  they  are  added  are  of  tlie  greatest 
importance.  Salicylic  acid  and  carbolic  acid,  and  especially  sulphates 
(Pfleiderer),  retard  digestion,  while  arsenious  acid  promotes  it  (Ciiittkx- 
DEn),  and  hydrocyanic  acid  is  relatively  indilTerent.  Alcohol  in  large 
quantities  (10^  and  above)  disturbs  the  digestion,  while  small  quantities  act 
indifferently.  Metallic  salts  in  very  small  quantities  may  indeed  sometimea 
accelerate  digestion,  but  otherwise  they  tend  to  retard  it.  The  action  of 
metallic  salts  in  different  cases  can  be  explained  in  different  ways,  but  they 
often  seem  to  form  with  proteids  insoluble  or  difficultly  soluble  combinations. 
The  alkaloids  may  also  retard  the  pepsin  digestion  (Chittenden  and 
Allen  ').  A  very  large  number  of  observations  have  been  made  in  regard 
to  the  action  of  foreign  substances  on  artificial  pepsin  digestion,  but  as  these 
observations  have  not  given  any  direct  result  in  regard  to  the  action  of  these 
same  substances  on  natural  digestion,  we  will  not  here  further  discuss  them. 
The  Products  of  the  Digestion  of  Proteids  hy  Means  of  Pepsin  and  Arid. 
In  the  digestion  of  nucleoproteids  or  nucleo-albumins  an  insoluble  residue 
of  nnclein  or  pseudo-nuclein  always  remains.  With  experiments  on  casein 
Salkowski  '  has  shown  that  the  paranuclein  first  split  off  may  be  dissolved 
by  prolonged  digestion.  Fibrin  also  yields  an  insoluble  residue,  which 
consists,  at  least  in  great  part,  of  nuclein,  derived  from  the  form-elements, 
enclosed  in  the  blood-clot.  This  residue  which  remains  in  the  digestion  of 
certain  albuminous  bodies  is  called  dyspeptone  by  ]\Ieissnkr.  In  the 
digestion  of  proteids  substances  similar  to  acid  albuminates  parapepione 
(Meissner')  antialbumnle  and  antialbiunid  (Kuhne)  nuiy  also  be 
formed.  On  separating  these  bodies  the  filtered  liquid,  neutralized  at  boil- 
ing-point, contains  albumoses  and  peptones  in  the  ordinary  sense  as  chief 
constituents,  while  the  so-called  true  peptone  of  Kuhne  may  sometimes  be 
entirely  absent,  and  in  general  is  obtained  in  quantity  worth  mentioning 
only  after  a  more  continuous  and  intensive  digestion.  The  relationship 
between  the  albumoses  and  peptones  in  the  ordinary  sense  changes  very 
much  in  different  cases  and  in  the  digestion  of  various  albuminous  bodies. 
For  instance,  a  larger  quantity  of  primary  albumoses  is  obtained  from  fibrin 
than  from  hard-boiled-egg  albumin  or  from  the  proteids  of  meat,  and  the 

'  Studies  from  the  L.ib.  Pliysiol.  Clieni.  Yale  University,  Vol.  1,  p.  76.  See  also 
Cbilteudeu  aud  Stewart,  ibid..  Vol.  3,  p.  60. 

'  PdQgcr's  Arch..  Rd.  63. 

»  The  works  of  Meissner  ou  pepsin  digestion  are  found  in  Zeitscbr.  f.  Rat.  Med., 
Bdd.  7,  8,  10,  10,  and  14. 


26G  DIGESTION. 

different  proteids,  according  to  the  researches  of  Klug,'  yield  on  pepsin 
digestion  nneqnal  quantities  of  the  various  digestive  products.  In  the 
digestion  of  unboiled  fibrin  an  intermediate  product  may  be  obtained  in  the 
earlier  stages  of  the  digestion — a  globulin  which  coagulates  at  +  55°  C. 
(Hasebroek'^).  For  information  in  regard  to  the  different  albumoses  and 
peptones  which  are  formed  in  pepsin  digestion,  the  reader  is  referred  to 
previous  pages  (34-38). 

Action  of  Pepsin  Hydrochloric  Acid  on  Other  Bodies.  The  gelatin- 
forming  sulstance  of  the  connective  tissue,  of  the  cartilage,  and  of  the  bones, 
from  which  last  the  acid  only  dissolves  the  inorganic  substances,  is  converted 
into  gelatin  by  digesting  with  gastric  juice.  The  gelatin  is  farther  changed 
so  that  it  loses  its  property  of  gelatinizing  and  is  converted  into  a  so-called 
gelatin  peptone  (see  page  56).  True  mucin  (from  the  submaxillary)  is 
dissolved  by  the  gastric  juice  and  yields  a  substance  similar  to  peptone,  and 
a  reducing  substance  similar  to  that  obtained  by  boiling  with  a  mineral 
acid.  Elastin  is  dissolved  more  slowly  and  yields  the  above-mentioned 
substances  (page  54).  Keratin  and  the  epidermis  formation  are  insoluble. 
Nucleiii/\&  not  dissolved  and  the  cell-nnclei  are  therefore  insoluble  in  gastric 
juice.  The  animal  cell-memhrane  is,  as  a  rule,  more  easily  dissolved  the 
nearer  it  stands  to  elastin,  and  it  dissolves  with  greater  difficulty  the  more 
closely  it  is  related  to  keratin.  The  m,emhrane  of  the  plant-cell  is  not  dis- 
solved.  OxyhcemogloMn  is  changed  into  hsematin  and  acid  albuminate,  the 
latter  undergoing  further  digestion.  It  is  for  this  reason  that  blood  is 
changed  into  a  dark-brown  mass  in  the  stomach.  The  gastric  juice  does 
not  act  on  fat,  but,  on  the  contrary,  on  fatty  tissue,  dissolving  the  cell- 
membrane,  setting  the  fat  free.  Gastric  jaice  has  no  action  on  starch  or 
the  simple  varieties  of  sugar.  The  statements  in  regard  to  the  ability  of 
gastric  juice  to  invert  cane-sugar  are  very  contradictory.  At  least,  this 
action  of  the  gastric  juice  is  not  constant,  and,  if  it  is  present  at  all,  it  is 
probably  due  to  the  action  of  the  acid. 

Pepsin  alone,  as  above  stated,  has  no  action  on  proteids,  and  an  acid  of 
the  intensity  of  the  gastric  juice  can  only  very  slowly,  if  at  all,  dissolve 
coagulated  albumin  at  the  temperature  of  the  body.  Pepsin  and  acid 
together  not  only  act  more  quickly,  but  qualitatively  they  act  otherwise 
than  the  acid  alone.  If  liquid  proteid  is  digested  with  hydrochloric  acid  of 
2  p.  m.,  it  is  converted  into  acid  albuminates;  but  if  pepsin  is  previously 
added  to  the  acid,  the  formation  of  syntonin  occurs  much  more  slowly 
under  the  same  conditions  (Meissner).  From  this  it  is  inferred  that  a 
part  of  the  hydrochloric  acid  is  combined  with  the  pepsin,  and  we  have  here 
a  proof  of  the  existence  of  a  paired  acid,  called  by  C.  Schmidt  pepsin 
hydrochloric  acid. 

'  Pfliiger's  Arch.,  Bd.  65. 

*  Zeitschr.  f.  pLysiol.  Chem.,  Bd.  11. 


RENNIN.  267 

It  lias  been  further  stiggcstcd  tlint  tliis  liypollielical  acid  is  possibly  defomposed  in 
digestion  into  free  pepsin  und  free  liydrociiioric  iicid,  wliicii  \n  statu  ndsrcitdi  d\9,^o\vc% 
proteids  to  :i  certain  (legrcc.  The  pepsin  set  free  reunites  with  a  new  portion  of  acid, 
forniinir  pepsin  hydrochloric  acid,  and  in  contact  witii  proteids  is  further  decomposed  as 
above  des(  libecL  It  is  hardly  necessary  to  mention  that  this  statement  is  only  an 
unproved  hypothesis. 

Rennin  or  chymosix  is  the  second  enzyme  of  tlie  gastric  juice.  It  occurs 
in  the  gastric  juice  of  man  under  physiological  conditions,  bnt  maybe  absent 
under  special  pathological  conditions,  such  as  carcinoma,  atrophy  of  the 
mucous  membrane,  and  certain  chronic  catarrhs  (Boas,  Johnson,  Klem- 
perer').  It  is  habitually  found  in  the  neutral,  watery  infusion  of  the 
fourth  stomach  of  the  calf  and  sheep,  especially  in  an  infusion  of  the  fundus 
part.  In  other  mammals  and  in  birds  it  is  seldom  found,  and  in  fishes 
hardly  ever  in  the  neutral  infusion.  In  these  cases,  as  in  man  and  the 
higher  animals,  a  rennin-forming  substance,  a  rennin  zymogen,  occurs  which 
is  converted  into  rennin  by  the  action  of  an  acid.  Rennin  or  rennin-like 
enzymes  occur  also  rather  extensively  in  the  plant  kingdom.  Certain 
micro-organisms  also  act  like  chymosin.  Parachymosin  is  the  name  given 
by  liANfj'  to  an  enzyme  differing  in  many  respects  from  the  ordinary 
rennet  ferment.  He  first  found  it  in  commercial  pepsin  preparations,  then 
in  pigs,  and  finally  also  in  human  stomachs,  where  he  claims  ordinary 
rennin  does  not  exist,  but  only  parachymosin. 

Rennin  is  just  as  diflicnlt  to  prepare  in  a  pure  state  as  the  other  enzymes. 
The  purest  rennin  enzyme  thus  far  obtained  did  not  give  the  ordinary  pro- 
teid  reactions.  On  heating  its  solution  to  G0-70°  C.  for  about  10  minutes 
it  is  more  or  less  quickly  destroyed,  depending  upon  duration  of  heating  and 
concentration.  If  an  active  and  strong  infusion  of  a  mucous  coat  in  water 
containing  3  p.  m.  HCl  is  heated  to  37-40°  C.  for  48  hours,  the  rennin  is 
destroyed,  while  the  pepsin  remains.  A  pepsin  solution  free  from  rennin 
can  be  obtained  in  this  way.  Rennin  is  characterized  by  its  physiological 
action,  which  consists  in  coagulating  milk  or  a  casein  solution  containing 
lime,  if  neutral  or  very  faintly  alkaline. 

Rennin  may  be  carried  down  by  other  precipitates  like  other  enzymes, 
and  thus  may  be  obtained  relatively  pure.  It  may  also  be  obtained,  con- 
taminated with  a  great  deal  of  proteids,  by  extracting  the  mucous  coat  of 
the  stomach  with  glycerin. 

A  comparatively  pure  solution  of  rennin  may  be  obtained  in  the  follow- 
ing way.  An  infusion  of  the  mucous  coat  of  the  stomach  in  hydrochloric 
acid  is  prepared  and  then  neutralized,  after  which  it  is  repeatedly  shaken 
with  new  quantities  of  magnesium  carbonate  until  the  pepsin  is  precipitated. 

'  A  good  review  of  the  literature  may  be  found  in  Szydlowski,  Beitrag  zur  Keuntniss 
des  Labenzym  nach  Beobachtungen  an  Siiuglingen,  Jalirb.  f.  Kinderheilkunde,  N.  F., 
Bd.  34.  See  also  Lorcher,  PflUger's  Arch.,  Bd.  69,  which  also  contains  the  pertinent 
literature. 

'  Deutsch.  med.  Wochenschr.,  1899,  No.  3. 


268  DIGESTION. 

Tlie  filtrate,  which  should  act  strongly  on  milk,  is  precipitated  by  basic 
lead  acetate,  the  precipitate  decomposed  with  very  dilate  sulphuric  acid, 
the  acid  liquid  filtered  and  treated  with  a  solution  of  stearin  soap.  The 
rennin  is  carried  down  by  the  fatty  acids  set  free,  and  when  these  last  are 
placed  in  water  and  removed  by  shaking  with  ether,  the  rennin  remains  in 
the  watery  solution. 

The  question  whether  the  parietal  cells  principally  or  these  with  the 
chief  cells  take  part  in  the  formation  of  free  acid  is  somewhat  disputed,' 
There  can  be  no  doubt  that  the  hydrochloric  acid  of  the  gastric  jnice 
originates  from  the  chlorides  of  the  blood  because,  as  is  Avell  known,  a  secre- 
tion of  perfectly  typical  gastric  juice  takes  place  in  the  stomachs  of  fasting 
or  starving  animals.  As  the  chlorides  of  the  blood  are  derived  from  the 
food,  it  is  easily  understood,  as  shown  by  Cahn,''  that  in  dogs  after  a 
sufficiently  long  common-salt  starvation  the  stomach  secreted  a  gastric  juice 
containing  pepsin,  but  no  free  hydrochloric  acid.  On  the  administration 
of  soluble  chlorides  a  gastric  juice  containing  hydrochloric  acid  was  im- 
mediately secreted.  On  the  iutroduction  of  alkali  iodides  or  bromides, 
KtJLZ,  JSTencki  and  Schoumow-Simanowski  '  have  shown  that  the  hydro- 
chloric acid  of  the  gastric  juice  is, replaced  by  HBr,  and  to  a  less  extent  by 
TIL  We  do  not  know  how  the  secretion  of  free  hydrochloric  acid  origi- 
nates. Whereas  it  used  to  be  considered  that  the  chlorides  were  decomposed 
by  an  electrolysis  or  by  organic  acids  produced  in  the  mucosa,  we  now  rather 
generally  accept  the  process  as  suggested  by  Maly. 

Malt  has  called  attention  to  the  fact  that,  on  account  of  the  presence 
of  a  large  quantity  of  free  carbon  dioxide  in  the  blood  and  the  avidity  of  the 
same,  there  must  be  present  among  the  numerous  combinations  of  acids 
and  bases  which  exist  in  the  serum  traces  of  free  hydrochloric  acid  in 
addition  to  acid  salts.  As  these  traces  of  hydrochloric  acid  are  removed 
from  the  blood  by  means  of  rapid  diffusion  by  the  glands,  the  mass-action 
of  the  carbon  dioxide  must  set  free  new  traces  of  hydrochloric  acid  in  the 
blood.  In  this  way  may  be  explained  the  secretion  in  the  blood  of  large 
quantities  of  hydrochloric  acid  from  the  chlorides,  but  the  proof  that  the 
hydrochloric  acid  set  free  passes  into  the  gastric  juice  simply  by  diffusion 
ia  missing.  Similar  processes  in  other  animal  glands  render  it  probable  that 
here,  as  in  other  cases  of  secretion,  we  have  to  deal  with  a  yet  unexplained 
specific  secretory  action  of  the  glandular  cells.     As  Schierbeck  *  has  shown 

•  See  Ileidenhain,  Pttuger's  Arch..  Bdd.  18  luul  19,  and  Ilermanu's  Haiidbucli,  Bd. 
6,  Till.  1,  "  Ahsondeiung.svorgllnge";  Klemensiewicz,  Wien.  Sitzungsber.,  Bd.  71; 
Fiiiiikel,  Pflliger's  Arcb.,  Bdd.  48  and  50  ;  Contejeau,  1.  c,  Chapter  2,  which  contains 
all  the  older  jiterature. 

«  Zeitschr.  f.  ])hysiol.  Cbem,,  Bd.  10. 

=  Kiilz,  Zeitschr.  f.  Biologie,  Bd.  23  ;  Nencki  and  Schonmow,  Arch,  des  sciences  biol. 
lie  St.  Petersbourg,  Tome  3. 

•«  Maly,  Zeitschr.  f.  physiol.  Cbem,,  Bd.  1;  Schierbeck,  Skand.  Arch.  f.  Physiol.^ 
I*,dd.  3  and  ",. 


FORM  AT  ION  OF  AVJD   IN  GASTIilV  JUICE.  269 

that  large  qnantities  of  ourbon  dioxide  are  formed  in  tlie  niiicous  membrane 
during  secretion,  it  can  be  admitted  that  this  carbon  dioxide,  by  its  avidity, 
sets  free  hydrochloric  acid  within  the  glandular  cells  from  the  chlorides  of 
the  food.     This  hydrochloric  acid  passes  then  into  the  secretion. 

L.  LiEBKHMANN  '  liiis  liik'ly  i)r()posed  ;i  new  theory  for  iIk;  sccrelion  of  liydnjcliloi  ic 
acid.  Afcordiiiu'  to  hiiu  Iccitlialhumin  occurs  in  tlie  ^l;iii(liil;ir  cflis,  and  this  coiubinis 
readily  wiih  alkalies.  Tiic  more  active  nietabolisin  in  the  glands  during  work  leads  to 
an  abundant  formation  of  carl)on  dio.\ide,  and  tliis  carbon  dioxide  by  its  mass-action  seta 
hydrochloric  acid  free  from  tbe  chlorides.  The  hydrochloric  add  passes  into  the  secre- 
tion by  dilfiision,  wliile  the  alkalies  combine  with  the  lecitlialbumin.  In  regard  to 
details  of  this  theory  we  must  refer  the  reader  to  the  original  article. 

After  a  full  meal,  when  the  store  of  pepsin  in  the  stomach  is  com- 
pletely exhausted,  ScniFF  claims  that  certain  bodies,  especially  dextrin, 
have  the  property  of  causing  a  supply  of  pepsin  in  tlie  mucous  membrane. 
This  "  charge  theory,"  though  experimentally  proved  by  several  investi- 
gators, has  nevertheless  not  yet  been  confirmed.  On  the  contrary,  the 
statement  of  Schiff  that  a  substance  forming  pepsin,  a  ^^ pepsinogat^^  or 
*^ propepsin,''^  occurs  in  the  ventricle  has  been  proved.  Langley*  has 
shown  positively  the  existence  of  such  a  substance  in  the  mucous  coat. 
This  substance,  propepsin,  shows  a  comparatively  strong  resistance  to  dilute 
alkalies  (a  soda  solution  of  5  p.  m.),  which  easily  destroy  pepsin  (Lanqley). 
Pepsin,  on  the  other  hand,  withstands  better  than  propepsin  the  action  of 
carbon  dioxide,  which  quickly  destroys  the  latter.  The  occurrence  of  a 
rennin  zymogen  in  the  mucous  coat  has  been  mentioned  above.' 

The  question  in  which  cells  the  two  zymogens,  esjiecially  the  propepsin, 
are  produced  has  been  extensively  discussed  for  several  years.  Formerly  it 
was  the  general  opinion  that  the  parietal  cells  were  pepsin  cells,  but  since 
the  investigations  of  IIeideniiain  and  his  pupils,  Laxgley  and  others, 
the  formation  of  pepsin  has  been  shifted  to  the  chief  cells.  Objections 
liave  been  presented  by  several  investigators  to  the  views  of  IIeidenhain 
that  ceitain  cells  produce  the  zymogens,  and  others  only  the  acid.* 

The  Pyloric  Secretion.  That  part  of  the  pyloric  end  of  the  dog's 
stomach  which  contains  no  fundus  glands  Avas  dissected  by  Klemensiewicz, 
one  end  being  sewed  together  in  the  shape  of  a  blind  sack  and  the  other 
sewed  into  the  stomach.  From  the  fistula  thus  created  he  was  able  to  obtain 
the  pyloric  secretion  of  a  living  animal.  This  secretion  is  alkaline,  viscous, 
jelly-like,  rich  in  mucin,  of  a  specific  gravity  of  1.009-1.010,  and  contain- 
ing 10.5-20.5  p.  m.  solids.  It  has  no  effect  on  fat,  but  acts,  though  very 
slowly,  on  starch,  converting  it  into  sugar,  and  contains  ordinarily  pepsin, 

'  Pflager's  Arch.,  Bd.  50. 

'Schiff,    "  Le9ons   sur  la  physiol.  de  la  digestion,"  1867,   Tome  2;    Langley  and 
Edkins,  Journ.  of  Physiol.,  "Vol.  7. 
'  See  foot-note  1,  page  267. 
*  See  foot-note  4,  page  268. 


270  DIGESTION. 

which  sometimes  occurs  iu  considerable  amounts.  This  hag  been  observed 
bj  Heidexhain'  in  permanent  pyloric  fistula.  Contejean  has  investi- 
gated the  pyloric  secretion  in  other  ways,  and  finds  that  it  contains  both 
acid  and  pepsin.  The  alkaline  reaction  of  the  secretions  investigated  by 
Heidenhaix  and  Klemensiewicz  is  due,  according  to  Contejean,  to  an 
abnormal  secretion  caused  by  the  operation,  because  the  stomach  readily 
yields  an  alkaline  juice  instead  of  an  acid  one  under  abnormal  conditions. 
Akerman  has  found,  in  accordance  with  Heidenhaust  and  Klemen- 
siEWicz,  that  the  pyloric  secretion  of  a  dog  was  alkaline.  Yeehaegen"  ' 
has  observed  in  human  beings  towards  the  end  of  the  ventricle  digestion 
a  fluid  not  acid  which,  according  to  him,  originates  in  the  pyloric  region. 

The  secretion  of  gastric  juice  under  different  conditions  may  vary  con- 
siderably. The  statements  of  the  quantity  of  gastric  jaice  secreted  in  a 
certain  time  are  therefore  so  unreliable  that  they  need  not  be  taken  into 
account. 

The  Chyme  and  the  Digestion  in  the  Stomach.  By  means  of  the  chemi- 
cal irritation  caused  by  the  food,  a  copious  secretion  of  gastric  juice 
occurs.  /  The  food  is  there  by  freely  mixed  with  liquid  and  is  gradually 
converted  into  a  pulpy  mass,  called  the-  chyme.  This  mass  is  acid  in 
reaction,  and,  with  the  exception  of  the  interior  of  large  pieces  of  meat  or 
other  solid  foods,  the  chyme  is  acid  throughout.  The  transformation 
products  of  the  digestion  of  proteids  and  carbohydrates  can  be  detected  in 
the  chyme;  likewise  more  or  less  changed  undigested  residues  of  swallowed 
food,  which  indeed  form  the  chief  mass  of  the  chyme. 

In  the  chyme  morsels  of  meat  more  or  less  changed  are  found  which, 
when  unboiled  meat  is  partaken  of,  may  be  much  swollen  and  slippery. 
Muscle  and  cartilage  are  also  often  swollen  and  slippery,  while  pieces  of 
boxe  sometimes  show  a  rough  and  uneven  surface  after  the  digestion  has 
continued  for  some  time,  which  depends  upon  the  fact  that  the  gelatinous 
substances  of  the  bone  are  attacked  more  quickly  by  the  gastric  jnice  than 
the  earthy  parts.  Milk  coagulates  in  the  stomach  by  the  combined  action 
of  the  rennin  and  the  acid,  but  in  certain  cases  by  the  action  of  the  acid 
alone.  From  the  relative  quantities  of  the  swallowed  milk  to  the  other 
food  either  large  and  solid  lumps  of  cheese  are  formed  or  smaller  lumps  or 
grains  which  are  divided  in  the  pulpy  mass.  Cow's  milk  regularly  yields 
large,  solid  masses  or  lumps;  human  milk  gives,  on  the  contrary,  a  fine, 
loose  coagulum  or  a  fine  precipitate  which  is  immediately  dissolved  in  part 
by  the  acid  liquid. 

?)REAI),  especially  when  not  too  fresh,  is  converted  rather  easily  into  a 
pulpy  mass  in  the  stomach.     Other  vegetable  foods,  such   as   potatoes, 


»  Heidenhain  and  Klemensiewicz,  1.  c;   Coutejean,  1.   c,  Chapter  2,  and  Skand. 
Arch.  f.  Physiol.,  Bd.  6  ;  Akerman,  ibid.,  Bd.  5  ;  Vorhaegen,  1.  c. 


CHYME.  271 

may,  if  not  siifticiently  masticated,  often  be  found  in  the  contents  of  the 
stomach,  very  little  changed,  several  hours  after  a  meal. 

Starck  is  not  converted  into  sngar  by  the  gastric  juice,  but  in  the  first 
phases  of  the  Tligestion,  before  a  large  quantity  of  hydrochloric  acid  has 
accumulated,  it  seems  that  the  action  of  the  saliva  continues,  and  therefore 
the  presence  of  dextrin  and  sugar  can  be  detected  in  the  contents  of  the 
stomach.  Besides  this  the  carbohydrates  in  the  stomach  may  in  part 
undergo  a  lactic-acid  fermentation,  caused  by  the  micro-organisms  present. 

The  FATS  which  are  not  fluid  at  the  ordinary  temperature  melt  in  the 
stomach  at  the  temperature  of  the  body  and  become  fluid.  In  the  same 
way  the  fat  of  the  fatty  tissues  is  set  free  in  the  stomach  by  the  gastric  juice 
which  digests  the  cell-membrane.  The  gastric  juice  itself  seems  to  have  no 
action  on  fats.'  The  soluble  salts  of  the  food  naturally  are  found  dissolved 
in  the  liquids  of  the  contents  of  the  stomach ;  but  the  insoluble  salts  may 
also  be  dissolved  by  the  acid  of  the  gastric  juice. 

Since  the  hydrochloric  acid  of  the  gastric  juice  prevents  the  contents  of 
the  stomach  from  fermenting  with  the  generation  of  gas,  those  gases  which 
occur  in  the  stomach  probably  depend,  at  least  in  great  measure,  upon  the 
swallowed  air  and  saliva,  and  upon  those  gases  generated  in  the  intestine 
and  returned  through  the  pyloric  valve.  Plaxer  found  in  the  stomach- 
gases  of  a  dog  G6-68^  N,  25-33j^  CO,,  and  only  a  small  quantity,  0.8-6.1«^. 
of  oxygen.  Schierbeck*  has  shown  that  apart  of  the  carbon  dioxide  i. 
formed  by  the  mucous  membrane  of  the  stomach.  The  tension  of  the 
carbon  dioxide  in  the  stomach  corresponds,  according  to  him,  to  30-40  mm. 
Ilg  in  the  fasting  condition.  It  increases  after  partaking  food,  independ- 
ently of  the  kind  of  food,  and  may  rise  to  130-140  mm.  Ilg  during  diges- 
tion. The  curve  of  the  carbon-dioxide  tension  in  the  stomach  is  the  same 
as  tlie  curve  of  acidity  in  the  different  phases  of  digestion,  and  Scitiekbeck 
has  also  found  that  the  carbon- dixoide  tension  is  considerably  increased  by 
pilocarpin,  but  diminished  by  nicotin.  According  to  him,  the  carbon 
dioxide  of  the  stomach  is  a  product  of  the  activity  of  the  secretory 'cells. 

According  as  the  food  is  finely  or  coarsely  divided  it  passes  sooner  or 
later  through  the  pylorus  into  the  intestine.  From  Busch's  observations 
on  a  human  intestinal  fstula,  it  required  generally  15-30  minutes  after 
eating  for  undigested  food  to  pass  into  the  upper  part  of  the  small  intes- 
tine. In  a  case  of  duodenal  fistula  in  a  human  being  observed  by  Kuhne, 
he  saw,  ten  minutes  after  eating,  uncurdled  but  still  coagulable  milk  and 
small  pieces  of  meat  pass  out  of  the  fistula.  The  time  in  which  the  stomach 
unburdens  itself  of  its  contents  depends,  however,  upon  the  rapidity  with 

'  See  Contejean,  "  Sur  la  digestion  gasUique  de  la  graisse,"  Arch,  de  Physiol.  (5), 
Tome  6. 

'  Planer,  "Wien.  Sitzungsber.,  Bd.  42;  Schierbeck,  1.  c. 


272  DIGESTION. 

which  the  quantity  of  hydrochloric  acid  increases,  for  it  seems  to  act  as  a 
sort  of  irritant  and  canses  the  opening  of  the  pylorns.  Many  other  condi- 
tions also  come  into  play,  namely,  the  activity  of  the  gastric  juice,  the 
quantity  and  character  of  the  food,  etc.,  etc.,  and  therefore  the  time 
required  to  empty  the  stomach  must  be  variable.  Eichet  observed  in  a 
case  of  stomachic  fistula  that  in  man  the  quantity  of  food  which  is  in  the 
stomach  the  first  three  hours  is  not  essentially  changed,  but  that  in  the 
course  of  a  quarter  of  an  hour  nearly  all  is  driven  out,  so  that  only  a  small 
residue  remains.  Kuhne  has  made  about  the  same  observations  on  dogs 
and  human  beings.  He  found,  indeed,  in  dogs  that  in  the  first  hour  small 
quantities  of  meat  passed  into  the  intestine  every  ten  minutes;  but  he  also 
observed  that  in  dogs,  on  an  average,  about  five  hours  after  eating,  in  man 
somewhat  earlier,  a  free  emptying  into  the  intestine  takes  place.  Accord- 
ing to  other  investigators,  the  emptying  of  the  human  stomach  does  not 
take  place  suddenly,  but  gradually.  Beaumont  '  found  in  his  extensive 
observations  on  the  Canadian  hunter,  St.  Martin",  that  the  stomach,  as  a 
rule,  is  emptied  li-S^  hours  after  a  meal,  depending  upon  the  character  of 
the  food. 

The  time  in  which  different  foods  leave  the  stomach  depends  also  upon 
their  digestibility.  In  regard  to  the  unequal  digestibility  in  the  stomach 
of  foods  rich  in  proteids,  which  really  form  the  object  of  the  action  of  the 
gastric  juice,  a  distinction  must  be  made  between  the  rapidity  with  which 
the  proteids  are  converted  into  albumoses  and  peptones  and  the  rapidity 
with  which  the  food  is  converted  into  chyme,  or  at  least  so  prepared  that  it 
may  easily  pass  into  the  intestine.  This  distinction  is  especially  important 
from  a  practical  standpoint.  "When  a  proper  food  is  to  be  decided  upon  in 
cases  of  diminished  stomachic  digestion,  it  is  important  to  select  such  foods 
as,  independent  of  the  difficulty  or  ease  with  which  their  proteid  is  pepton- 
ized, leave  the  stomach  easily  and  quickly,  and  which  require  as  little  action 
as  possible  on  the  part  of  this  organ.  From  this  point  of  view  those  foods, 
as  a  rule,  are  most  digestible  which  are  fluid  from  the  start  or  may  be  easily 
liquefied  in  the  stomach;  but  these  foods  are  not  always  the  most  digestible 
in  the  sense  that  their  proteid  is  most  easily  peptonized.  As  an  example, 
hard-boiled  white  of  egg  is  more  easily  peptonized  than  fluid  white  of  egg 
at  a  degree  of  acidity  of  1-2  p.  m.  IICl;''  nevertheless  we  consider,  and 
justly,  that  an  unboiled  or  soft-boiled  egg  is  easier  to  digest  than  a  hard- 
boiled  one.  Likewise  uncooked  meat,  when  it  is  not  chopped  very  fine,  is 
not  more  quickly  but  more  slowly  peptonized  by  the  gastric  juice  than  the 
cooked,  but  if  it  is  divided  sufficiently  fine  it  is  often  more  quickly  pepton- 
ized than  the  cooked. 

'  Busch,  Vircliow's  Arch.,  Bd.  14  ;  Kuhuc,  Lebrb.  d.  physiol.  Chem.,  S.  53;  Richet, 
1.  c. ;  Beaumont,  ].  c. 

'  Wawrinsky,  Maly's  Jahresber.,  Bd.  3. 


STOMACniC  DIGESTION.  273 

The  greater  or  less  facility  with  which  the  different  albuminous  foods 
are  peptonized  by  the  gastric  juice  has  been  comparatively  little  stndicd, 
and  as  the  conditions  in  the  stomach  are  more  complicated,  results  obtained 
with  artificial  gastric  juice  are  often  of  no  value  for  the  practising  physician 
and  should  in  any  case  be  used  only  with  the  greatest  caution.  Under  these 
circumstances  we  cannot  enter  more  deeply  into  this  subject,  but  the  reader 
is  referred  to  text-books  on  dietetics  and  the  study  of  foods. 

As  our  knowledge  of  the  digestibility  of  the  different  foods  in  the 
stomach  is  slight  and  dubious,  so  also  our  knowledge  of  the  action  of  other 
bodies,  such  as  alcoholic  drinks,  bitter  principles,  spices,  etc.,  on  the  natural 
digestion  is  very  uncertain  and  imperfect.  The  difficulties  which  stand  in 
the  way  of  this  kind  of  investigation  are  very  great,  and  therefore  the  results 
obtained  thus  far  are  often  ambiguous  or  conflict  with  each  other.  For 
example,  certain  investigators  have  observed  that  small  quantities  of  alcohol 
or  alcoholic  drinks  do  not  prevent  but  rather  facilitate  digestion;  others 
observe  only  a  disturbing  action;  while  other  investigators  believe  to  have 
found  that  the  alcohol  first  acts  somewhat  as  a  disturbing  agent,  but  after- 
wards, when  it  is  absorbed,  it  produces  an  abundant  secretion  of  gastric 
juice,  and  thereby  facilitates  digestion  (Gluzinski,  Chittijndex^). 

The  digestion  of  sundry  foods  is  not  dependent  on  one  organ  alone,  but 
divided  among  several.  For  this  reason  it  is  to  be  expected  that  the  various 
digestive  organs  can  act  for  one  another  to  a  certain  point,  and  that  there- 
fore the  work  of  the  stomach  could  be  taken  up  more  or  less  by  the 
intestine.  This  in  fact  is  the  case.  Thus  the  stomach  of  a  dog  has  been 
almost  completely  extirpated  (Czerxy,  Caryallo,  and  Panchon),  and 
also  that  part  necessary  in  the  digestive  process  has  been  eliminated  by 
plugging  the  pyloric  opening  (Ludwig  and  Ogata),  and  in  both  cases  it 
was  possible  to  keep  the  animal  alive,  well  fed,  and  strong.  This  is  also 
true  for  human  beings.'  In  these  cases  it  is  evident  that  the  digestive  work 
of  the  stomach  was  taken  up  by  the  intestine ;  but  all  food  cannot  be  digested 
in  these  cases  to  the  same  extent,  and  connective  tissue  of  meat  in  especial 
is  sometimes  found  to  a  considerable  extent  undigested  in  the  excrements. 

A  cat  whose  slomach  Carvallo  and  Panciion  had  exiirpated  entire!}'  livcl  onl\'  six 
montlis,  but  tliiswas  caused  by  its  not  wnnting  to  take  food.  These  investigators  find  it 
probable  that  the  stomach  is  necessary  for  the  sensation  of  the  want  of  food. 

In  order  to  judge  of  the  role  of  the  stomach  in  digestion  the  amount  of 
the  digestion  products  in  the  stomach  has  been  determined.     These  deter- 

'  Gluzinski,  Deutsch.  Arch.  f.  klin.  Med..  Bd.  39;  Chittenden,  Ceutralbl.  f.  d.  med. 
Wissensch.,  1889;  and  Chittenden  and  Mendel,  and  others,  Amer.  Journ.  of  Physiol., 
Vol.  1. 

*  Czerny,  cited  from  Bunge,  Lehrbuch  d.  physiol.  u.  Path.  Chem.,  3.  Aufl. ;  Carvallo 
and  Panchon,  Arch.  d.  Physiol.  (5).  Tome  7  ;  Ogata,  Du  Bois-Iieymond's  Arch.,  1883. 
In  regard  to  a  human  case  see  Schlatter  in  Wroblewski,  Centralbl.  f.  Physiol.,  Bd  11, 
S.  665. 


274  DIGESTION. 

minations,  part  on  man  and  part  on  animals,  have  led,  as  is  to  be  expected^ 
to  varying  results  (Cahn",  Ellenbekger  and  Hofmeistee,  CniTTENDEir 
and  Amerman  '), 

It  is,  however,  quite  generally  assumed  that  no  peptonization  of  the 
proteids  worth  mentioning  occurs  in  the  stomach,  and  that  the  albuminous 
foods  are  only  prepared  in  the  stomach  for  the  real  digestive  processes  in  the 
intestine.  That  the  stomach  serves  in  the  first  place  as  a  storeroom  follows 
from  its  shape,  and  this  function  is  of  special  value  in  certain  new-born 
animals,  for  instance  in  dogs  and  cats.  In  these  animals  the  secretion  of 
the  stomach  contains  only  hydrochloric  acid  but  no  pepsin,  and  the  casein 
of  the  milk  is  converted  by  the  acid  alone  into  solid  lumps  or  a  solid 
coagulum  which  fills  the  stomach.  Small  portions  of  this  coagulum  pass 
into  the  intestine  only  little  by  little,  and  an  overburdening  of  the  intestine 
is  thus  prevented.  In  other  animals,  such  as  the  snake  and  certain  fishes, 
which  swallow  their  food  entire,  it  is  certain  that  the  major  part  of  the 
process  of  digestion  takes  place  in  the  stomach.  The  importance  of  the 
stomach  in  digestion  cannot  at  once  be  decided.  It  varies  for  difi'erent 
animals/and  it  may  vary  in  the  same  animal,  depending  upon  the  division 
of  the  food,  the  rapidity  with  which  the  peptonization  takes  place,  the  more 
or  less  rapid  increase  in  the  amount  of  hydrochloric  acid,  and  so  on. 

It  is  a  well-known  fact  that  the  contents  of  the  stomach  may  be  kept 
without  decomposing  for  some  time  by  means  of  hydrochloric  acid,  while, 
on  the  contrary,  when  the  acid  is  neutralized  a  fermentation  commences  by 
which  lactic  acid  and  other  organic  acids  are  formed.  According  to  Cohn 
an  amount  of  hydrochloric  acid  more  than  0.7  p.  m.  completely  arrests 
lactic  acid  fermentation,  even  under  otherwise  favorable  circumstances,  and 
according  to  Strauss  and  Bialocour^  the  limit  of  lactic  acid  fermentation 
lies  at  1.2  p.  m.  hydrochloric  acid  united  to  organic  bodies.  The  hydro- 
chloric acid  of  the  gastric  juice  has  unquestionably  an  anti-fermentive 
action,  and  also,  like  dilute  mineral  acids,  an  antiseptic  action.'  This 
action  is  of  importance,  as  many  disease  micro-organisms  may  be  destroyed 
by  the  gastric  juice.  The  common  bacillus  of  cholera,  certain  streptococci, 
etc.,  are  killed  by  the  gastric  juice,  while  others,  especially  as  spores,  are 
unacted   upon.'     The  fact  that  gastric  juice  can  diminish  or  retard   the 

1  Calm,  Zeitschr.  f.  kliii.  Med.,  Bd.  12;  Ellenberger  and  Hofmeister,  Du  Bois-Rey- 
rnoiid's  Arch.,  1890  ;  Chitteuden  and  Amermau,  Journ  of  Physiol.,  Vol.  14. 

'  Cohu,  Zeitschr.  f.  physiol.  Chem.,  Bd.  14 ;  Strauss  and  Bialocour,  Zeitsclir.  f.  klin. 
Med.,  Bd.  28. 

8  See  Kuhne,  Lehrbuch,  S.  57  ;  Bunge,  Lehrbuch,  4.  Aufl.,  S.  148  and  159  ;  F.  Cohu, 
1.  c;  Hirschfeld,  Pfliiger's  Arch..  Bd.  47. 

*  In  regard  to  the  action  of  gastric  juice  on  pathogenic  microbes  we  refer  the  reader 
to  handbooks  of  Bacteriology. 


AUTO  DIG KSTION  OF   THE  STOMACH.  275 

action  of  certain  toxalbnniins,  such  as  tetanotoxin  and  diphtheria  toxin,  is 
also  of  great  interest  (Xencki,  Sieijer,  and  SciioiMOW  '). 

Because  of  this  antifermentive  and  antitoxic  action  of  gastric  juice  it  is 
considered  tliat  the  chief  importance  of  the  gastric  juice  lies  in  its  antiseptic 
action.  The  fact  that  intestinal  putrefaction "  is  not  increased  on  the 
extir])ation  of  the  stomach,  as  derived  from  exi)eriments  made  on  man  and 
animals,  does  not  uphold  this  view. 

After  death,  if  the  stomach  still  contains  food,  auto-digestion  goes  on 
not  only  in  the  stomach,  but  also  in  the  neighboring  organs,  during  the 
slow  cooling  of  the  body.  This  leads  to  the  question,  why  does  the  stomach 
not  digest  itself  during  life  ?  Ever  since  Pavy  has  shown  tiiat  after  tying 
the  smaller  blood-vessels  of  the  stomach  of  dogs  the  corresponding  part  of 
the  mncons  membrane  was  digested,  efforts  have  been  made  to  find  the 
cause  in  the  neutralization  of  the  acid  of  the  gastric  juice  by  the  alkali  of 
the  blood.  That  the  reason  for  the  non-digestion  during  life  is  to  be  sought 
for  in  the  normal  circulation  of  the  blood  cannot  be  contradicted;  but  the 
reason  is  not  to  be  sought  in  the  neutralization  of  the  acid.  The  recent 
investigations  of  Fermi,  Mathes,  and  Otte  '  show  that  the  blood  circula- 
tion acts  in  an  indirect  manner  by  the  normal  nourishment  of  the  cell 
protoplasm,  and  this  is  the  reason  why  the  living  protoplasm  acts  unlike 
dead  protojilasm  on  the  digestive  fluids  of  the  stomach  or  the  intestine. 
Still  we  do  not  know  on  what  this  resistance  of  the  living  protoplasm  is 
based. 

Under  pathological  conditions  irregularities  in  the  secretion  as  well  as  in 
the  absorption  and  in  the  mechanical  work  of  the  stomach  may  occur. 
Pepsin  is  almost  always  present,  but  the  absence  of  the  rennin,  as  above 
stated,  may  occur  in  many  cases  (Boas,  Johnson,  Kle]\[Perer  *).  In 
regard  to  the  acid,  it  should  be  mentioned  that  sometimes  this  secretion 
may  be  increased  so  that  an  abnormally  acid  gastric  juice  is  secreted,  and 
sometimes  may  be  decreased  so  that  little  if  any  hydrochloric  acid  is 
secreted.  A  hypersecretion  of  acid  gastric  juice  sometimes  occurs.  In 
the  secretion  of  too  little  hydrochloric  acid  the  same  conditions  appear  as 
after  the  neutralization  of  the  acid  contents  of  the  stomach  outside  of  the 
organism.  Fermentation  processes  now  appear  in  which,  besides  lactic  acid, 
there  appear  also  volatile  fatty  acids,  such  as  butyric  and  acetic  acids,  etc., 
and  gases  like  hydrogen.  These  fermentation  products  are  therefore  often 
found  in  the  stomach  in  cases  of  chronic  catarrh  of  the  stomach,  which 

'  Centralbl.  f.  Bakteriologie,  etc.,  Bd.  23. 

'  See  Carvallo  and  Paclioii,  1.  c,  and  Schlatter  in  Wroblewski,  1.  c. 

="  Pavy,  Phil.  Transactions,  Vol.  153,  Part  1,  and  Guy's  Hospital  Reports,  Vol.  13; 
Otte,  Travaii.x  du  laboratoire  de  I'lnstitut  de  Physiol,  de  Li(>ge,  Tome  5,  1896,  which 
also  contains  the  literature. 

••  See  foot-note  1,  page  267. 


276  DIGESTION. 

may  give  rise  to  belching,  pyrosis,  and  other  symptoms.  According  to 
Boas  the  appearance  of  lactic  acid  is  characteristic  of  carcinoma  of  the 
stomach,  bnt  this  is  denied  by  others. 

Among  the  foreiga  subslauces  fouud  in  the  contents  of  the  stomach  we  have  ukea, 
or  ammonium  carbonate  derived  therefrom  in  unemia  ;  blood,  which  generally  forms 
a  dark-brown  mass  throuoh  the  presence  of  liaemalin,  due  to  the  action  of  the  gastric 
juice  ;  bile,  which,  especially  during  voniiiing,  easily  finds  its  way  through  the  pylorus 
into  the  stomach,  but  whose  presence  seems  to  be  without  importance. 

If  it  is  desired  to  test  the  gastric  juice  or  the  contents  of  the  stomacli 
for  j;e;;sm,  fibrin  may  be  employed.  If  this  is  thoroughly  washed  immedi- 
ately after  beating  the  blood,  well  pressed  and  placed  in  glycerin,  it  may  be 
kept  in  serviceable  condition  an  indefinitely  long  time.  The  gastric  juice 
or  the  contents  of  the  stomach — the  latter,  if  necessary,  having  been 
previously  diluted  with  1  p.  m.  hydrochloric  acid — is  filtered  and  tested 
with  fibrin  at  ordinary  temperature.  (It  must  not  be  forgotten  that  a 
control  test  must  be  made  with  acid  alone  and  another  portion  of  the  same 
fibrin.)  If  the  fibrin  is  not  noticeably  digested  within  one  or  two  hours,  no 
pepsin  is  present,  or  at  most  there  are  only  slight  traces. 

In  testing  for  rennin  the  liquid  must  be  first  carefully  neutralized.  To 
10  c.c.  unboiled,  amphoteric  (not  acid)  cow's  milk  add  1-2  c.c.  of  the  fil- 
tered neutralized  liquid.  In  the  presence  of  rennin  the  milk  should  coagu- 
late to  a  solid  mass  at  the  temperature  of  the  body  in  the  course  of  10-20 
minutes  without  changing  its  reaction.  If  the  milk  is  diluted  too  much  by 
the^ddition  of  the  liquid  of  the  stomach,  only  coarse  flakes  are  obtained 
and  no  solid  coagulum.  Addition  of  lime-salts  is  to  be  avoided,  as  they  in 
great  excess  may  produce  a  partial  coagulation  even  in  the  absence  of  ren- 
nin. 

In  many  cases  it  is  especially  important  to  determine  the  degree  of  acid- 
ity of  the  gastric  juice.  This  may  be  done  by  the  ordinary  titration 
methods.  Phenol  phthalein  must  not  be  used  as  an  indicator,  for  we  get 
too  high  results  in  the  presence  of  large  quantities  of  proteids.  Good 
results  may  be  obtained,  on  the  contrary,  by  using  very  delicate  litmus 
paper.  As  the  acid  reaction  of  the  contents  of  the  stomach  may  be  caused 
simultaneously  by  several  acids,  still  the  degree  of  acidity  is  here,  as  in 
other  cases,  expressed  in  only  one  acid,  e.g.,  HCl.     Generally  the  acidity 

N 
is  designated  by  tlie  number  of  c.c.  of  —  caustic  soda  which  is  required  to 

neutralize  the  several  acids  in  100  c.c.  of  the  liquid  of  the  stomach.     An 

acidity  of  43^  means  that  100  c.c.  of  the  liquid  of  the  stomach  required 

N 
43  c.c.  of  —  caustic  soda  to  neutralize  it. 

The  acid  reaction  may  be  partly  due  to  free  acid,  partly  to  acid  salts 
(monophosphates),  and  partly  to  both.  According  to  Leo'  we  can  test  for 
acid  phosphates  by  calcium  carbonate,  which  is  not  neutralized  therewith, 
while  the  free  acids  are.  If  the  gastric  content  has  a  neutral  reaction  after 
shaking  with  calcium  carbonate  and  the  carbon  dioxide  is  driven  out  by  a 
current  of  air,  then  it  contains  only  free  acid;  if  it  has  an  acid  reaction, 
then  acid  phosphates  are  present;  and  if  it  is  less  acid  than  before,  it  con- 

'  Ceutralbl.  f.  d.  mod.  Wissensch.,  1889,  S.  481,  and  Pfliiger's  Arch.,  Bd.  48,  S.  614. 


KXAMINAIION  OF  TUE  GASTRIC  CONTENTS.  277 

tains  both  free  acid  and  acid  j)liospliate.  This  method  can  also  be  ap])lied 
in  the  estiniation  of  free  acid  (see  below). 

It  is  also  important  to  be  able  to  ascertain  the  nature  of  the  acid  or 
acids  occurrin;^  in  the  contents  of  the  stomach.  For  this  jjiirpose,  and 
es|)ecially  for  the  detection  of  free  hydrochloric  acid,  a  great  number  of 
color  reactions  have  been  proposed,  wliich  are  all  based  U])0U  the  fact  that 
the  coloring  sub^tiince  gives  a  characteristic  color  with  very  small  quantities 
of  hydrochloric  acid,  while  lactic  acid  and  the  other  organic  acids  do  not 
give  these  colorations,  or  only  in  a  certain  concentration,  which  can  hardly 
exist  in  the  contents  of  the  stomach.  These  reagents  are  a  mixture  of 
Finiiuc  ACETATE  and  potassum  sllpiiocyanide  solution  (3Ioiik\s  rciigent 
has  been  modified  by  several  investigators),  metiiylanilix-violet,  tko- 
p.EOLix  00,  Congo  ked,  malachite-green,  piiLOPtOGLUCiN-VANiLLiN, 
BENZOPURPURIN  6  B,  and  others.  As  reagents  for  free  lactic  acid  Uefel- 
WANN  suggests  a  strongly  diluted,  amethyst-blue  solution  of  ferric  chlo- 
ride and  CARBOLIC  acid  or  a  strongly  dihited,  nearly  colorless  solution  of 
FERRIC  CHLORIDE.  These  give  a  yellow  with  lactic  acid,  but  not  with 
hydrochloric  acid  or  with  volatile  fatty  acids. 

The  value  of  these  reagents  in  testing  for  free  hydrochloric  acid  or  lactic 
acid  is  still  disputed.'  Among  the  reagents  for  free  hydrochloric  acid, 
Moiir's  test  (even  though  not  very  delicate),  Gunzrurg's  test  with  phloro- 
glucin-vanillin,  and  the  test  with  tropieolin  00,  performed  in  moderate  heat 
as  suggested  by  Boas,  seem  to  be  the  most  valuable.  If  these  tests  give 
positive  results,  then  the  presence  of  hydrochloric  acid  may  be  considered 
as  proved.  A  negative  result  does  not  eliminate  the  presence  of  hydro- 
chloric acid,  as  the  delicacy  of  these  reactions  has  a  limit,  and  also  the 
simultaneous  presence  of  proteid,  peptones,  and  other  bodies  influences  the 
reactions  more  or  less.  The  reactions  for  lactic  acid  may  also  give  negative 
results  in  the  presence  of  comparatively  large  quantities  of  hydrochloric 
acid  in  the  liquid  to  be  tested.  Sugar,  sulphocyanides,  and  other  bodies 
may  act  with  these  reagents  similarly  to  lactic  acid. 

In  testing  for  lactic  acid  it  is  safest  to  shake  the  material  w^th  ether  and 
test  the  residue  after  the  evaporation  of  the  ether.  On  the  evaporation 
of  the  ether  it  may  be  tested  in  several  ways.  Boas  '  utilized  the  property  of 
lactic  acid  of  being  oxidized  into  aldehyde  and  formic  acid  on  careful  oxida- 
tion with  sulphuric  acid  and  manganese  dioxide.  The  aldehyde  is  detected 
by  its  forming  iodoform  with  an  alkaline  iodine  solution  or  by  its  forming 
aldehyde  mercury  Avith  Xessler's  reagent.     The  quantitative  estimation 

N 
consists  in  the  formation  of  iodoform  with  —  iodine  solution  and  canstic 

potash,  adding  an  excess  of  hydrochloric  acid  and  titrating  with  a  —  sodium 

arsenite  solution,  and  retitrating  with  iodine  solution,  after  the  addition  of 
starch-paste,  until  a  blue  coloration  is  obtained.  Tiiis  method  presupposes 
the  use  of  ether  entirely  free  from  alcohol. 

In  order  to  be  able  to  correctly  judge  of  the  value  of  the  different 
reagents  for  free  hydrochloric  acid,  it  is  naturally  of  greatest  importance  to 

'  In  regard  to  the  extensive  liternture  on  this  (piestion  we  refer  to  v.  Jaksch ,  Klinische 
Diagiiostik  innerer  Krankiieiten.  4.  Aufl..  189G   Seclion  5. 

'  Deutsch.  lued.  Wochenschr.,  1893,  and  MUnclieucr  mod.  Wochenschr.,  1893. 


278  DIGESTION. 

be  clear  in  regard  to  what  we  mean  by  free  hydrochloric  acid.  It  is  a  well- 
known  fact  that  hydrochloric  acid  combines  with  proteids,  and  a  consider- 
able part  of  the  hydrochloric  acid  may  therefore  exist  in  the  contents  of 
the  stomach,  after  a  meal  rich  in  proteids,  in  combination  with  proteids. 
This  hydrochloric  acid  combined  with  proteids  cannot  be  considered  as  free, 
and  it  is  for  this  reason  that  certain  investigators  consider  such  methods  as 
those  of  Leo  and  Sjoqvist,  which  will  be  described  below,  as  of  little 
value.  However,  it  must  be  remarked  that,  according  to  the  unanimous 
experience  of  many  investigators,  the  hydrochloric  acid  combined  with  pro- 
teids is  physiologically  active.  Those  reactions  (color  reactions)  which  only 
respond  to  actually  free  hydrochloric  acid  do  not  show  the  physiologically 
active  hydrochloric  acid.  The  suggestion  of  determining  the  "  physiologi- 
cally active"  hydrochloric  acid  instead  of  the  "free"  seems  to  be  correct 
in  principle;  and  as  the  conceptions  of  free  and  of  physiologically  active 
hydrochloric  acid  are  not  the  same  it  must  always  be  clear  whether  we 
want  to  determine  the  actually  free  or  the  physiologically  active  hydro- 
chloric acid  before  we  judge  of  the  value  of  a  certain  reaction. 

As  the  above-mentioned  reactions  for  hydrochloric  acid  and  organic 
acids  are  not  sufficient  in  exact  investigations,  still  they  may  serve  in  mauy 
cases  for  clinical  purposes,  and  it  will  suffice  to  refer  the  reader  to  other 
text-books,  and  especially  to  ^^Klinische  Diagnostik  i7inerer  Kranlcheit en .,'''' 
by  R.  V.  Jaksch,  4th  edition,  1896,  for  the  performance  and  the  relative 
value  of  these  tests. 

Among  the  many  methods  suggested  for  the  quantitative  estimation  of 
hydrc/chloric  acid  not  combined  with  inorganic  bases,  the  two  following  are 
the  most  trustworthy: 

The  method  of  E.  Morner  and  Sjoqvist  depends  on  the  following  prin- 
ciple: When  the  gastric  juice  is  evaporated  to  dryness  with  barium  carbon- 
ate and  then  calcined  the  organic  acids  burn  up  and  give  insoluble  barium 
carbonate,  while  the  hydrochloric  acid  forms  soluble  barium  chloride. 
From  the  quantity  of  this  the  original  amount  of  hydrochloric  acid  can  be 
calculated.  10  c.c.  of  the  filtered  contents  of  the  stomach  is  mixed  in  a 
small  platinum  or  silver  dish  with  a  knife-point  of  barium  carbonate  free 
from  chlorides,  and  evaporated  to  dryness.  The  residue  is  burnt  and 
allowed  to  glow  for  a  few  minutes.  The  cooled  carbon  is  gently  rubbed  with 
water  and  completely  extracted  with  boiling  water,  and  the  filtrate  (about 
•50  c.c.)  precipitated  by  ammonium  chromate  after  the  addition  of  ammo- 
nium acetate  and  acetic  acid  and  boiling.  The  carefully  collected  precipitate 
is  washed  and  dissolved  in  water  by  the  aid  of  a  little  liCl,  KI,  and  hydro- 
chloric acid  added  and  titrated  with  hyposulphite  solution.  The  reactions 
take  place  as  follows:  4HC1  +  2BaC0,  =  2BaCl,  +  211,0  +  2C0,;  2BaCl, 
+  2(NIIJ,CrO,  =  2BaCrO,  +  4NH,Ci;  2BaCrO,  -f  16IICI  +  6KI=2BaCl, 
+  Cr^Cl.  +  811,0  H-  6KCI  -f  31,;  and  31,  +  6Na,S,03  =  6NaI  +  3Na,S,0,. 
Each  c.c.  of  the  hyposulphite  corresponds  to  3  mgm.  IICl.  Complete 
directions  for  the  necessary  solutions  and  for  the  performance  of  the  method 
may  be  found  in  Sjoqvist,  Zeitschr.  f.  klin.  Med.,  Bd.  32. 

Leo's  Method.^     10  c.c.  of  the  filtered  gastric  juice  is  treated  with  about 

N 
5  c.c.   calcium-chloride  solution,  and  the  total  acidity  determined  by  — 

'  Centralbl.  f.  d.  med.  Wisseusch.,  1889,  S.  481. 


EXAMINATION  OF  THE  GASTlilC  CONTENTS.  279 

caustic-soda  solution,  using  litmus  as  the  indicator.  Then  shake  15  c.c.  of 
the  same  gastric  juice  with  i)ure,  finely  j)Owdered  calcium  carbonate,  fdter 
through  a  dry  filter,  remove  the  carl)on  dioxide  from  the  filtrate  by  means 
of  a  current  of  air,  measure  off  exactly  10  c.c.  of  the  liquid  and  treat  with 
5  c.c.  of  the  calcium-chloride  solution,  and  add  litmus  and  titrate  again. 
The  ditlerence  between  the  two  titrations  shows  the  acidity  due  to  free  acid. 
Any  fatty  acids  present  may  be  shaken  out  from  another  portion  by  ether 
and  the  acidity  determined  on  the  spontaneous  evaporation  of  the  ether. 

Other  methods  have  been  proposed  by  Caiin  and  v.  MEiuxa,  Hoffmann, 
Winter  and  IIayem,  and  Bkatn.  According  to  Kossleh  '  the  three  last- 
mentioned  methods  are  not  quite  serviceable. 

Leo  '  has  recently  made  strong  objections  to  the  usefulness  of  Morner 
and  Sjoqvist's  method.  lie  contradicts  the  correctness  of  S.ioqvist's 
statement  in  regard  to  the  extent  of  dissociation  in  various  mixtures  of 
liydrochloric  acid  and  phosphates,  and  he  obtained  in  direct  determinations 
such  an  irregularity  in  the  results  and  such  a  great  variation  from  the  theo- 
retically calculated  quantity  of  hydrochloric  acid  that  he  considers  this 
method  as  unserviceable. 

The  objections  made  to  Morner  and  Sjoqvist's  method  are  in  part 
unimportant  and  part  incorrect  and  unfounded  (Sjoqvist'),  and  for  the 
present  we  have  no  better  method  or  one  yielding  more  trustworthy  results. 

In  testing  for  volatile  fdtty  acids  the  contents  of  the  stomach  should  not 
be  directly  distilled,  as  volatile  fatty  acids  may  be  formed  by  the  decom- 
position of  other  bodies,  such  as  proteid  and  lia3moglobiu.  The  neutralized 
contents  of  the  stomach  are  therefore  precipitated  with  alcohol  at  ordinary 
temperature,  filtered  quickly,  pressed,  and  repeatedly  extracted  with  alco- 
hol. The  alcoholic  extracts  are  made  faintly  alkaline  by  soda,  and  the 
alcohol  distilled.  The  residue  is  now  acidified  by  sulphuric  or  phosphoric 
acid  and  distilled.  The  distillate  is  neutralized  by  soda  and  evaporated  to 
dryness  on  the  water-bath.  The  residue  is  extracted  with  absolute  alcohol, 
filtered,  the  alcohol  distilled  off,  and  this  residue  dissolved  in  a  little  water. 
This  solution  may  be  directly  tested  for  acetic  acid  with  sulphuric  acid  and 
alcohol  or  with  ferric  chloride.  Formic  acid  may  be  tested  for  by  silver 
nitrate,  which  quickly  gives  a  black  precipitate;  and  butyric  acid  is  detected 
by  the  odor  after  the  addition  of  an  acid.  In  regard  to  the  methods  for 
more  fully  investigating  the  different  volatile  fatty  acids,  the  reader  ia 
referred  to  other  text-books. 


III.  The  Glaiid.s  of  the  Mucous  Membrane  of  the 
Intestine  and  their  Secretions. 

The  Secretion  of  Brunner's  Glands.  These  glands  are  partly  considered 
as  small  pancreas-glands  and  partly  as  mucous  or  salivary  glands.  Their 
importance  in  various  animals  is  different.  According  to  Grutzner* 
they  are  closely  related  in  dogs  to  the  pyloric  glands  and  contain  pepsin. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 
«  Zeitschr.  f.  klin.  Med.,  Bd.  33. 
»iW(Z..  Bd.  32. 
♦PflUeei's  Arch..  Bd.  12. 


280  DIOESTIOJS. 

The  views  in  regard  to  the  occurrence  of  a  diastatic  enzyme  are  contradic- 
tory, and  the  difficulty  of  collecting  the  secretion  from  these  glands  free 
from  contamination  makes  this  assumption  somewhat  unreliable. 

The  Secretion  of  Lieberkuhn's  Glands.  The  secretion  of  these  glands 
has  been  studied  by  the  aid  of  a  fistula  in  the  intestine  according  to  the 
method  of  Thikt  and  Vella.  Very  little  if  any  secretion  takes  place  in 
fasting  animals  (dog)  when  the  mucous  membrane  is  not  irritated.  In 
lambs  Pregl  found  the  secretion  continuous.  The  partaking  of  food 
causes  a  secretion,  and  in  lambs  increases  the  secretion  already  taking  place. 
Mechanical,  chemical,  and  electrical  irritations  act  in  the  same  manner  in 
dogs  (Thiry).  Pilocarpin  does  not  increase  the  secretion  in  lambs,  and  in 
dogs  it  does  not  seem  to  be  always  active  (Gamgee  ').  Tlie  quantity  of  this 
secretion  in  the  course  of  24  hours  has  not  been  exactly  determined. 

In  the  upper  part  of  the  small  intestine  of  the  dog  this  secretion  is 
scanty,  slimy,  and  gelatinous;  in  the  lower  part  ifc  is  more  fluid,  with 
gelatinous  lumps  or  flakes  (Eohmann).  Intestinal  juice  has  a  strong 
alkaline  reaction,  generates  carbon  dioxide  on  the  addition  of  an  acid,  and 
contains  (in  dogs)  nearly  a  constant  quantity  of  NaOl  and  NajCO,,  4.8-5 
and  4-5  p.  m.  respectively  (Gumilewski,  Eohmann").  It  contains 
proteid  (Thiey  found  8.01  p.  m.),  the  quantity  decreasing  with  the  dura- 
tion of  the  elimination.  The  quantity  of  solids  varies.  In  dogs  the 
ijuantity  of  solids  is  12.2-24.1  p.  m.,  and  in  lambs  29.85  p.  m.  The 
specific  gravity  of  the  intestinal  juice  of  the  dog,  according  to  the  observa- 
tions of  Thiry,  is  1.010-1.0107,  and  in  lambs  1.01427  (Pregl).  The 
intestinal  juice  from  lambs  contains  18.097  p.  m.  proteid,  1.274  p.  m. 
albumoses  and  mucin,  2.29  p,  m.  urea,  and  3.13  p.  m.  remaining  organic 
bodies. 

The  action  of  the  intestinal  juice  has  been  studied  by  many  investi- 
gators, but  the  views  concerning  it  are  at  variance.  According  to 
certain  experimenters  it  has  the  power  of  converting  boiled  starch  into 
sugar,  but  others  claim  that  it  has  not  the  property.  Still  this  action  is 
always  only  slight.  However,  it  seems  generally  accepted,  as  shown  by 
Paschutin,  Browk"  and  Heron,  Bastianelli,'  and  others,  that  the 
intestinal  juice  or  an  infusion  of  the  mucous  membrane  has  an  inverting 
action  on  cane-sugar  or  maltose.  Lactose  seems,  at  least  in  certain  animals, 
as  dog  and  calf  (PiOHMAXX  and  Lappe)  and  new-born  children  (Pautz  and 

'  Thiry,  Wieti.  Sitzungsber.,  Bd.  50  ;  Vellsi,  Molescbott's  Untersuch.,  Bd.  13;  Pregl, 
PflUger's  Arch.,  Bd.  61  ;  Gamgee,  Physiol.  Chem.,  Vol.  2,  p.  410,  where  Vella  and 
Masloff  ;iie  quoted 

'  Gumilewski.  Pflijger's  Arch.,   Bd.  '59  ;  Roiunann,  ibid.,  Bd.  41. 

*  Paschutin,  Centralbl.  f.  d.  ined.  Wissensch.,  1870,  S.  501  ;  Brown  and  Heron, 
Annal.  d.  Chem.  u.  Pharm.,  Bd.  204  ;  Bastiauelli,  Molescbott's  Untersuch.  zur  Natur* 
lehre,  Bd.  14.     This  contains  all  the  older  literature. 


INTESTIAAL  JUICE.  281 

Vogel'),  to  be  inverted  by  a  special  enzyme,  lactase.  The  action  on 
curboliytlrates  takes  ])laco  more  quickly  and  to  a  greater  extent  in  tlie  up})er 
part  of  the  intestine,  and  correspondingly  tiie  absorption  of  starch  and 
sugar  occurs  more  quickly  in  the  upper  j)art  than  in  the  lower  section  of  the 
intestine  (Lannois  and  Lkimnk,"  Kuhmanis'). 

\\y  experiments  with  chloroform-water  extracts  of  the  mucosa  of  the 
small  intestine,  as  well  as  with  the  precipitates  obtained  on  the  addition  of 
alcohol  to  these  extracts,  KuuGKii^  has  confirmed  the  view  that  the  in- 
testinal mucosa  does  not  contain  either  a  proteolytic  or  steatolytic  but 
only  an  amylolytic  and  inverting  enzyme. 

Intestinal  juice  does  not  split  neutral  fats,  but  it  has  the  property,  like 
other  alkaline  fluids,  of  emulsifyiiuj  the  fats.  In  regard  to  its  action  on 
albuminous  bodies  most  investigators  agree  that  the  intestinal  juice  has  no 
action  on  boiled  proteid  or  meat,  while  it  dissolves  fibrin  according  to 
Thiry.  Albumoses  are  not  converted  into  peptones  (Wenz*).  Contrary 
to  other  investigators,  Sciiiff  claims  that  the  juice  from  a  successful  fistula 
operation  digests  not  only  coagulated  proteid  and  lumps  of  casein,  but  ;.lso 
unboiled  and  boiled  meat;  attention  should,  however,  be  called  to  the  fact 
that  the  action  of  micro-organisms  was  not  excluded  in  these  experiments. 
According  to  Gachet  and  Paciion  '  a  digestion  of  coagulated  white  of 
egg  can  take  place  in  the  duodenum  on  eliminating  the  gastric  and 
pancreatic  juices. 

Human  intestinal  juice  in  a  case  of  anus  ^jrcBternafuralis  has  been  inves- 
tigated by  Demant.  This  juice  showed  itself  entirely  inactive  on  albumi- 
nous bodies,  even  on  fibrin  and  on  fats.  It  had  only  a  very  faint  action  on 
boiled  starch.  Tukby  and  Manning  '  have  investigated  human  intestinal 
juice.  The  specific  gravity  was  on  an  average  1.00G9.  The  reaction  was 
alkaline,  and  an  abundant  development  of  carbon  dioxide  took  place  on 
adding  acid.  Proteids  were  not  digested;  starch  was  first  saccharified  very 
slowly,  while  cane-sugar  and  maltose  were  inverted  by  the  juice.  Fats  were 
both  emulsified  and  saponified.  These  experiments  on  the  action  of  the 
intestinal  juice  onfood  introduced  into  the  intestine  in  casesof  isolated  loop 
of  the  intestine  in  animals,  and  in  human  intestine  in  cases  of  amis 
pneiernatnralis,  have  not  given  any  positive  results,  because  of  the  putre- 
faction 2:)roces9es  going  on  in  the  intestine. 

'  R51imauu  aud  Lappe,  Ber.  d.  deutscb.  chem.  Gesellsch.,  Bd.  28;  Pautz  and  Vogel, 
Zeitschr.  f.  Biologic,  Bd.  32. 

'  Arch.  d.  Physiol,  (o).  Tome  1. 
3  Zeitschr.  f.  Biologio,  Bd.  37. 

*  Zeitschr.  f.  Biologic.  Bd.  22,  which  also  contains  the  older  literature. 

"  Schiff,  Ccntiulbl.  f.  d.  nied.  "Wisscnsch.,  1868,  S.  357  ;  Gachet  and  Pachon,  Arch, 
de  Physiol.  (5),  Tome  10. 

*  Dcmaut,  Virchow's  Arch.,  Bd.  75;  Turby  and  Manning,  Guy's  Hospital  Report. 
Vol.  48,  p.  277  ;  also  Ceulralbl.  f.  d.  med.  Wissensch.,  1892,  S.  945. 


2S2  DIGESTION. 

The  secretion  of  the  glands  in  the  large  intestine  seems  to  consist  chiefly 
of  mucus.  Fistulas  have  also  been  introduced  into  these  parts  of  the 
intestine,  which  are  chiefly  if  not  entirely  to  be  considered  as  absorption 
organs.  The  investigations  on  the  action  of  this  secretion  on  nutritive 
bodies  have  not  as  yet  yielded  any  positive  results. 

IV.  Pancreas  and  Pancreatic  Jviice. 

In  invertebrates,  which  have  no  pepsin  digestion  and  which  also  have 
no  formation  of  bile,  the  pancreas,  or  at  least  an  analogous  organ,  seems  to 
be  the  essential  digestion  gland.  On  the  contrary,  an  anatomically  charac- 
teristic pancreas  is  absent  in  certain  vertebrates  and  in  certain  fishes. 
Those  functions  which  should  be  performed  by  this  organ  seem  to  be  per- 
formed in  these  animals  by  the  liver,  which  may  be  rightly  called  hepato- 
PANCREAS.  In  man  and  in  most  vertebrates  the  formation  of  bile  and  of 
certain  secretions  containing  enzymes  important  for  digestion  is  divided 
between  the  two  organs,  the  liver  and  the  pancreas. 

The  pancreas  gland  is  similar  in  certain  respects  to  the  parotid  gland. 
The  secreting  elements  of  the  former  consist  of  nucleated  cells  whose  basis 
forms  a  mass  rich  in  proteids,  which  expand  in  water  and  in  which  two 
distinct  zones  exist.  The  outer  zone  is  more  homogeneous,  the  inner  cloudy, 
due  to  a  quantity  of  granules.  The  nucleus  lies  about  midway  between  the 
two  zones,  but  this  position  may  change  with  the  varying  relative  size  of 
the  two  zones.  According  to  Heidenhaii^  '  the  inner  part  of  the  cells 
diminishes  in  size  during  the  first  stages  of  digestion,  in  which  the  secretion 
is  active,  while  at  the  same  time  the  outer  zone  enlarges  owing  to  the 
absorption  of  new  material.  In  a  later  stage,  when  the  secretion  has 
decreased  and  the  absorption  of  the  nutritive  bodies  has  taken  place,  the 
inner  zone  enlarges  at  the  expense  of  the  outer,  the  substance  of  the  latter 
having  been  converted  into  that  of  the  former.  Under  physiological  con- 
ditions the  glandular  cells  are  undergoing  a  constant  change,  at  one  time 
consuming  from  the  inner  part  and  at  another  time  growing  from  the  outer 
part.  The  inner  granular  zone  is  converted  into  the  secretion,  and  the 
outer,  more  homogeneous  zone,  which  contains  the  repairing  material,  is 
then  converted  into  the  granular  substance. 

Besides  considerable  quantities  of  proteids,  globulin,  niLcleo-proteid  (see 
Chapter  II),  and  albumin,  we  find  in  this  gland  several  enzymes,  or,  more 
correctly,  zymogens,  which  will  be  described  later.  We  also  find  in  this 
gland  nuclein,  leucin  (butalanin),  tyrosin  (not  in  the  perfectly  fresh  gland), 
xanthin,  1-8  p.  m.,  hypoxanthin,  3-4  p.  m.,  guanin,  2-7.5  p.  m.  (all 
figures  are  calculated  for  the  dried  substance,  Kossel"),  adenin,  inosity 

1  PflUiger's  Arch.,  Bd.  10. 

"  Zeitschr.  f.  physiol.  Chem.,  Bd.  8. 


PAM'liEATIC  JUICE.  283 

lactic  acid.,  volatile  fattij  aciiL^,  f<^ts,  and  mineral  svhstances.  According 
to  the  investii^'iitioiis  of  Oidtmann'  the  human  pancreas  contains  745.3 
p.  ni.  water,  245.7  p.  m.  organic  and  9.5  p.  m.  inorganic  snbstances. 

liesides  the  already-mentioned  (Chapter  WW)  relationsliip  to  the  trans- 
formation of  sugar  in  tlie  animal  body,  the  pancreas  has  the  property  of 
secreting  a  juice  especially  important  in  digestion. 

Pancreatic  Juice.  This  secretion  may  be  obtained  by  adjusting  a  fistula 
in  the  excretory  duet,  according  to  tlie  metliods  suggested  by  IjKKXAKD, 
LuDWiG,  and  IIeidenhain,  and  perfected  by  Pawlow."  If  the  operation 
is  performed  with  suflficient  rapidity  and  under  favorable  conditions  a  power- 
fully active  secretion  maybe  obtained  either  immediately  after  the  operation 
{temporary  fistula)  or  after  some  time  {permanent  fistula). 

In  herbivora,  such  as  rabbits,  whose  digestion  is  uninterrupted,  the 
secretion  of  the  pancreatic  juice  is  continuous.  In  carnivora  it  seems,  on 
the  contrary,  to  be  intermittent  and  dependent  on  the  digestion.  During 
starvation  tiie  secretion  almost  stops,  but  commences  again  after  partaking 
of  food.  Food  seems  to  act  in  a  twofold  manner.  First,  it  may,  with  the 
more  abundant  flow  of  blood  during  the  digestion,  which  is  seen  by  the  red 
color  of  the  gland,  convey  a  larger  quantity  of  nutritive  material  to  the 
gland,  and  thereby  cause  the  secretion  of  a  juice  rich  in  solids.  In  another 
way  the  food  may  also,  by  the  irritation  which  it  produces  on  the  mucous 
coat  of  the  stomach  and  the  duodenum,  indirectly  cause  an  increased  secre- 
tion. 

According  to  the  observations  of  Bernstein,  Heidenhain,  and  others, 
the  secretion  increases  rapidly  after  eating,  and  it  reaches  its  maximum  in 
the  course  of  the  first  three  hours.  From  this  time  the  secretion  diminishes, 
but  may  again  increase  from  the  5th-7th  hour,  when  generally  large  quan- 
tities of  food  pass  from  the  stomach  to  the  intestine.  Then  it  again 
decreases  continuously  from  the  9tli-llth  hour,  and  stops  entirely  at  the 
15th-16th  hour. 

The  specific  irritants  for  the  secretion  of  pancreatic  juice  are,  according 
to  Pawlow  and  his  colaborators,  acids  of  various  kinds,  hydrochloric  acid 
as  well  as  lactic  acid,  and  fats.  Alkalies  and  alkali  carbonates  have  on  the 
contrary  a  retarding  action.  It  seems  as  if  the  acids  act  in  a  reflex 
manner  by  irritating  the  mucosa  of  the  duodenum.  The  water,  which 
causes  a  secretion  of  acid  gastric  juice,  also  becomes  an  irritant  for  the 
pancreatic  secretion,  but  may  also  be  an  independent  exciter.  The  psychical 
moment  may,  at  least  in  the  first  place,  have  an  indirect  action  (secretion 

'  Cited  from  v.  Gonip-Bosanez,  Lchrbucb,  4.  Aiifl. .  S.  732. 

*  Bernard.  Lemons  de  Physiol.,  Tome  2,  p.  190;  Ludwig,  see  Bernstein,  Arbeiten  a. 
d.  physiol.  Anstalt  zu  Leipzig,  1869;  Heidenbain,  PHiiger's  Arch.,  Bd.  10,  S.  604  : 
Pawlow,  Die  Arbeit  der  Verdauungsdrusen,  Wiesbaden,  1898. 


284  BIG  ES  TWA'. 

of  acid  gastric  jaice),  aud  the  food  seems  likewise  to  liave  an  action  on 
])aiicreatic  secretion  by  its  action  on  the  secretion  of  gastric  juice.  The 
quality  of  the  food  has,  on  the  contrary,  an  nnmistakable  influence  on  the 
composition  of  the  juice  and  the  quantity  of  the  different  enzymes.  Thus, 
the  juice  is  richest  in  diastatic  enzyme  after  bread  diet,  and  richest  in  the 
steotolytic  enzyme  after  milk  food.  When  a  dog  passes  from  a  milk-and- 
l)read  diet  to  an  exclnsive  meat  diet  the  juice  becomes  richer  in  proteolytic 
enzyme  and  jioorer  in  diastatic  enzyme.  According  to  Gottlieb  irritating 
bodies,  as  mustard-oil,  cause  an  increased  secretion  of  pancreatic  inice. 
According  to  Pawlow  and  Schieokikh  '  his  experiment  is  not  conclusive 
on  account  of  the  great  intensity  of  the  irritant  used  by  him. 

As  to  the  quantity  of  pancreatic  juice  secreted  in  the  24  hours  authorities 
differ.  According  to  the  determinations  of  Pawlow  and  his  collaborators, 
KuwscHiNSKi,  Wassiliew  and  Jablonskt,'  the  average  quantity  (with 
normally  acting  jaice)  from  a  permanent  fistula  in  dogs  is  21.8  c.c.  per 
kilo  in  the  24  hours. 

The  pancreatic  juice  of  the  dog  is  a  clear,  colorless,  and  odorless 
alkaline  fluid  which  when  obtained  from  a  temporary  fistula  is  very  rich  in 
proteids,  sometimes  so  rich  that  it  coagulates  like  the  white  of  the  egg 
on  heating.  Besides  proteids  the  juice  contains  also  three  long-known 
enzymes — one  diastatic,  one  fat-splitting,  and  one  which  dissolves  proteids. 
The  last-mentioned  has  been  called  trypsin  by  Kuhne.  Besides  this 
KuHXE  and  later  investigators  have  found  a  rennin-like  enzyme  in  the 
gland  as  well  as  the  juice.  Besides  the  above-mentioned  bodies  the 
pancreatic  juice  habitually  contains  small  quantities  of  leucin,  fat,  and 
snaps.  As  mineral  constituents  it  contains  chiefly  alkali  chlorides  and  con- 
siderable alkali  carbonate,  some  phosphoric  acid,  lime,  magnesia,  and  iron. 

The  older  analyses  of  the  juice  from  a  permanent  fistula  by  C,  Schmidt 
are  the  results  of  a  more  or  less  abnormal  juice,  hence  we  shall  give  only  the 
analyses  of  juices  from  temporary  fistulas  on  dogs.'  The  results  are  given 
in  parts  per  1000. 

a.  b. 

Water 900.8  884.4 

Solids 99.2  115.6 

Organic  substance 90.4  

Ash 8.8  

The  mineral  constituents  consisted  cliiefly  of  NnCl,  7.4  p.  m. 

lu  the  paiicienlic  juice  of  rabbits  11-26  p  ni.  solids  have  been  found,  jind  in  that 
from  sheep  14  3-: SO  9  p.  ni.  In  the  pan(;reatic  juice  of  the  horse  9-15.5  p.  ni.  solids  have 
been  found  ;  in  that  of  the  pigeon,  12-14  p.  m. 

'Gottlieb,  Arch.  f.  exp.  Path.  w.  Pharm.,  Bd.  33;  Schirokikh,  Arch,  des  scienc. 
biol.  de  St.  Petersbourg,  Tome  3,  p.  449. 

"^  Ibid.,  Tome  2,  p.  391.  The  older  statements  of  Keferstein  and  Hallwachs,  Bidder 
and  Schmidt,  and  others  may  be  found  in  Kiihne,  Lehrbuch,  p.  114. 

=•  Cited  from  Maly  in  Hermann's  Ilaiidbuch  der  Physiol.,  Bd.  5,  Theil  2,  S.  189. 


AMYLOrSIN  AAD   ST  K APS  J  N.  285 

The  human  pancreatic  jiiifc  has  been  analyzod  l)v  IIkiitkk  '  in  a  case  f)f  stoppage  of 
the  f.\it  of  tiie  juice  by  the  pressure  of  a  cancer.  This  juice,  wliich  cr>ul(i  haidly  be  con- 
sidered as  normal,  was  cleai',  alliaiiue,  without  odor,  and  contained  the  three  enzymes. 
It  contained  peptone,  l)ut  no  other  proleid.  Tin- (piantiiy  of  solids  was  24. 1  p.  m.  Of 
these  G.4  p.  m.  were  sohible  in  alcohol.  It  contaiiiL-d  11. r>  ]>.  m.  peptone  (and  enzvmes) 
and  (>.2  p.  m.  mineral  substances.  Zawadsky' has  analyzed  the  pancreatic  juice  of  a 
young  woman  with  a  fistula,  and  found  864.05  p.  m.  water,  132  51  p.  m.  organic  and 
8.44  p.  m.  inorganic  substances.     The  quantity  of  protein  bodies  was  93.05  p.  m. 

Among  tlie"  constittients  of  the  pancreatic  jnice,  the  three  enzymes  are 
the  most  important. 

Amylopsin  or  pancreatic  diastase,  which,  according  to  Korowix  and 
ZwKiFHL,-'  is  not  fonnd  in  new-born  infants  and  does  not  appear  until  more 
than  one  month  after  birth,  seems,  although  not  identical  with  jityalin,  to 
be  nearly  related  to  it.  Amylopsin  acts  very  energetically  upon  boiled 
starcli,  and  according  to  Kuhne^  upon  unboiled  starch,  especially  at  +  'M^ 
to  40°  C,  and,  similar  to  the  action  of  saliva,  forms,  besides  dextrin,  chiefly 
isomaltose  and  maltose,  with  only  very  little  dextrose  (Musculus  and 
V.  Merixo,  Kulz  and  Vogel*).  The  dextrose  is  probably  formed  by  the 
action  of  the  invertin  '  existing  in  the  gland  and  juice. 

If  the  natural  pancreatic  juice  is  not  to  be  obtained,  then  the  gland, 
best  after  it  has  been  exposed  a  certain  time  ('i-i  hours)  to  the  air,  may  be 
treated  with  water  or  glycerin.  This  infusion  or  the  glycerin  extract 
diluted  with  water  (when  a  glycerin  has  been  used  which  has  no  reducing 
action)  may  be  tested  directly  with  starch-paste.  It  is  safer,  however,  to 
first  precipitate  the  enzyme  from  the  glycerin  extract  by  alcohol,  and  wasli 
with  this  liquid,  dry  the  precipitate  over  sulphuric  acid,  and  extract  with 
■water.  The  enzyme  is  dissolved  by  the  water.  The  detection  of  sugar 
may  be  done  in  the  same  manner  as  in  the  saliva. 

Steapsin  or  Fat-splittirg  Enzyme.  The  action  of  the  pancreatic  juice 
on  fats  is  twofold.  Firtt,  the  neutral  fats  are  split  into  fatty  acids  and 
glycerin,  which  is  an  enzymotic  process;  and  secondly,  it  has  also  the 
property  of  emulsifying  the  fats. 

The  action  of  the  pancreatic  juice  in  splitting  the  fats  may  be  shown  in 
the  following  way:  Shake  olive-oil  with  caustic  soda  and  ether,  siphon  off 
the  ether  and  filter  if  necessary,  then  shake  the  ether  repeatedly  with  water 
and  evaporate  at  a  gentle  heat.  In  this  way  we  obtain  a  residue  of  fat  free 
from  fatty  acids  which  is  neutral,  and  which  dissolves  in  acid-free  alcohol 
and  is  not  colored  red  by  alkanet  tincture.  If  such  fat  is  mixed  with 
perfectly  fresh  alkaline  pancreatic  juice  or  with  a  freshly  prepared  infnsiou 
of  the  fresh  gland  and  treated  with  a  little  alkali  or  with  a  faintly  alkaline 
glycerin  extract  of  the  fresh  gland  (9  parts  glycerin  and  1  part  1^  soda 

'  Ilericr,  Zeitsclir.  f.  physiol.  Chem.,  B\l.  4;  Zawadsky,  Centralbl.  f.  Physiol.,  Bd. 
5,  S.  179. 

'  Korowin,  Maly's  Jahresber. ,  Bd.  3;  Zweifel,  foot-note  5,  page  252. 
»Lehrbuch.  S.  117. 

*  See  foot-note  4,  page  253. 

*  See  Tebb,  Journal  of  Physiol.,  Vol.  IT),  and  Abelous,  C.  R.  Soc.  de  bid.,  1891. 


286  DIGESTION. 

solution  for  each  gramme  of  the  gland),  and  some  litmns  tincture  added 
au.i  tlie  mixtare  warmed  to  +  37"  C,  the  alkaline  reaction  will  gradually 
disappear  and  an  acid  one  take  its  place.  This  acid  reaction  depends  upon 
the  conversion  of  the  neutral  fats  by  the  enzyme  into  glycerin  and  free  fatty 
acids. 

The  splittiug  of  the  neutral  fats  may  also  be  shown  more  exactly  by  the 
following  method:  The  mixture  of  neutral  fats  (absolutely  free  from  fatty 
acids)  and  pancreatic  juice  or  pancreas  infusion  is  digested  at  the  tempera- 
ture of  the  body  and  treated  with  some  soda  and  repeatedly  shaken  with 
fresh  quantities  of  ether  until  all  the  unsplit  neutral  fats  are  removed. 
Then  it  is  made  acid  with  sulphuric  acid,  after  which  shake  the  acid  liquid 
with  ether,  evaporate  the  ether,  and  test  the  residue  for  fatty  acids. 

Another  simple  process  for  the  demonstration  of  the  fat-splitting  action 
of  the  pancreas-glands  is  the  following  (Cl.  Berkaed):  A  small  portion  of 
the  perfectly  fresh,  finely  divided  gland  substance  is  first  soaked  in  alcohol 
(of  90^).  Then  the  alcohol  is  removed  as  far  as  possible  by  pressing 
between  blotting-paper,  after  which  the  pieces  of  gland  are  covered  with  an 
ethereal  solution  of  neutral  butter-fat  (which  may  be  obtained  by  shaking 
milk  with  caustic  soda  and  ether).  After  the  evaporation  of  the  etlier  the 
pieces  of  gland  covered  with  butter-fat  are  pressed  between  two  Avatch- 
glasses  and  then  gently  heated  to  37°  to  40°  C.  in  this  position.  After  a 
certain  time  a  marked  odor  of  butyric  acid  appears. 

The  action  of  the  pancreatic  juice  in  splitting  fats  is  a  process  analogous 
to  that'of  saponification,  the  neutral  fats  being  decomposed,  by  the  addition 
of  the  elements  of  water,  into  fatty  acids  and  glycerin  according  to 
the  following  formula:  C^H^.O^.E,  (neutral  fat)  +  3H,0  =  C3H,.03.H3 
(glycerin)  +  3(H.0.R)  (fatty  acid).  This  depends  upon  a  hydrolytic 
splitting,  which  was  first  positively  proved  by  Bernard  and  Berthelot.' 
The  pancreas-enzyme  also  decomposes  other  esters  just  as  it  does  the  neutral 
fats  (Nencki,  Baas^).  The  pancreas-enzyme  which  decomposes  fats  has 
been  less  studied  than  the  other  pancreas-enzymes,  and  it  has  indeed  been 
questioned  whether  or  not  the  decomposition  of  the  neutral  fats  in  the 
intestine  may  not  be  effected  through  lower  organisms.  According  to  the 
investigations  of  Nexcki  it  seems  that  the  pancreas  actually  contains  an 
enzyme  which  decomposes  fats.  This  enzyme,  which  is  still  little  known, 
appears  to  be  very  sensitive  to.  acids,  and  it  is  often  absent  in  acid  glands 
not  perfectly  fresh.  If  a  watery  infusion  of  the  gland  prepared  cold  be 
treated  with  calcined  magnesia,  then  the  enzyme  in  question  will,  according 
to  Danilewski,'  be  retained  by  the  magnesia  j^recipitate. 

The  fatty  acids  which  are  split  off  by  the  action  of  the  pancreatic  juice 
combine  in  the  intestine  with  the  alkalies,  forming  soaps  which  have  a 

'Bernard,  Ann.  de  cbim.  et  physique  (3  ser.).  Tome  25;  Berthelot,  Jahresber.  d. 
Chem..  1«55,  S.  733. 

'  Nencki,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  20  ;  Baas,  Zeitschr.  f.  physiol.  Chem.,^ 
Bd.  14.  S.  416. 

*  Vircbow's  Arch.,  Bd.  25. 


TRYPSIN.  287 

strong  emnlsifying  action  on  tlie  fats,  and  tlms  the  pancreatic  juice  bocomea 
of  great  importance  in  the  einulsification  and  tlie  al>sorption  of  the  fats. 

In  digestion  experiments  with  the  pancreas-gland  or  the  watery  extract 
of  the  same,  Klug  '  has  observed  a  development  of  gases,  carbon  dioxide  and 
also  liydrogen,  whicli  were  not  produced  by  putrefaction  and  which  he  con 
eiders  are  produced  by  an  enzymotic  cleavage  of  the  fats. 

Trypsin.  The  action  of  the  pancreatic  juice  in  digesting  proteids  was 
first  observed  by  Bernaku,  but  first  proved  by  Cokvisaut."  It  depends 
upon  a  special  enzyme  called  by  Kuiine  trypsin.  Strictly  speaking,  this 
enzyme  does  not  occur  in  the  gland  itself.  In  the  gland,  more  probably,  a 
zymogen  occurs  from  whicli  the  enzyme  is  split  off  or  formed  during  secre- 
tion, also  by  the  action  of  water,  acids,  alcohol,  and  other  substances. 
According  to  Albertoni,'  this  zymogen  is  found  in  the  gland  in  the  last 
third  of  the  intra-uterine  life.  Enzymes  similar  to  trypsin  occur  also  in  the 
plant  kingdom. 

The  purest  trypsin  thus  far  prepared,  isolated  by  Kuhne,*  is  soluble  in 
water,  but  insoluble  in  alcohol  or  glycerin.  The  less  pure  enzyme,  on  the 
contrary,  is  soluble  in  glycerin.  If  the  solution  of  the  enzyme  in  water  is 
heated  to  the  boiling-point  with  the  addition  of  a  little  acid,  it  decomposes 
into  coagulated  proteid  and  peptone  (Kuiine).  According  to  the  investi- 
gations of  liiERSTACKi '  i')ure  trypsin  in  0.25-0.5^'^  soda  solution  is  destroyed 
in  5  minutes  by  heating  to  50°  C.  It  is  destroyed  by  heating  its  neutral 
solution  to  45°  C.  The  i:>resence  of  albumoses  or  certain  ammonium  salts 
in  alkaline  trypsin  solutions  has  a  protective  action  to  a  certain  extent. 
Trypsin  is  destroyed  by  gastric  juice.  Like  other  enzymes,  trypsin  is 
characterized  by  its  physiological  action.  This  action  consists  in  dissolving 
proteids  and  especially  fibrin  in  alkaline,  neutral,  or  even  faintly  acid  solu- 
tions with  readiness. 

The  preparation  of  pure  trypsin  has  been  tried  by  various  experimenters. 
The  purest  seems  to  have  been  prepared  according  to  the  rather  complicated 
method  of  Kuhne.'  In  studying  the  action  of  trypsin  a  less  pure  prepara- 
tion may  often  answer,  and  various  methods  of  preparing  such  have  been 
proposed,  but  Ave  cannot  describe  all  of  them.  For  the  production  of  a 
glycerin  extract  (IIeidenhain  ')  the  gland  should  be  rubbed  with  glass 
powder  or  pure  quartz-sand,  this  mass  carefully  mixed  with  acetic  acid  of 
Ifo  (1  c.c.  to  each  grm.  of  gland),  then  for  each  part  of  the  gland-mass  add 

>  Pfliiger's  Arch.,  Bd.  70. 

'  Gaz.  hebdomadnire,  1857,  Nos.  15,  16,  19.  Cited  from  Bunge,  Lelul)uch,  4.  Aufl,, 
8.  135. 

»  See  Maly's  Jahresber.,  Bd.  8,  S.  254. 

*  Verb.  d.  naturb.-med.  Vereius  zu  Heidelberg  (N.  F.),  Bd.  1,  Heft  3. 
"  Zeitschr.  f.  Biologic,  Bd.  28. 

*  Verb.  d.  naturb.-med.  Vereins  zu  Heidelberg  (N.  F.),  Bd.  1,  Heft  3. 
'  Pfluger's  Arcii.,  Bd.  10. 


288  DIGESTION. 

10  parts  of  glycerin,  and  filter  after  about  three  days.  By  precipitating  the 
glycerin  extract  with  alcohol  and  redissolving  the  precipitate  in  water,  we 
obtain  a  solution  which  has  a  powerful  digestive  action.  A  watery  infusion 
of  the  gland  may  be  made  only  after  it  has  been  exposed  to  the  air  for  24 
hours,  and  5-10  parts  of  water  for  each  part  by  weight  of  the  gland  should 
be  used.  According  to  Kuhne  '  the  impure  trypsin  is  allowed  to  undergo 
aatodigestion  in  a  0.2^  soda  solution  and  in  the  presence  of  thymol.  After 
the  conv^ersion  of  the  albumoses  into  peptones  the  trypsin  may  be  precipi- 
tated by  ammonium  sulphate.  An  active  but  impure  infusion  may  be 
obtained  by  digesting  the  finely  divided  gland  for  a  few  days  with  water 
containing  5-10  c.c.  chloroform  per  liter  (Salkowski). 

The  action  of  tryijsin  on  proteids  is  best  demonstrated  by  the  use  of 
fibrin.  Very  considerable  quantities  of  this  albuminous  body  are  dissolved 
by  a  small  amount  of  trypsin  at  37-40°  C.  It  is  always  necessary  to  make 
a  control  test  with  fibrin  alone,  with  or  without  the  addition  of  alkali. 
Fibrin  is  dissolved  by  trypsin  without  any  putrefaction;  the  liquid  has  a 
pleasant  odor  somewhat  like  bouillon.  To  completely  exclude  putrefaction 
a  little  thymol,  chloroform,  or  ether  should  be  added  to  the  liquid.  Trypsin 
digestion  differs  essentially  from  pepsin  digestion  iu  that  the  first  takes 
place  in  neutral  or  alkaline  reaction  and  not,  as  is  necessary  for  pepsin 
digestion,  in  an  acidity  of  1-2  p.  m.  HCl,  and  further  by  the  fact  that  the 
proteids  dissolve  in  trypsin  digestion  without  previously  swelling  up. 

As  trypsin  not  only  dissolves  proteids  but  also  other  protein  substances, 
such  as  gelatin,  this  body  may  be  used  in  detecting  trypsin.  The  liquefac- 
tion of  a  strongly  disinfected  gelatin  is,  according  to  Fermi, ^  a  very  delicate 
reagent  for  trypsin  or  tryptic  enzyme. 

Many  circumstances  exert  a  marked  influence  on  the  rapidity  of  the 
trypsin  digestion.  With  an  increase  in  the  quantity  of  enzyme  present  the 
digestion  is  hastened  at  least  to  a  certain  point,  and  the  same  is  also  true  of 
an  increase  in  temperature  at  least  to  about  +  40°  C,  at  which  temperature 
the  proteid  is  very  rapidly  dissolved  by  the  trypsin.  The  reaction  is  also  of 
the  greatest  importance.  Trypsin  acts  energetically  in  neutral,  or  still 
better  in  alkaline,  solutions,  and  best  in  an  alkalinity  of  3-4  p.  m.  Na^COj. 
Free  mineral  acids,  even  in  very  small  quantities,  completely  prevent  the 
digestion.  If  the  acid  is  not  actually  free,  but  combined  with  albuminous 
bodies,  then  the  digestion  may  take  place  quickly  when  the  acid  combina- 
tion is  not  in  too  great  excess  (Chittenden"  and  Cummins').  Organic 
acids  act  less  disturbingly,  and  in  the  presence  of  0.2  p.  m.  lactic  acid  and 
the  simultaneous  presence  of  bile  and  common  salt  the  digestion  may  indeed 
proceed  more  quickly  than  in  a  faintly  alkaline  liquid  (Lindberger).     The 

'  Centralbl.  f.  d.  med.  Wissensch.,  1886,  S.  629. 

*  Arch.  f.  Hygieue,  Bd.  12. 

*  Studies  from  the  Pbysiol.  Cbem.  Laboratory  of  Yale  College,  New  Haven,  1885, 
Vol.  1,  p.  100. 


PRODUCTS  OFTIiYPi<IN  DIGESTION.  289 

■statement  of  Raciifoud  and  Sol'thoate  that  tlie  bile  can  prevent  the 
injurious  action  of  tl)e  hydrochloric  acid,  and  that  a  mixture  of  pancreatic 
juice,  bile,  and  hydrochloric  acid  digests  better  than  any  other  mixture  of 
pancreatic  juice,  could  not  be  substantiated  by  Chittenden  and  Albro.' 
Carbon  dioxide,  according  to  Schiehbeck,'  has  a  retarding  action  in  acid 
solutions,  but  it  accelerates  the  tryptic  digestion  in  faintly  alkaline  liquids. 
ForcUjn  bo(Ues,"&ach  as  borax  and  potassium  cyanide,  may  promote  tryptic 
digestion,  while  other  bodies,  such  as  salts  of  mercury,  iron,  and  others 
(Chittenden  and  Cummins),  or  salicylic  acid  in  large  quantities,  may  have 
a  preventive  action.  The  nature  of  the  proteids  is  also  of  importance. 
Unboiled  fibrin  is,  relatively  to  most  other  albuminous  bodies,  dissolved  so 
very  quickly  that  the  digestion  test  vrith  raw  fibrin  gives  an  incorrect  idea 
of  the  power  of  trypsin  to  dissolve  coagulated  albuminous  bodies  in  general. 
An  accnnndation  of  products  of  digestion  tends  to  hinder  the  trypsin 
digestion. 

The  Products  of  the  Trypsiii  Digestion.  In  the  digestion  of  unboiled 
fibrin  a  globulin  which  coagulates  at  +  55-60°  C.  may  be  obtained  as  an 
intermediate  product  (Herrmann*),  iloreover  from  fibrin,  as  well  as 
from  other  albuminous  bodies,  emanate  cdbumoses  and  j^^pfone.,  Icucin., 
tg rosin,  and  aspartic  acid,  a  little  lysin,  lysatinin  (Hedin),  arginin  and 
histidin  (Kutscher*),  and  ammonia  (Hirschler''),  and  also  the  so-called 
protcinchromogen  or  tryptophan.  "When  putrefaction  has  not  been  entirely 
prevented  numerous  other  bodies  appear  which  will  be  sjioken  of  later  in 
connection  with  the  putrefaction  process  going  on  in  the  intestine.  In  the 
trypsin  digestion,  in  contrast  to  the  pepsin  digestion,  pure  peptones,  not 
precipitated  by  ammonium  sulphate,  are  relatively  easily  and  quickly 
formed.  The  peptone,  according  to  Kuhne,  consists  entirely  of  anti- 
peptone,  and  the  above-mentioned  decomposition  products,  leucin  and  the 
others,  are  formed  by  the  decomposition  of  the  hemipeptone  (see  Chapter 
II). 

Proteinchromogen *  or  tryptophan''  is  a  cleavage  product  appearine:  in  the  tryptic 
digtstion  of  albiuninous  bodies  and  whicli  gives  a  reddish-violet  product,  so-culled  pro- 
teinclironi,  witli  chlorine  or  bromine.  According  to  Nencki  at  least  two  dilforent  bodies 
with  iineiiual  amounts  of  bromine  are  ()l)taiued  on  adding  bromine.  One  of  these  seems 
to  stand  in  close  connection  to  luvmatoporphyriu,  or  bilirubin,  ami  the  other  to  the 
animal  mehiuins.     In  the  digestion  mixture,  freed  from  albumoses  by  ammonium  sul- 

■'  Lindberger,  Maly's  Jahresber  ,  Bd.  13;  Kachford  and  Southgate,  Medical  Record, 
1895;  Chittenden  and  Albro,  Amer.  Journ.  of  Physiol.,  Vol.  1,  1898. 
••^  Skan.  Arch.  f.  Physiol.,  Bd.  3. 
»  Zeitschr.  f.  physiol.  Chem..  Bd.  11. 

*  Hedin,  see  Drechsel,  "  Abhau  der  Eiweissstoffe  in  Du  Bois- Raymond's  Arch.,  1891; 
Kutscher,  Zeitschr.  f.  physiol.  Chera.,  Bd.  25. 

''  Ihid.,  Bd.  10,  S.  302. 

*  Stadelmann,  Zeitschr.  f   Biologic,  Bd.  26. 
^  Neumeister,  ihid.,  Bd.  26,  S.  329. 


290  DIGESTION. 

pbate,  KurAjEFf'  has  detected  at  least  three  proteiuchroms,  one  a  bluish-violet  bodjr 
with  at  least  35.'?  bromine,  another  red  with  21%  bromine,  and  thirdly  a  brown  or  black 
body.  By  the  action  of  chlorine  Beitler'*  obtained  a  red  product,  chloroproteiuchrom, 
which  corresponds  to  the  formula  CgeHneClsNsiOsiS.  This  product  is,  like  protein- 
chromoo-eu,  readily  decomposed.  The  proteinchromogen  diffuses  through  membranes 
and  is  precipitated  by  phospho-tungstic  acid,  but  not  by  metallic  salts. 

The  action  of  trypsin  on  other  bodies  lias  not  been  thoroughly  studied. 
An  enzyme  has  been  found  in  the  pancreas  of  the  pig  and  certain  herbivora, 
which  is  not  identical  with  trypsin  and  which  causes  the  coagulation  of 
neutral  or  alkaline  milk  (Kuhne  and  Roberts). 

According  to  Halliburton  and  Brodie  '  casein  is  transformed  by  the 
pancreatic  juice  of  the  dog  into  "  pancreatic  casein,"  a  substance  which  in 
regard  to  solubility  stands  between  casein  and  paracasein  (see  Chapter  XIV) 
and  which  is  converted  into  this  last  substance  by  rennin.  The  nucUins 
and  ineudo-nudeins  are  dissolved  by  the  alkaline  pancreatic  juice  and  at 
least  in  part  further  digested.  Gelatin  is  dissolved  by  the  pancreatic  juice 
and  is  converted  into  gelatin-peptone.  According  to  KuHisrE  and  Ewald  * 
neither  glycocoU  nor  leuciu  is  formed.  The  gelatin- forming  substance  of 
the  connective  tissues  is  not  directly  dissolved  by  trypsin,  but  only  after  it 
has  been  treated  with  acids  or  soaked  in  water  at  +  70°  C.  By  the  action 
of  trypsin  on  hyalin  cartilage  the  cells  dissolve,  leaving  the  nucleus.  The 
basis  is  softened  and  shows  an  indistinctly  constructed  network  of  collagen- 
ous si^stance  (Kuhne  and  Ewald).  The  elastic  substance^  the  struc- 
ttireless  membrane,  and  the  membrane  of  the  fat-cells  are  also  dissolved. 
Parenchymatous  organs,  such  as  the  liver  and  the  muscles,  are  dissolved  all 
bnt  the  nucleus,  connective  tissue,  fat-corpuscles,  and  the  remainder  of  the 
nervous  tissue.  If  the  muscles  are  boiled,  then  the  connective  tissue  is  also 
dissolved.  Mucin  and  certain  nucleins  are  dissolved  and  split  by  trypsin 
solutions.  Oxyhmmoglobin  is  decomposed  by  trypsin  with  the  splitting  off 
of  hsematin.  Hcemoglobin,  on  the  contrary,  when  the  access  of  oxygen  is 
completely  prevented,  is  not  decomposed  by  trypsin  (Hoppe-Setler'). 
Trypsin  does  not  act  on  fats  or  carbohydrates. 

It  has  already  been  brought  out  above  that  trypsin  does  not  exist 
ready  formed  in  the  gland,  but  more  likely,  as  Heidenhain  has  shown,  the 
gland  contains  a  corresponding  zymogen.  The  maximum  quantity  of 
such  zymogen  in  the  gland  occurs  14-16-18  hours  after  a  full  meal,  and 
the  minimum  G-10  hours  after.  This  zymogen  is  not  converted  by 
glycerin  into  trypsin,  but  is  easily  changed  by  water  and  acids.     A  soda 

•  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

»  Nencki,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  28  ;  Beitler,  ihid.,  Bd.  31. 

3  Kilhne  and  Roberts,  Maly's  .Jahresber. ,  Bd.  9,  S.  224  ;  also  Sidney  Edkins,  Journal 
of  Physiology,  Vol.  12,  which  contains  all  the  literature.  Halliburton  and  Brodie,  ibid.. 
Vol.  20. 

"  Verb.  d.  nat'arh.-med.  Vereius  zu  Heidelberg  (N.  F.},  Bd.  1. 

'  Physiol.  Chem.,  S.  207. 


CHEMICAL   PROCESSES  IN   THE  INTESTINE.  291 

solntioii  of  1-1.5^,  on  the  contrary,  prevents  almost  entirely  the  conversion 
of  tlie  zymogen.  If  we  allow  the  gland  to  lie  in  the  air  it  gradually 
becomes  acid,  and  this  leads  to  the  formation  of  an  enzyme  in  whicli  tlio 
oxygen  seems  to  be  active,  as  is  usual  in  the  conversion  of  the  zymogen 
into  trypsin.  It  is  very  probable  also  that  the  two  other  enzymes  are 
formed  from  corresponding  zymogens,  and  this  has  been  shown  by  Livi:k- 
SIDGE '  to  be  plausible  in  the  case  of  the  diastatic  enzyme. 

y.   The  Chemical   Processes  in  the   Intestine. 

The  action  which  belongs  to  each  digestive  secretion  may  be  essentially 
changed  by  mixing  with  other  digestive  fluids;  and  since  the  digestive 
fluids  which  How  into  the  intestine  are  mixed  with  still  another  lluid,  the 
bile,  it  will  be  readily  understood  that  the  combined  action  of  all  these 
fluids  in  the  intestine  makes  the  chemical  processes  going  on  therein  very 
complicated. 

As  the  acid  of  the  gastric  juice  acts  destructively  on  ptyalin,  this  enzyme 
has  no  further  diastatic  action,  even  after  the  acid  of  the  gastric  juice  has 
been  neutralized  in  the  intestine.  The  bile  has,  at  least  in  certain  animals, 
a  faint  diastatic  action  which  in  itself  can  hardly  be  of  any  great  impor- 
tance, but  which  shows  that  the  bile  has  not  a  preventive  but  rather  a 
beneficial  influence  on  the  energetic  diastatic  action  of  the  pancreatic  juice, 
Martin  and  Willliams*  have  observed  a  beneficial  action  of  the  bile  on 
the  diastatic  action  of  the  pacreas  infusion.  To  this  may  be  added  that  the 
organized  ferments  which  occur  habitually  in  the  intestine  and  sometime? 
in  the  food  have  partly  a  diastatic  action  and  partly  produce  a  lactic-acid  and 
butyric-acid  fern)entation.  The  maltose  which  is  formed  from  the  starch 
seems  to  be  converted  into  glucose  in  the  intestine.  Cane-sugar  is  inverted 
in  the  intestine,  and,  at  least  in  certain  animals,  also  lactose.'  Cellulose, 
especially  the  liner  and  more  tender  kind,  is  undoubtedly  partly  dissolved 
in  the  intestine;  the  products  thus  formed  are  not  very  well  known.  It  has 
been  shown  by  Tappeiner  that  cellulose  may  undergo  fermentation,  caused 
by  the  action  of  micro-organisms  with  the  production  of  marsh-gas,  acetic 
acid,  and  butyric  acid;  still  we  do  not  know  to  what  extent  the  cellulose  ia 
destroyed  in  this  way.* 

The  bile,  especially  dog-bile,  has,  according  to  Moore  and  Rockwood,' 

'  Journ.  of  Physiol..  Vol.  8. 

'  Proceedings  of  the  Roy.  Soc. ,  Vols.  45  and  48. 

'  See  literature  foot-note  ?>,  page  280.  and  foot-note  1.  page  281. 

*  On  the  digestion  of  cellulose  see  Henneberg  and  Stolimann,  Zeitschr.  f.  Biologfe, 
Bd.  21,  S.  613  ;  v.  Knierieni,  ibid.,  S.  67;  Hofnieister,  Arch.  f.  wiss.  u.  prakt.  Thier- 
lieilkunde,  Bd.  11  ;  AVeiske,  Zeitschr.  f.  Biologie,  Bd.  22,  S.  373  ;  Tappeinev,  ibid.,  Bdd. 
20  and  24  ;  and  Mallivre,  PflUger's  Arch.,  Bd.  49. 

'  Proceedings  of  Roy.  Soc,  Vol.  60,  and  Journ.  of  Physiol.,  Vol.  21. 


292  DIGESTION. 

the  property  of  dissolving  fatty  acids  to  a  rather  high  degree  and  hence  it 
can  perhaps  accelerate  the  absorption  of  fatty  acids  split  off  by  the  pan- 
creatic jaice.  It  is,  however,  "without  donbt  of  greater  importance  that  the 
bile,  as  Xexcki  and  Rachford  '  have  shown,  facilitates  the  fat-splitting 
action  of  the  pancreatic  jaice.  The  fatty  acids  combine  with  the  alkalies 
of  the  intestinal  and  pancreatic  juices,  producing  soaps  which  are  partly 
absorbed  as  such  and  partly  exercise  a  powerful  action  on  the  absorption  of 
the  fats. 

If  to  a  soda  solution  of  about  1-3  p.  m.  j^a^COj  we  add  pure,  perfectly 
neutral  olive-oil  in  not  too  large  quantity,  we  obtain,  after  vigorous  shaking, 
a  transient  emulsion.  If,  on  the  contrary,  we  add  to  the  same  quantity  of 
soda  solution  an  equal  amount  of  commercial  olive-oil  (which  always  con- 
tains free  fatty  acids),  we  need  only  turn  the  vessel  over  for  the  two  liquids 
tD  mix  and  immediately  we  have  a  very  finely  divided  and  permanent 
emulsion  making  the  liquid  appear  like  milk.  The  free  fatty  acids  of  the 
always  somewhat  rancid  commercial  oil  combine  with  the  alkali  to  form 
soaps  which  act  to  emulsify  the  fats  (Brucke,  Gad,  Loewenthal"). 
This  emulsifying  action  of  the  fatty  acids  split  off  by  the  pancreatic  juice  is 
undoubtedly  assisted  by  the  habitual  occurrence  of  free  fatty  acids  in  the 
food,  and  also  by  the  splitting  off  of  fatty  acids  from  the  neutral  fats  by  the 
putreiaction  in  the  intestine.  These  fatty  acids  must  combine  with  the 
alkalies  in  the  intestine  and  form  soaps. 

As  the  greater  part  of  the  absorbed  fat  is  again  found  in  the  chyle  as  an 
emulsion  we  generally  consider  the  formation  of  an  emulsion  by  the  aid  of 
the  soaps  as  of  great  importance  in  the  absorption  of  fats.  The  correctness 
of  this  view,  and  questions  in  regard  to  the  absorption  of  fats,  will  be 
discussed  later  in  connection  with  absorption.  It  is  sufficient  to  state  here 
that,  according  to  the  unanimous  experience,  the  united  action  of  the  bile 
and  pancreatic  juice  favor  the  absorption  of  fats. 

Bile  completely  prevents  pepsin  digestion  in  artificial  digestion,  because 
it  retards  the  swelling  up  of  the  proteids.  The  passage  of  bile  into  the 
stomach  during  digestion,  on  the  contrary,  seems  according  to  several  inves- 
tigators, especially  Oddi  and  Dastre,'  to  have  no  retarding  action  on 
stomachic  digestion.  Bile  has  no  solvent  action  on  proteids  in  neutral  or 
alkaline  reaction,  but  still  it  may  have  an  influence  on  proteid  digestion  in 
the  intestine.  The  acid  contents  of  the  stomach,  containing  an  abundance 
cf  proteids,  give  with  the  bile  a  precipitate  of  proteids  and  bile-acids.     This 


'  Nencki,  Arch.  f.  exp.  Path.  u.  Pljarm.,  Bd.  20  ;  Rachford,  Journal  of  Physiol., 
Vol.  12. 

*  Brlicke,  Wien.  Sitzungsber.,  Bd.  61,  Abth.  2  ;  Gad.  Du  Bois-Reymond's  Arch., 
1878;  Loewenlhal.  ihuL,  1897. 

»  Oddi  Ref.  ia  Centralbl.  f.  Physiol.,  Bd.  1.  S.  312  ;  Dastre,  Arch,  de  Physiol.  (5), 
Tome  2,  p.  316. 


THE  BILE  IN  THE  INTESTINE.  293 

])recipitate  carries  a  part  of  the  pepsin  witli  it,  and  for  this  reason,  and  alao 
on  account  of  the  partial  or  conijjlete  neutralization  of  the  ucid  of  the 
gastric  juice  by  the  alkali  of  the  bile  and  the  pancreatic  juice,  the  pepsin 
digestion  cannot  proceed  further  in  the  intestine.  On  the  contrary,  the 
bile  does  not  disturb  the  digestion  of  proteids  by  the  pancreatic  juice  in  the 
intestine.  Theaction  of  these  digestive  secretions,  as  above  stated,  is  not 
disturbed  by  the  bile,  especially  not  by  the  faintly  acid  reaction  due  to 
organic  acids  which  are  habitually  found  in  the  upper  parts  of  the  intestine. 
In  a  dog  killed  while  digestion  is  going  on,  the  faintly  acid,  bile-containing 
material  of  the  intestine  shows  regularly  a  strong  digestive  action  on 
proteids. 

Tiie  precipitate  formed  on  the  meeting  of  the  acid  contents  of  the 
stomach  with  the  bile  easily  redissolves  in  an  excess  of  bile  and  also  in  the 
NaCl  formed  in  the  neutralization  of  the  hydrochloric  acid  of  the  gastric 
juice.  This  may  take  place  even  under  faintly  acid  reaction.  Since  in 
man  the  excretory  ducts  of  the  bile  and  the  pancreatic  juice  open  near  one 
another,  in  consequence  of  which  the  acid  contents  of  the  stomach  are 
probably  immediately  in  great  part  neutralized  by  the  bile  as  soon  as  it 
enters,  it  is  doubtful  whether  a  ju-ecipitation  of  proteids  by  the  bile  occurs 
in  tiie  intestine. 

Besides  the  previously  mentioned  processes  caused  by  enzymes,  there 
are  others  of  a  different  nature  going  on  in  the  intestine,  namely,  the 
fermentation  and  jiutrefaction  processes  caused  by  micro-organisms.  These 
are  less  intense  in  the  upper  parts  of  the  intestine,  but  increase  in  intensity 
towards  the  lower  part  of  the  same,  and  decrease  in  the  large  intestine 
because  of  the  absorption  of  water.  Fermentation  but  not  putrefaction 
processes  occur  in  the  small  intestine  as  long  as  the  contents  are  strongly 
acid.  Macfadten",  M.  Kencki,  and  N.  Sieber  '  have  investigated  a  case 
of  human  anus  praeternaturalis,  in  which  the  fistula  occurred  at  the  lower 
end  of  the  ileum,  and  they  w^ere  able  to  investigate  the  contents  of  the 
intestine  after  it  had  been  exposed  to  the  action  of  the  mucous  membrane 
of  the  entire  small  intestine.  The  mass  was  yellow  or  yellowish  brown,  due 
to  bilirubin,  had  an  acid  reaction  which,  calculated  as  acetic  acid,  amounted 
to  1  p.  m.  The  contents  were  nearly  odorless,  having  an  empyreumatic  odor 
recalling  that  of  volatile  fatty  acids,  and  only  seldom  had  a  putrid  odor 
recalling  that  of  indol.  The  essential  acid  present  was  acetic  acid,  accom- 
panied with  fermentation  lactic  acid  and  paralactic  acid,  volatile  fatty  acids, 
succinic  acid,  and  bile-acids.  Coagnlable  proteids,  peptone,  mucin,  dextrin, 
dextrose,  and  alcohol  were  present.  Leucin  and  tyrosin  could  not  be 
det,ected. 

According  to  the  above-mentioned  investigators,  the  proteids  are  only  to 


ch.  f.  fxp.  Path.  u.  Pliaini..  Bd.  28. 


294  DIGESTION. 

a  very  slight  extent,  if  at  all,  decomposed  by  the  microbes  in  the  small 
intestine  of  man.  The  microbes  present  in  the  small  intestine  preferably 
decompose  the  carbohydrates,  forming  ethyl  alcohol  and  the  above-men- 
tioned organic  acids.  Free  hydrochloric  acid  does  not  occur  in  the  small 
intestine,  and  it  is  the  organic  acids  that  prevent  the  putrefaction  of  the 
proteids  in  the  intestine. 

Further  investigations  of  Jakowsky  '  lead  to  the  same  result,  namely, 
that  in  man  the  putrefaction  of  the  proteids  does  not  take  place  in  the  small 
but  in  the  large  intestine.  This  putrefaction  of  the  proteids  is  not  the 
same  as  the  pancreatic  digestion,  and  these  two  processes  are  essentially 
different  because  of  the  products  they  yield.  In  the  pancreatic  digestion 
of  proteids  there  are  formed,  as  far  as  we  know  at  present,  besides  albumoses 
and  peptones,  bases,  proteinchromogen,  amido-acids,  and  ammonia.  In 
the  putrefaction  of  the  proteids  we  have,  indeed,  the  same  products  formed 
at  the  beginning,  but  the  decomposition  proceeds  considerably  further  and 
a  number  of  products  are  developed  which  have  become  known  through  the 
labors  of  numerous  investigators,  Nencki,  Baumann",  Brieger,  H.  and 
E.  Salkowski,  and  their  pupils.  The  products  which  are  formed  in  the 
putrefaction  of  proteids  are  (in  addition  to  albumoses,  peptofies,  amido-acids, 
and  cfmmonia)  indol,  skatol,  paracresol,  phenol,  plienyl-propionic  acid,  and 
phetnf I- acetic  acid,  also  jM^aoxypJieni/ 1- acetic  acid  and  liydrojxtracumaric  acid 
(besides  paracresol,  produced  in  the  putrefaction  of  tyrosin),  volatile  fatty 
acids,  carbon  dioxide,  hydrogen,  marsh-gas,  methylmercaptan,  and  sulphu- 
retted hydrogen.  In  the  putrefaction  of  gelatin  neither  tyrosin  nor  indol  is 
formed,  while  glycocoll  is  produced. 

Among  these  products  of  decomposition  a  few  are  of  special  interest 
because  of  their  behavior  within  the  organism  and  because  after  their 
absorption  they  pass  into  the  urine.  A  few,  such  as  the  oxyacids,  pass 
unchanged  into  the  urine.  Others,  such  as  phenols,  are  directly  trans- 
formed into  ethereal  sulphuric  acids  by  synthesis,  and  are  eliminated  as  such 
by  the  urine;  on  the  contrary,  others,  such  as  indol  and  skatol,  are  only 
converted  into  ethereal  sulphuric  acids  after  oxidation  (for  details  see 
Chapter  XV).  The  quantity  of  these  bodies  in  the  urine  varies  also  with 
the  extent  of  the  putrefactive  processes  in  the  intestine;  at  least  this  is  true 
for  the  ethereal  sulphuric  acids.  Their  quantity  increases  in  the  urine  with 
a  stronger  putrefaction,  and  the  reverse  takes  place,  as  Baumann  °  has 
shown  by  experiments  on  dogs,  when  the  intestine  has  been  disinfected  by 
calomel,  namely,  they  then  disappear  from  the  urine. 

Among  the  above-mentioned  putrefactive  products  in  the  intestine  the 
two  following,  indol  and  skatol,  should  be  especially  noted. 

•  Arch,  des  Scieiic.  biol.  de  St.  Petersbourg,  Tome  1. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 


PUTREFACTION  PRODUCTS,  INDOL,   SKATOL.  296 

CH 

Indol,    C,H,^  =  C,II^  CII,    aud     Skatol,    or     methyl-indol, 

\      / 
NU 

C.CH. 

C,H,X  —  0,11,  CH,  are  two  bodies  which  stand  in  close  relationship 

\       / 
Nil 

to  the  indigo  substances  and  are  formed  in  variable  quantities  from  proteid 

sabstances  under  different  conditions.     Hence  they  occur  habitually  in  the 

human   intestinal   canal   and,  after   oxidation  into  indoxyl  and    skatoxyl 

respectively,  pass,  at   least   partly,   into  the  urine   as   the   corresponding 

ethereal  sulphuric  acids  and  also  as  glycnronic  acids. 

These  two  bodies  have  been  prepared  synthetically  in  nianv  ways.  Both 
may  be  obtained  from  indigo  by  reducing  it  with  tin  and  hydrochloric  acid 
and  heating  this  reduction  product  witli  zinc-dust  (Baeyer').  Indol  may 
be  formed  from  skatol  by  passing  it  through  a  red-hot  tube.  Indol  sus- 
pended in  water  is  in  part  oxidized  into  indigo-blue  by  ozone  (Nexcki'). 

Indol  and  skatol  crystal lize'in  shining  leaves,  and  their  melting-points 
are  +  52°  and  95°  C.  respectively.  Indol  has  a  peculiar  excrementitious 
odor,  while  skatol  has  an  intense  fetid  odor  (skatol  obtained  from  indigo  is 
odorless).  Both  bodies  are  easily  volatilized  by  steam,  skatol  more  easily 
than  indol.  They  may  both  be  removed  from  the  watery  distillate  by  ether. 
Skatol  is  the  more  insoluble  of  the  two  in  boiling  water.  Both  are  easily 
soluble  in  alcohol,  and  give  with  picric  acid  a  combination  consisting  of  red 
crystalline  needles.  If  a  mixture  of  the  two  picrates  be  distilled  with 
ammonia,  they  both  pass  over  without  decomposition;  while  if  they  are 
distilled  with  caustic  soda,  the  indol  but  not  the  skatol  is  decomposed. 
The  watery  solution  of  indol  gives  with  fuming  nitric  acid  a  red  liquid,  and 
then  a  red  precijiitate  of  nitroso-indol  nitrate  (Nencki  ").  It  is  better  first 
to  add  two  or  three  drops  of  nitric  acid,  and  then  a  2^  solution  of 
potassium  nitrite,  drop  by  drop  (Salkowski  *).  Skatol  does  not  give  this 
reaction.  An  alcoholic  solution  of  indol  treated  with  hydrochloric  acid 
colors  a  pine  chip  cherry-red.  Skatol  does  not  give  this  reaction.  Indol 
gives  a  deep  reddish-violet  color  with  sodium  nitroprusside  and  alkali 
(Legal's  reaction).  On  acidifying  with  hydrochloric  acid  or  acetic  acid 
the  color  becomes  true  blue.     Skatol  does  not  act  the  same.     The  alkaline 

'  Annal.  d.  Cliem.  u.  Pbarm.,  Bd.  140,  and  Supplbd.  7,  S.  56  ;  also  Ber.  d.  deutsch. 
cbem.  Gesellsch.,  Bd.  1. 

*  Ber.  d.  deutsch.  cbem.  Gesellscb.,  Bd.  8,  S.  727.  and  ibid.,  S.  722  and  1517. 

» Ibid. 

*■  Zeitscbr.  f.  pbysiol    Cbem..  Bd.  P,  S.  447. 


296  DIGESTION. 

solution  is  yellow  and  becomes  violet  on  acidifying  with  acetic  acid  and 
boiling.  Skatol  dissolves  in  concentrated  hydrochloric  acid  with  a  violet 
coloration.  On  warming  skatol  with  sulphuric  acid  a  beautiful  purple-red 
coloration  is  obtained  (CiAMiciAisr  and  Magnaniki  '). 

For  the  detection  of  indol  and  skatol  in,  and  their  preparation  from, 
excrement  and  putrefying  mixtures,  the  main  points  of  the  usual  method 
are  as  follows:  The  mixture  is  distilled  after  acidifying  with  acetic  acid; 
the  distillate  is  then  treated  with  alkali  (to  combine  with  any  phenol  which 
may  be  present)  and  again  distilled.  From  this  second  distillate  the  two 
bodies,  after  the  addition  of  hydrochloric  acid,  are  precipitated  by  picric 
acid.  The  picrate  precipitate  is  then  distilled  with  ammonia.  The  two 
bodies  are  obtained  from  the  distillate  by  repeated  shaking  with  ether  and 
evaporation  of  the  several  ethereal  extracts.  The  residue,  containing  indol 
and  skatol,  is  dissolved  in  a  very  small  quantity  of  absolute  alcohol  and 
treated  with  8-10  vols,  of  water.  Skatol  is  precipitated,  but  not  the  indol. 
The  further  treatment  necessary  for  their  separation  and  purification  will 
be  found  in  other  works. 

The  gases  which  are  produced  by  the  decomposition  processes  are  mixed 
in  the  intestinal  tract  with  the  atmospheric  air  swallowed  with  the  saliva, 
and  as  the  gas  developed  in  the  decomposition  of  different  foods  varies,  so 
the  miiture  of  gases  after  various  foods  shonld  have  a  dissimilar  composi- 
tion. This  is  found  to  be  true.  Oxygen  is  found  only  in  very  faint  traces 
in  the  intestine;  this  may  be  accounted  for  in  part  by  the  formation  of 
reducing  substances  in  the  fermentation  processes  which  combine  with  the 
oxygen,  and  partly,  perhaps  chiefly,  to  a  diffusion  of  the  oxygen  through 
the  tissues  of  the  Avails  of  the  intestine.  To  show  that  these  processes  take 
place  mainly  in  the  stomach  the  reader  is  referred  to  page  371,  on  the  com- 
position of  the  gases  of  the  stomach.  Nitrogen  is  habitually  found  in  the 
intestine,  and  it  is  probably  due  chiefly  to  the  swallowed  air.  The  carbon 
dioxide  originates  partly  from  the  contents  of  the  stomach,  partly  from  the 
putrefaction  of  the  proteids,  partly  from  the  lactic-acid  and  butyric-acid 
fermentation  of  carbohydrates,  and  partly  from  the  setting  free  of  carbon 
dioxide  from  the  alkali  carbonates  of  the  pancreatic  and  intestinal  juices  by 
their  neutralization  through  the  hydrochloric  acid  of  the  gastric  juice  and 
by  organic  acids  formed  in  the  fermentation.  Hydrogen  occurs  in  largest 
q:iantities  after  a  milk  diet,  and  in  smallest  quantities  after  a  purely  meat 
diet.  This  gas  seems  to  be  formed  chiefly  in  the  butyric-acid  fermentation 
of  carbohydrates,  although  it  may  occur  in  large  quantities  in  the  putrefac- 
tion of  proteids  under  certain  circumstances.  There  is  no  doubt  that  the 
methylmercaptan  and  stdphureited  hydrogen  which  occurs  normally  in  the 
intestine  originates  from  the  proteids.  The  taarsh-gas  undoubtedly  origi- 
tiates  in  the  putrefaction  of  proteids.     As  proof  of  this  Ruge'  foun'd  2{'>A5f^. 

'  Ber.  (1.  rleutsdi.  chem.  Gesellscli.,  Bd.  21,  S.  1928. 
*  Wieu.  Sitzungsber.,  Bd.  44. 


PUTREFACTION  IN  THE  INTESTINE.  297 

marsh-gas  in  the  linnian  intestine  after  a  meat  diet.  lie  found  a  still 
greater  quantity  of  this  gas  after  a  vegetable  (legnminons)  diet  ;  this 
coincides  with  the  observation  that  marsli-gas  may  be  produced  by  a 
fermentation  of  carbohydrates,  but  especially  of  cellulose  (Tai'EINp:r '). 
Such  an  origin  of  marsh-gas,  especially  in  herbivora,  is  to  be  expected.  A 
small  part  of  the  marsh-gas  and  carbon  dioxide  may  also  depend  on  the 
decomposition  of  lecithin  (Hasebroek'). 

Putrefaction  in  the  intestine  not  only  depends  upon  the  composition  of 
the  food,  but  also  upon  the  albuminous  secretions  and  the  bile.  Among 
the  constituents  of  bile  vs^hich  are  changed  or  decomposed  we  have  not  only 
the  pigments — the  bilirubin  yields  urobilin  and  a  brown  pigment — but  also 
the  bile-acids,  especially  taurocholic  acid.  Glycocholic  acid  is  more  stable, 
and  a  part  is  found  unchanged  in  the  excrement  of  certain  animals,  wliile 
taurocholic  acid  is  so  completely  decomposed  that  it  is  entirely  absent  in 
the  fffices.  In  the  foetus,  in  whose  intestinal  tract  no  putrefaction  processes 
occur,  we  find,  on  the  contrary,  undecomposed  bile-acids  and  bile-pigments 
in  the  contents  of  the  intestine.  The  reduction  of  bilirubin  into  urobilin 
does  not,  according  to  Macfadyen,  Nencki,  Sieber,  and  Harley,'  take 
place  in  man  in  the  small  but  in  the  large  intestine. 

That  the  secretions  rich  in  proteids  are  destroyed  in  putrefaction  in  the 
intestine  follows  from  the  fact  that  putrefaction  may  also  continue  during 
complete  fasting.  From  the  observations  of  Muller*  on  Cetti  it  was 
found  that  the  elimination  of  indican  during  starvation  rapidly  decreased 
and  after  the  third  day  of  starvation  it  had  entirely  disappeared,  while  the 
phenol  elimination,  which  at  first  decreased  so  that  it  was  nearly  minimun), 
increased  again  from  the  fifth  day  of  starvation,  and  on  the  eighth  or  ninth 
day  it  was  three  to  seven  times  as  much  as  in  man  under  ordinary  circum- 
stances. In  dogs,  on  the  contrary,  the  elimination  of  indican  during 
starvation  is  considerable,  but  the  phenol  elimination  is  slight.  Among 
the  secretions  which  undergo  putrefaction  in  the  intestine,  the  pancreatic 
juice,  which  putrefies  most  readily,  takes  first  place. 

From  the  foregoing  facts  we  conclude  that  the  products  formed  by  the 
putrefaction  in  the  intestine  are  in  part  the  same  as  those  formed  in  diges- 
tion. The  putrefaction  may  be  of  benefit  to  the  organism  so  far  as  tlie 
formation  of  such  products  as  albumoses,  peptones,  and  perhaps  also  certain 
amido-acids  is  concerned.  The  question  has  indeed  been  asked  (Pasteur), 
is  digestion  possible  without  micro-organisms  ?  Nuttal  and  Tiiierfelder  ' 
have  shown  tha-t  guinea-pigs  removed  from  the  uterus  of  the  mother  by 

'  Zeitscli.  f.  Biologic,  Bdd.  20  and  24. 
'  Zeitschr.  f.  pbysiol.  Cliem.,  Bd.  12. 
^Iim-iey^  Brit   ■^l^,^^   Jouru.,  1896. 

*  Beiliu.  klin.  Wocheuscbr.,  18S7. 

*  Zuitschr.  f.  pbysiol.  Cbem.,  Bdd.  21  and  22. 


298  DIGESTION. 

Caesarian  section  coakl  with  sterile  air  digest  well  and  assimilate  sterile  food 
(milk  or  crackers)  iu  the  complete  absence  of  bacteria  in  the  intestine,  and 
grew  perfectly  normal  and  increased  in  weight. 

The  bacterial  action  in  the  intestine  is  not  necessary  at  least  for  certain 
varieties  of  food.  That  they  may  be  of  importance  to  the  organism  has 
been  stated  above;  but  this  action  may,  by  the  formation  of  farther  cleavage 
products,  be  a  loss  of  valuable  material  to  the  organism,  and  it  is  therefore 
important  that  putrefaction  in  the  intestine  is  kept  within  certain  limits. 
If  an  animal  is  killed  while  digestion  in  the  intestine  is  going  on,  the  con- 
tents of  the  small  intestine  give  out  a  peculiar  but  not  putrescent  odor. 
Also  the  odor  of  the  contents  of  the  large  intestine  is  far  less  offensive  than 
a  putrefying  pancreas  infusion  or  a  putrefying  mixture  rich  in  proteid. 
From  this  we  may  conclude  that  putrefaction  in  the  intestine  is  ordinarily 
not  nearly  as  intense  as  outside  of  the  organism. 

It  seems  thus  to  be  prov^ided,  under  physiological  conditions,  that  putre- 
faction shall  not  proceed  too  far,  and  the  factors  which  here  come  under 
consideration  are  probably  of  different  kinds.  Absorption  is  undoubtedly 
one  of  the  most  important  of  them,  and  it  has  been  proved  by  actual  obser- 
vation that  the  putrefaction  increases,  as  a  rule,  as  the  absorption  is  checked 
and  fliiid  masses  accumulate  in  the  intestine.  The  character  of  the  food 
also  has  an  unmistakable  influence,  and  it  seems  as  if  a  large  quantity  of 
carbohydrates  in  the  food  acts  against  putrefaction  (Hirschler ').  It  has 
been  shown  by  Pohl,  Biernacki,  Rovighi,  Winterxitz,  and  Schmitz  ' 
that  milk  and  kephir  have  a  specially  strong  preventive  action  on  putrefac- 
tion. This  action,  according  to  Schmitz,  is  not  due  to  the  casein,  but 
■chiefly  to  the  lactose  and  also  in  part  to  the  lactic  acid. 

A  specially  strong  preventive  action  on  putrefaction  has  been  ascribed 
for  a  long  time  to  the  bile.  This  anti-putrid  action  is  not  due  to  neutral 
or  faintly  alkaline  bile,  which  itself  easily  putrefies,  but  to  the  free  bile- 
acids,  especially  taurocholic  acid  (Maly  and  Emich,  Lindberger '). 
There  is  no  question  that  tlie  free  bile-acids  have  a  strong  preventive  action 
on  putrefaction  outside  of  the  organism,  and  it  is  therefore  difficult  to  deny 
such  an  action  in  the  intestine.  Xotwithstanding  this  the  anti-putrid 
action  of  the  bile  in  the  intestine  is  contradicted  by  certain  investigators 
(VoiT,  lioHMAXN-,  HiRSCHLER  and  Terray  ').     MossE  '  has  recently  given 


'  Zeitschr.  f.  physiol.  Chcm..  Bd.  10,  S.  306, 

■^  Ibid.,  Bd.  17,  S.  401,  which  gives  references  to  tlie  older  literature,  and  Bd.  19. 
See  also  Salkowski,  Centralbl.  f.  d.  med,  Wiss.,  1893,  8.  4G7,  and  Seelig,  Virchow's 
Arch.,  Bd.  140, 

'  Maly  and  Emich,  Monatshefte  f.  Cheni.,  Bd.  4  ;  Lindberger,  1.  c. 

*Voil,  Beitr.  zur  Biologic,  .Jubiliiiunschrift,  SUUIgurt,  18b2  ;  Rohmaun,  PflUger's 
Arch.,  Bd,  29;  Hirscliler  and  Terray,  Maly's  Juhrcsber.,  Bd.  26. 

6  Zeitschr.  f.  kliu.  Med,,  Bd.  36. 


rUTREF ACTION  IN   TllK  INTESTINE.  299 

farther  proof  as  to  the  inability  of  neutral  bile  in  preventing  putrefaction. 
He  claims,  on  the  contrary,  that  it  has  a  temporal  retarding  action  on  the 
development  of  bacteria. 

Biliary  fistula}  have  been  established  so  as  to  study  the  importance  of  the 
bile  in  digestion  (SniwANN,  Hloxdlot,  I^iddkr  and  Schmidt,'  and 
others).  As  a  result  it  has  been  observed  that  with  fatty  foods  an  imperfect 
absorption  of  fat  regularly  takes  place,  and  the  excrements  cont;ain,  there- 
fore, an  excess  of  fat  and  have  a  light-gray  or  pale  color.  The  extent  of 
deviation  from  the  normal  after  the  operation  is  essentially  dependent  npon 
the  character  oi  the  food.  If  an  animal  is  fed  on  meat  and  fat,  then  the 
quantity  of  food  must  be  considerably  increased  after  the  operation,  other- 
wise the  animal  will  become  very  thin,  and  indeed  die  with  symptoms*of 
starvation.  In  these  cases  the  excrements  have  the  odor  of  carrion,  and 
this  was  considered  a  proof  of  the  action  of  the  bile  in  checking  putrefac- 
tion. The  emaciation  and  the  increased  want  of  food  depend,  naturallv, 
upon  tlie  imperfect  absorption  of  the  fats,  whose  high  calorific  value  is 
reduced  and  must  be  replaced  by  the  taking  up  of  larger  quantities  of  other 
nutritive  bodies.  If  the  quantity  of  proteids  and  fats  be  increased,  then 
this  last,  which  can  be  only  very  incompletely  absorbed,  accumulates  in  the 
intestine.  This  accumulation  of  the  fats  in  the  intestine  only  renders  the 
action  of  the  digestive  juices  on  proteids  more  difficult,  and  these  last 
increase  the  amount  of  putrefaction.  This  explains  the  appearance  of  fetid 
faeces,  whose  pale  color  is  not  due  to  a  lack  of  bile-pigments,  but  to  a 
surplus  of  fat  (KOiimaxn,  Voit).  If  the  animal  is,  on  the  contrary,  fed 
on  meat  and  carbohydrates,  it  may  remain  quite  normal,  and  the  leading 
off  of  the  bile  does  not  cause  any  increased  putrefaction.  The  carbo- 
hydrates may  be  uninterruptedly  absorbed  in  such  large  quantities  that  they 
replace  the  fat  of  the  food,  and  this  is  the  reason  why  the  animal  on  such  a 
diet  does  not  become  emaciated.  As  with  this  diet  the  putrefaction  in  the 
intestine  is  no  greater  than  under  normal  conditions  even  though  the  bile  is 
absent,  it  would  seem  that  the  bile  in  the  intestine  exercises  no  preventive 
action  on  putrefaction. 

The  researches  of  Landauer'  on  the  influence  of  the  bile  on  metabolism 
have  substantiated  the  earlier  observations  that  fats  are  as  poorly  absorbed 
in  dogs  with  biliary  fistula  and  the  carbohydrates  as  in  normal  animals. 
With  food  consisting  of  medium  amounts  of  proteids,  larger  amounts 
of  carbohydrates,  and  only  very  little  fat  the  deposition  of  proteid  took 
place  as  in  normal  animals.  On  feeding  with  sufficient  proteid  and  little 
fat  nitrogenous  equilibrium  occurred  also  in  a  fistula  dog,  but  first  with 

'  Schwjuin,  Mlilier's  Arcli.  f.  Anat.  u.  Physiol.,  1844;  Bloudlot,  cited  from  Bidder 
and  Schmidt,  VerdiunMigssUfte,  etc..  S.  98. 

•  Math.  u.  n;itur\v.  Beiieht  aus  Uugaru,  Bd.  13. 


300  DIGESTION. 

a  bodily  weight  less  than  iu  a  normal  auimal.  On  feeding  with  mediam 
quantities  of  proteid  and  more  fat,  with  which  a  deposition  of  profceid  took 
place  iu  a  normal  animal,  a  loss  of  proteid  was  observed  in  a  fistula  dog. 

To  this  conclusion  the  objection  may  be  made  that  the  carbohydrates, 
which  are  capable  of  checking  putrefaction,  can,  so  to  speak,  undertake 
the  anti-j^ntrid  action  of  the  bile.  But  as  we  also  have  cases  (in  dogs 
with  biliary  fistula)  where  the  intestinal  putrefaction  is  not  increased  with 
exclusive  meat  diet,'  still  itis  maintained  that  the  absence  of  bile  in  the 
intestine,  even  by  exclusive  carboyhdrate  food,  does  not  always  cause  an 
increased  patrefaction. 

Although  the  qnestion  how  the  putrefactive  processes  in  the  intestine 
under  physiological  conditions  are  kept  within  certain  limits  cannot  be 
answered  positively,  still  it  may  be  asserted  that  the  acid  reaction  of  the 
upper  parts  of  the  intestine,  and  the  absorption  of  water  in  the  lower  parts, 
are  important  factors. 

That  the  acid  reaction  in  the  intestine  has  a  preventive  infiuence  on  the 
putrefactive  processes  follows  from  the  existing  relation  between  the  degree 
of  acidity  of  the  gastric  juice  and  the  putrefaction  in  the  intestine.  After 
the  investigations  and  observations  of  Kast,  Stadelmann,  Wasbutzki, 
BiernA-CKI,  and  Mester  had  proved  that  an  increased  putrefaction  in  the 
intestine  occurred  when  the  quantity  of  hydrochloric  acid  in  the  gastric 
juice  was  diminished  or  deficient,  Schmitz^  has  lately  shown  in  man  that 
on  the  administration  of  hydrochloric  acid,  producing  a  hyperacidity  of  the 
gastric  juice,  the  putrefaction  in  the  intestine  may  be  checked.  The  ques- 
tion as  to  how  the  putrefaction  is  regulated  in  animals  where  the  intestinal 
contents  is  alkaline  all  along  the  intestine  (Moore  and  Rockwood  ^)  remains 
unsettled. 

Excrements.  It  is  evident  that  the  residue  which  remains  after  com- 
pleted digestion  and  absorption  in  the  intestine  must  be  different,  both 
qualitatively  and  quantitatively,  according  to  the  variety  and  quantity  of 
the  food.  In  man  the  quantity  of  excrement  from  a  mixed  diet  is  120-150 
grms.,  with  30-37  grms.  solids,  per  24  hours,  while  the  quantity  from  a. 
vegetable  diet,  according  to  Vorr,'  was  333  grms.,  with  75  grms.  solids. 
"With  a  strictly  meat  diet  the  excrements  are  scanty,  pitch-like,  and  colored 
nearly  black.  The  scanty  excrements  in  starvation  have  a  similar  appear- 
ance. A  large  quantity  of  coarse  bread  yields  a  great  amount  of  light- 
colored  excrement.  If  there  is  a  large  proportion  of  fat,  it  takes  a  li^^hter, 
clayey  appearance.  The  decomposition  products  of  the  bile-pigments  seem 
to  play  only  a  small  part  in  the  normal  color  of  the  fisces. 

'  See  Hurley  and  Tenay. 

'  Zeiischr.  f.  physiol.  Chein.,  Bd.  19,  S.  401,  wLicli  includes  all  the  pertinent  literature. 

».Jouni.  of  Pliysiol.,  Vol.  21. 

*  Zeilsclir.  f.  Biologic,  Bd.  25,  S.  2G4. 


EXCREMENTS.  301 

The  constituents  of  the  fteces  are  of  ilifTerent  kinds.  AVe  find  in  the 
excrements  digestible  or  absorbable  constituents  of  the  food,  such  as  muscle- 
fibres,  connective  tissues,  lumps  of  casein,  grains  of  starcli,  and  fat  wliich 
have  not  had  snlVicient  time  to  be  completely  digested  or  absorbed  in  the 
intestinal  tract.  In  addition  tlie  excrements  contain  indigestible  bodies, 
such  as  remains  of  plants,  keratin  substances,  nnclein,  and  others;  also 
form-elements  originating  from  the  mucous  coat  and  the  glands;  constit- 
uents of  the  diiferent  secretions,  such  as  mucin,  cholalic  acid,  dyslysin,  and 
cholesterin  (koprosterin  or  stercorin);  mineral  bodies  of  the  food  and  the 
secretions;  and,  lastly,  products  of  jjutrefaction  or  of  the  digestion,  such  as 
skatol,  indol,  volatile  fatty  acids,  lime,  and  magnesia  soaps.  Occasionally, 
also,  parasites  of  diiferent  kinds  occur;  and  lastly,  the  excrements  contain 
micro-organisms  of  various  kinds. 

That  tlie  mucous  membrane  of  tiie  intestine  by  its  secretion  and  by 
the  abundant  quantity  of  detached  epithelium  contributes  essentially  to 
tlie  formation  of  excrement  follows  from  the  discovery  first  made  by 
L.  Hermann  and  substantiated  by  others '  that  a  clean,  isolated  loop  of 
intestine  collects  material  similar  to  faeces.  Human  faeces  seems  to  consist 
in  greatest  port  of  intestinal  secretion  and  only  in  a  smaller  part  of  residue 
from  food.  Many  foods  produce  a  large  quantity  of  faeces  chiefly  by  causing 
an  abundant  secretion.' 

The  reaction  of  the  excrements  is  very  variable,  but  alkaline  in  man.  It 
is  often  acid  in  the  inner  part,  while  the  outer  layers  in  contact  with  the 
mucous  coat  have  an  alkaline  reaction.  In  nursing  infants  it  is  habitually 
acid  (Wegsctieider').  The  odor  is  perhaps  chiefly  due  to  skatol,  which 
was  first  found  in  the  excrements  by  Brieger,  and  so  named  by  him. 
Indol  and  other  substances  also  take  part  in  the  production  of  odor.  The 
color  is  ordinarily  light  or  dark  brown,  and  depends  above  .11  upon  the 
riature  of  the  food.  Medicinal  bodies  may  give  the  faeces  an  abnormal  color. 
The  excrements  are  colored  black  by  iron  and  bismuth,  yellow  by  rhubarb, 
and  green  by  calomel.  This  last-mentioned  color  was  formerly  accounted 
for  by  the  formation  of  a  little  mercury  sulphide,  but  now  it  is  said  that 
calomel  checks  the  pntrefaction  and  the  decomposition  of  the  bile-pigments, 
so  that  a  part  of  the  bile-pigments  passes  into  the  fnsces  as  biliverdin. 
According  to  Lesage  *  a  green  color  of  the  excrements  in  children  is  caused 
partly  by  biliverdin  and  partly  by  a  pigment  produced  from  a  bacillus. 

'  Herniami,  Pfillger's  Arch.,  Bd.  46.  See  also  Ehrenlbiil,  ibid.,  Bd.  48  ;  Berenstein, 
ibid.,  Bd.  .^)3  ;  Klccki.  Centralbl.  f.  Physiol.,  Bd.  7.  S.  736,  and  F.  Voit,  Zeitschr.  f. 
Biologie,  Bd.  29;  v.  Moiaczewski,  Zeitschr.  f.  pliysiol.  Chcm.,  Bd.  2.'>. 

*  In  regard  to  the  coustitutiou  of  faeces  with  various  foods  see  Hammerl,  Kermauner, 
Moeller,  aud  Prausuitz,  Zeitschr.  f.  Biologie,  Bd.  35. 

3  Sec  Mnly's  Jahresber.,  Bd.  6.  S.  182. 

*  Ibid.,  Bd.  18.  S.  336. 


H02  DIGESTION. 

Ill  the  yolk-yellow  or  greenish-yellow  excrements  of  nursing  infants  we  can 
detect  bilirubin.  Neither  bilirubin  nor  biliverdin  seems  to  exist  in  the 
excrements  of  mature  persons  under  normal  conditions.  On  the  contrary, 
we  find  STERCOBiLiN"  (Masius  and  VAiifLAiR),  which,  is  identical  with 
urobilin  (Jaffe  ').  Bilirubin  may  occur  in  pathological  cases  in  the  fseces  of 
mature  j)ersons.  It  has  been  observed  in  a  crystallized  state  (as  hgema- 
.toidin)  in  the  fseces  of  children  as  well  as  of  grown  persons  (Uffelmaxn", 
V.  Jaksch'). 

The  absence  of  bile  (acholic  fseces)  causes  the  excrements  to  have,  as 
above  stated,  a  gray  color,  due  to  large  quantities  of  fat;  this  may,  however, 
be  partly  attributed  to  the  absence  of  bile-pigments.  In  these  cases  a  large 
quantity  of  crystals  has  been  observed  (Gerhardt,  v.  Jaksch)  which  con- 
sist chiefly  of  magnesia  soaps  (Oesterlbn")  or  sodium  soaps  (Stadelmakn  °). 
Hemorrhage  in  the  upper  parts  of  the  digestive  tract  yields,  when  it  is  not 
very  abundant,  a  dark-brown  excrement,  due  to  hasmatin. 

ExCRETiN,  SO  named  by  Marcet,'*  is  a  crystalline  body  occurring  in  liumau  excre- 
ment, but  which,  according  to  Hoppe-Seyler,  is  perhaps  only  impure  cholesteriu 
(koprosteriu  or  stercorin  ?).  Excretolic  acid  is  the  name  given  by  Marcet  to  an  oily 
body  with  an  excrementiiious  odor. 

In  consideration  of  the  very  variable  composition  of  excrements  their 
quantitative  analyses  are  of  little  value  and  therefore  will  be  omitted. 

l^^conium  is  a  dark  brownish-green,  pitchy,  mostly  acid  mass  without 
any  strong  odor.  It  contains  greenish-colored  epithelium  cells,  cell-detritus, 
numerous  fat-globules,  and  cholesterin  plates.  The  amount  of  water  and 
solids  is  respectively  720-800  and  380-200  p.  m.  Among  the  solids  we  find 
mucin,  bile-pigments  and  bile-acids,  cholesterin,  fat,  soaps,  calcium  and 
magnesium  phosphates.  Sugar  and  lactic  acid,  albuminous  bodies  (?)  and 
peptones,  also  leucin  and  tyrosin  and  the  other  products  of  putrefaction 
occurring  in  the  intestine,  are  absent.  Meconium  may  contain  undecom- 
posed  tanrocholic  acid,  bilirubin  and  biliverdin,  bnt  it  does  not  contain  any 
stercobilin,  which  is  considered  as  proof  of  the  non-existence  of  putrefactive 
processes  in  the  digestive  tract  of  the  foetus. 

In  medico-legal  cases  it  is  sometimes  necessary  to  decide  whether  spots 
on  linen  or  other  substances  are  caused  by  meconium.  In  such  cases  we 
have  the  following  conditions:  The  spot  caused  by  meconium  has  a  br&wn- 
ish-green  color  and  can  be  easily  separated  from  the  material  because-  on 
account  of  the  ropy  property  of  the  meconium,  it  is  difRcult  to  wet  through. 
When  moistened  with  water  it  does  not  develop  any  special  odor,  but  on 
Nvarming  with  dilute  sulphuric  acid  it  has  a  somewhat  fetid  odor.     It  forms 

'  See  Chapter  VIII.,  on  the  bile,  and  Chapter  XV.  on  urobilin. 

*  Uffclmann,  Deutsch.  Arch,  f.  klin.  Med.,  Bd.  28  ;  v.  Jaksch,  Klinische  Diagnostik, 
4.  Aufl..  S   273. 

2  In  regard  to  fat  crystals  in  the  fseces  see  v.  Jaksch,  1.  c,  p.  274 

*  Annul,  de  chim.  et  de  phys.,  Tome  59. 


INTESTINAL    CONCREMENTS.  ^Oli 

•with  water  a  slimy,  greenisli-yellow  li(|uid  containiiif,'  brown  flukes.  'J'iie 
solution  gives  with  an  excess  of  acetic  acid  an  insoliiljle  precipitate  of  mucin; 
on  boiling  it  does  not  coagulate.  Tiie  filtered,  watery  extract  gives 
Gmklin's,  but  still  better  JIli'PEKt's,  reaction  for  bile-])igments.  The 
liquid  precipitated  by  an  excess  of  milk  of  lime  gives  a  nearly  colorless 
filtrate,  which  after  concentration  gives  Phttkxkoi'kr's  reaction. 

The  rontents  of  the  intestine  under  abnornitil  conditions  are  perhaps  less  ibe  subject  of 
chemifal  analysis  riiaii  of  an  inspection  and  microscopical  investigation  or  bacteriological 
exaniination.  On  this  account  tlie  iiuestion  as  to  the  properties  of  the  contents  of  the 
intestine  in  dillereut  diseases  cannot  be  thoroughly  treated  here. 

Appendix. 

Intestinal  Concrements. 

Calculi  occur  very  seldom  in  human  intestine  or  in  the  intestine  of 
carnivora,  but  they  are  quite  common  in  herbivora.  Foreign  bodies  or 
nndigested  residues  of  food  may,  when  for  some  reason  or  other  they  are 
retained  in  the  intestine  for  some  time,  become  incrusted  with  salts, 
especially  ammonium-magnesium  phosphate  or  magnesium  phosphate,  and 
these  salts  form  usually  the  chief  constituent  of  the  concrements.  In  man 
they  are  sometimes  oval  or  round,  yellow,  yellowish  gray,  or  brownish  gray, 
of  variable  size,  consisting  of  concentric  layers  and  containing  chiefly 
ammonium-magnesium  phosphate,  calcium  phosphate,  besides  a  small  quan- 
tity of  fat  or  pigment.  The  nucleus  ordinarily  consists  of  some  foreign 
body,  such  as  the  stone  of  a  fruit,  a  fragment  of  bone,  or  something  similar. 
In  those  countries  where  bread  made  from  oat-bran  is  an  important  food, 
we  often  find  in  the  large  intestine  balls  similar  to  the  so-called  hair-balla 
(see  below).  Such  calculi  contain  calcium  and  magnesium  phosphate 
(about  70,'^),  oat-bran  {l5-lSfo),  soaps  and  fat  (about  lOfo).  Concretions 
which  contain  very  much  (about  74:^)  fat  seldom  occur,  and  those  consist- 
ing of  fibrin  clots,  sinews,  or  pieces  of  meat  incrusted  with  phosphates  are 
also  rare. 

Intestinal  calculi  often  occur  in  animals,  especially  in  horses  fed  on 
bran.  These  calculi,  which  attain  a  very  large  size,  are  hard  and  heaw  (as 
much  as  8  kilos)  and  consist  in  great  part  of  concentric  layers  of  ammonium- 
magnesium  phosphate.  Another  variety  of  concrements  which  occurs  in 
horses  and  cattle  consists  of  gray-colored,  often  very  large,  but  relatively 
light  stones  which  contain  plant  residues  and  earthy  phosphates.  Stones 
of  a  third  variety  are  sometimes  cylindrical,  sometimes  spherical,  smooth, 
shining,  brownish  on  the  surface,  consisting  of  matted  hairs  and  plant- 
fibres,  and  termed  hair-halls.  The  so-called  "  ^egaoropila,"  which 
probably  originate  from  the  axtilopus  klpicapha,  belong  to  this  group, 
and  are  generally  considered  as  nothing  else  than  the  hair-balls  of  cattle. 

The  so-called  oriental  hczoar-stone  belongs  also  to  the  intestinnl  concre- 
ments,  and  probably  originates  from  the   intestinal  tract  of  the  capra. 


304  DIGESTION. 

^GAGRUS  and  aktilope  dorcas.  "We  may  have  two  varieties  of  bezoar- 
stones.  One  is  olive-green,  faintly  shining,  formed  of  concentric  layers. 
On  heating  it  melts  with  the  development  of  an  aromatic  odor.  It  contains 
as  chief  constituent  lithofellic  acid,  C^Jl^fi^^  which  is  related  to  cholalic 
acid,  and  besides  this  a  bile-acid,  lithobilic  acid.  The  others  are  nearly 
blackish  brown  or  dark  green,  very  glossy,  consisting  of  concentric  layers, 
and  do  not  melt  on  heating.  They  contain  as  chief  constituent  ellagig 
acid,  a  derivative  of  tannic  acid,  of  the  formula  0,^13,0^ ,  which  gives  a 
deep  blue  color  with  an  alcoholic  solution  of  ferric  chloride.  This  last- 
mentioned  bezoar-stone  originates,  to  all  appearances,  from  the  food  of  the 
animal. 

Ambergris  is  generally  considered  an  intestinal  concrement  of  the  sperm-whale.  Its 
chief  constituent  is  ambrain,  which  is  a  non-nitrogenous  substance  perliaps  related  to 
cholesterin.  Ambrain  is  insoluble  in  water  and  is  not  changed  by  boiling  alkalies.  It 
dissolves  in  alcohol,  ether,  and  oils. 


VI.   Absorption. 

The  problem  of  digestion  consists  in  part  in  separating  the  valuable  con- 
stituents of  the  food  from  the  useless  ones  and  dissolving  or  transforming 
them  into  forms  which  are  necessary  in  the  processes  of  absorption.  In 
discussing  the  absorption  processes  we  must  treat  of  the  form  into  which 
the  different  foods  are  transformed  before  absorption,  of  the  manner  in 
which  this  is  accomplished,  and,  lastly,  of  the  forces  which  act  in  these 
processes. 

Proteids  may  not  only  be  absorbed  from  the  intestine  as  albnmoses  and 
peptone,  but  also,  as  shown  by  the  earlier  investigations  of  Brucke,  Bauer 
and  YoiT,  Eichhorst,  Czerny  and  Latschenberger,  and  recently  by 
VoiT  and  Friedlaxder,'  as  non-peptonized  proteid.  In  the  researches 
of  the  last  two-mentioned  investigators  neither  casein  (as  milk)  nor  hydro- 
chloric acid  myosin  nor  acid  albuminate  (in  acid  solution)  was  absorbed, 
while,  on  the  contrary,  about  31,<  of  ovalbumin  or  seralbumin  and  69^  of 
alkali  albuminate  (dissolved  in  alkali)  were  absorbed.  Under  such  condi- 
tions the  question  arises,  to  what  extent  are  the  proteids  absorbed  as  pep- 
tone or  albumoses  or  in  other  forms  ? 

This  question  cannot  be  decisively  answered,  as  the  observations  on  this 
subject  are  contradictory.  In  investigating  the  stomachs  and  intestine  of 
dogs  ScHMiDT-MuLHEiM  found  that  the  quantity  of  peptone  (albumoses) 
in  tlie  intestinal  tract  was  considerably  greater  than  the  simply  dissolved 
proteid.     Other   experimenters,  such   as  Ellenberger   and  IIofmeister 

'  Brilcke,  Wieu,  Sitzungsber.,  Bd.  59  ;  Bauer  and  Voit,  Zeitschr.  f.  Biologic,  Bd.  5  ; 
Eichhorst,  PllUger'a  Arch.,  Bd.  4;  Czerny  and  Lalscheuberger,  Virchow's  Arch. 
Bd.  59  ;  Voit  and  Friedlander,  Zeitschr.  f.  Biologic,  Bd.  33. 


ABSOurriON.  305 

(experiments  on  pigs),  Ewald  and  Gumlk.ii'  (observations  on  man) 
found,  on  the  contr.irj,  only  very  insignificant  quantities  of  albumoses  and 
])eptones  iu  tiie  intestine  or  stoniacb.  If  the  albnmoses  and  peptones  are 
more  readily  absorbed  tban  tbe  otber  proteids  and  the  absorption  and  diges- 
tion in  the  stomach  rnn  parallel  (Sciimidt-Muliieim),  then  it  is  difficult  to 
draw  any  positive  conclusion  from  the  small  quantity  of  albnmoses  found. 

In  what  way  are  the  albumoses  and  peptones  absorbed,  and  liow  are  they 
conveyed  to  the  tisues  ?  The  generally  accepted  view  is  that  they  do  not 
pass  into  the  blood  through  the  lymphatics,  but  through  the  intestinal 
epithelium,  and  this  view  is  based  essentially  on  the  two  following  conditions. 
On  completely  isolating  the  chyle  from  the  blood  circulation,  the  proteid 
absorption  from  the  intestine  is  not  impaired  (Ludwig  and  Schmidt- 
MiJLUEiM);  and  on  a  diet  rich  in  proteid  the  quantity  thereof  in  the  chyle 
(in  man)  was  not  noticeably  increased  (Munk  and  Rosexstein).  Ascher 
and  Baubera  '  have  recently,  it  is  true,  shown  in  experiments  on  a  dog 
that  the  quantity  of  proteid  in  the  lymph  was  a  little  increased  after  par- 
taking of  abundance  of  proteid.  This  experiment  does  not  disprove  the 
assertion  of  Muxk  that  the  bood- vessels  form  nearly  the  exclusive  exit  of  the 
proteids  from  the  intestinal  tract. 

After  a  diet  rich  in  proteids  neither  albumoses  nor  peptone  are  found 
in  the  blood  or  the  chyle.  Nor  are  they  present  in  the  urine  ;  and  the 
absence  of  these  bodies  in  the  blood  after  digestion  cannot  be  exjilained  by 
the  statement  that  they,  like  the  peptone  (albumoses)  injected  subcutane- 
ously  or  directly  into  the  blood,  are  quickly  eliminated  through  the  kidneys 
(Plosz  and  Gyergyai,  Hofmeister,  Sciimidt-Mulheim ').  It  might  be 
supposed  that  the  peptone  (albumoses)  formed  in  digestion  are  retained  by 
the  liver,  and  that  this  is  the  reason  why  they  are  not  found  in  the  blood. 
Neumeister  has  investigated  the  portal  blood  of  rabbits  in  whose  stomachs 
large  quantities  of  albumoses  and  peptone  had  been  introduced,  without 
finding  traces  of  the  body  in  question.  He  has  also  shown  that  when  we 
supply  the  liver  of  a  dog  with  the  portal-blood  peptone  (ampho-peptone), 
this  is  not  retained  by  the  liver.  Shore  has  arrived  at  similar  results  in 
regard  to  the  importance  of  the  liver,  and  has  also  shown  that  the  spleen 
cannot  transform  peptone.  Peptone  seems  to  pass  neither  into  the  blood 
nor  the  chylous  vessels,  and   the  following  observation  of   Ludwig  and 


''  Schmidi-Mullieim,  Du  Bois-Reymond's  Arch.,  1879  ;  Ellenberger  and  Hofmeister, 
ibid.,  1800;  Ewulci  and  Gunilicb,  Berlin,  kliu.  Wochenschr.,  1890. 

'  Schmidt-MUllieini,  Du  Bois-Reymond's  Arch.,  1877  ;  Munk  and  Rosenstein,  Vir- 
chow's  Arch.,  Bd.  123;  Ascber  aud  Barbera,  Centralbl.  f.  Physiol.,  Bd.  11.  S.  403; 
Munk,  ihid.,  Bd.  11.  S.  585. 

'  Plosz  and  Gyergyai,  Pfluger's  Arch.,  Bd.  10  ;  Hofmeister,  Zeitschr.  f.  physiol. 
Obem.,  Bd.  5;  Schmidt-Miilheim,  Du  Bois-Reymond's  Arch.,  1880. 


306  DIGESTION. 

Salvioli'  bears  out  this  assamption.  These  investigators  introduced  a 
peptone  solution  into  a  double-ligatured,  isolated  piece  of  the  small  intes- 
tine, which  was  kept  alive  by  passing  defibrinated  blood  through  it,  and 
observed  that  the  peptone  disappeared  from  the  intestine,  but  that  the 
blood  passing  through  did  not  contain  any  peptone. 

All  observations  indicate  that  the  albumoses  and  peptone  are  trans- 
formed in  some  way  in  the  intestine  or  intestinal  wall;  and  as  the  albumoses 
can  replace  other  proteids  in  the  food  (see  Chapter  XVIII),  we  must  admit 
of  a  transformation  of  this  into  ordinary  proteid  in  the  intestine  or  in  the 
intestinal  wall. 

Certain  investigators,  such  as  v.  Ott,  Nadine  Popoff,  and  Julia 
Brixck,'  are  of  the  opinion  that  the  albumoses  and  peptone  of  gastric 
dio-estion  are  transformed  into  seralbumin  before  they  pass  into  the  walls  of 
the  digestive  tract.  This  transformation  is  brought  about  by  means  of  the 
epithelium  cells,  as  also  by  the  living  activity  of  a  fungus  called  by  Julia 
Brixck  micrococcus  restituens.  No  positive  proofs  have  been  presented  ta 
support  this  view. 

The  view  that  the  transformation  of  the  albumoses  and  peptone  takes- 
place  after  they  have  been  taken  up  by  the  mucous  membrane  has  better 
foundation.  The  observations  of  Hofmeister,'  according  to  whom  the 
walls  of  the  stomach  and  the  intestine  are  the  only  parts  of  the  body  in 
which  peptone  (albumoses)  occur  constantly  during  digestion,  and  also 
that  peptone  (at  the  temperature  of  the  body)  after  a  time  disappeared  from 
the  excised  but  apparently  still  living  mucous  coat  of  the  stomach,  confirm 

this. 

According  to  Hofmeistee,  the  leucocytes  of  the  adenoid  tissue,  which 
are  increased  during  digestion,  play  an  important  part.  They  may  take  up 
the  peptone  (albumoses)  and  be  the  means  of  transporting  them  to  the 
blood,  and  secondly  by  their  growth,  regeneration,  and  increase  may  stand 
in  close  relationship  to  the  transformation  and  assimalation  of  the  peptones. 
IIeidexiiaix,  who  considers  that  the  transformation  of  peptone  into 
proteid  in  the  mucous  membrane  is  positively  settled,  does  not  attribute  so 
great  an  importance  to  tliese  last  in  the  absorption  of  the  peptones  as 
HoFMEiSTEK,  chiefly  on  the  ground  of  comparative  estimation  of  the  quan- 
tity of  absorbed  peptones  and  leucocytes.     He  considers  it  most  probable 


>  Neumeister,  Sitzuugsber,  d.  pbys.-metl,  Gesellsch.  zii  Wiirzburg,  1889,  aud  Zeilschr 
f.  Biologic,  Bd.  24;  Sbore,  Journ.  of  Physiol.,  Vol.  11  ;  Salvioli,  Du  Bois-Reymond'a 
Arch.,  1880,  Suppl. 

*  V.  Ott,   Du  Bois-Reymoud's  Arch.,    1883  ;  Popoff,  Zeitschr.  f.  Biologic,   Bd.  25  ; 

Brinck,  ibid.,  S.  453. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  6,  and  Arch.  f.  exp.  Path.  u.  Pharm.,  Bdd.  19,  20, 

and  22. 


ABSORPTION  OF  A  LBV  MOSES  AND  PEPTONE.  30T 

tliat   the   reconversion    of   the   peptones  into   proteid  takes  place    in   the 
epithelinm  layers.     This  view  is  furtlier  corroborated  by  the  investigations 

of  SllOKE.' 

The  extent  of  the  proteid  absorption  is  dependent  essentially  upon  the 
kind  of  food  introdnced,  since  as  a  rale  the  protein  substances  from  an 
animal  source  are  much  more  completely  absorbed  than  from  a  vegetable 
source.  As  proof  of  this  we  give  the  following  observations:  In  his  experi- 
ments on  the  utilization  of  certain  foods  in  the  intestinal  canal  of  man 
RUHNER  found  that  with  an  altogether  animal  diet,  on  partaking  of  an 
average  of  738-88-4  grms.  fried  meat  or  948  grms.  eggs  per  day,  the  nitrogen 
deficit  with  the  excrement  was  only  2.5-2.8j^  of  the  total  introduced 
nitrogen.  With  a  strictly  milk  diet  the  results  were  somewhat  unfavorable, 
since  after  partaking  of  4100  grms.  milk  the  nitrogen  deficit  increased  to 
12^.  The  conditions  are  quite  different  with  vegetable  food,  as  shown  bj 
the  experiments  of  ^Ieter,  Rubxer,  IIultgren  and  Laxdergrex,  who 
made  experiments  with  various  kinds  of  rye  bread  and  found  that  the  loss 
of  nitrogen  through  the  fjeces  amounted  to  22-48^.  Experiments  with 
other  vegetable  foods,  and  also  the  investigations  of  Schuster,  Cramer, 
Meinert,  Mori,"  and  others  on  the  utilization  of  foods  with  mixed  diets, 
have  led  to  similar  results.  "With  the  exception  of  rice,  wheat  bread,  and 
certain  very  finely  divided  vegetable  foods,  it  is  found  in  general  that  the 
nitrogen  deficit  by  the  fseces  increases  with  a  larger  quantity  of  vegetable 
material  in  the  food. 

The  reason  for  this  is  manifold.  The  large  quantity  of  cellulose  frequenth' 
present  in  vegetable  foods  impedes  the  absorption  of  proteids.  The  greater 
irritation  produced  by  the  vegetable  food  itself  or  by  the  organic  acids 
formed  in  the  fermentation  in  the  intestinal  canal  causes  a  more  violent 
peristalsis  which  drives  the  contents  of  the  intestine  faster  than  otherwise 
along  the  intestinal  canal.  Another  and  most  important  reason  is  the  fact 
that  a  part  of  the  vegetable  protein  substances  seems  to  be  indigestible. 

In  speaking  of  the  functions  of  the  stomach  we  stated  that  after  the 
removal  or  excision  of  this  organ  an  abundant  digestion  and  absorption  of 
proteids  may  take  place.  It  is  therefore  of  interest  to  learn  how  the  diges- 
tion and  absorption  of  proteids  go  on  after  the  extirpation  of  the  second 
proteid-digesting  organ,  the  pancreas.  In  this  connection  we  have  the 
observations  on  animals  after  complete  or  partial  extirpation  of  the  gland 
by  Minkowski  and  Abelmanx,  Sandmeyer,  v.  Harley,  after  destroying 

'  Ileidenbain,  Pfluger's  Arch.,  Bd.  43;  Shore,  I.e. 

•  Riibner,  Zeitschr.  f.  Biologic,  Bd.  15  ;  Meyer,  t^td. ,  Bd.  7;  HuUgreu  and  Laudergreii, 
Noni.  ined.  Arch.,  Bd.  21:  Schuster,  in  Yoit"s  "Untersuch.  d.  Kost,"  etc.,  S.  142; 
Crauur  Zeitschr.  f.  physioI.  Cheni.,  Bd.  G;  Meiuert,  "  Ueber  MasseunUhrung,"  Berlin^ 
1885  ;  Kellner  and  Mori.  Zeitsclir.  f.  Biologic,  Bd.  25. 


308  digestion: 

the  gland  b}'  Rosenberg,  and  also  in  man  after  closing  the  pancreatic  duct 
by  Harlet,  Deucher.  '  In  all  these  different  cases  such  discrepant  figures 
have  been  obtained  for  the  utilization  of  theproteids — between  80^,  after  the 
apparently  complete  exclusion  of  pancreatic  juice  in  man  (Deucher),  and 
IS'^  after  extirpation  of  the  gland  in  dogs  (Harley) — that  we  can  hardly 
tlraw  any  clear  conception  as  to  the  extent  and  importance  of  the  trypsin 
digestion  in  the  intestine. 

The  carbohydrates  are,  it  seems,  chiefly  absorbed  as  monosaccharides. 
Glucose,  Ifevulose,  and  galactose  are  probably  absorbed  as  such.  The  two 
disaccharides,  cane-sugar  and  maltose,  ordinarily  undergo  an  inversion  in 
the  intestinal  tract  and  are  converted  into  glucose  and  Isevulose.  Lactose 
is  also,  at  least  in  certain  animals,  inverted  in  the  intestine.  Lactose, 
according  to  Voit  and  LusK,^  is  not  inverted  in  rabbits,  and  is  mainly 
absorbed  as  such  in  these  animals,  a  part  undergoing  lactic-acid  fermenta- 
tion. An  absorption  of  non-inverted  carbohydrates  is  not  improbable,  and 
according  to  Otto  and  v.  Meriistg'  the  portal  blood  contains  besides 
dextrose  a  dextrin-like  carbohydrate  after  a  carbohydrate  diet.  K  part  of 
the  carbohydrates  is  destroyed  by  fermentation  in  the  intestine,  with  the 
formation  of  lactic  and  acetic  acids. 

Tb4  different  varieties  of  sugars  are  absorbed  with  varying  degrees  of 
rapidity,  but  as  a  general  thing  absorption  occurs  very  quickly.  With 
experiments  on  dogs  Albertoxi  '  found  on  introducing  100  grms.  of  the 
sugar  that  during  the  first  hour  there  were  absorbed  60  grms.  dextrose, 
70-80  grms.  maltose  and  cane-sugar,  and  only  20-40  grms,  lactose.  He 
finds  that  lactose  is  relatively  more  readily  absorbed  from  dilute  solutions 
than  from  concentrated  ones. 

On  the  introduction  of  starch  even  in  very  considerable  quantities  into 
the  intestinal  tract  no  dextrose  passes  into  the  urine,  which  probably 
depends  in  this  case  upon  the  absorption  and  assimilation  and  the  slow 
saccharification  taking  place  simultaneously.  If,  on  the  contrary,  large 
quantities  of  sugar  are  introduced  at  one  time,  then  an  elimination  of  sugar 
by  the  urine  takes  place,  and  this  elimination  of  sugar  is  called  alimentary 
glycosuria.  In  these  cases  the  asimilation  of  the  sugar  and  the  absorp- 
tion do  not  occur  at  the  same  time,  hence  the  liver  and  the  remaining 
organs  do  not  have  the  necessary  time  to  fix  and  utilize  the  sugar.  This 
glycosuria  may  also  in  part  be  due  to  the  fact  that  the  introduction  of  con- 

'  Abelmann,  "  Ueber  die  Ausnlltzung  der  Nahningsstoffe  nach  Pankrensexstirpa- 
lion  "  (luaug.-Dissert,  Dorpat,  1890),  cited  from  Muly's  Jahresber.,  Bd.  29  ;  Saudmeyer, 
Zcitschr.  f.  Biologic,  Bd.  31;  Rosenberg,  PHiigcr's  Arch.,  Bd.  70;  Harley,  Jouru.  of 
Pathol,  and  Bacteriol.,  1895;  Deucher,  Correspond.  Blatt.  f.  Schweiz.  Aerzte,  Bd.  28. 

«  Zeitschr.  f.  Biologic,  Bd.  28. 

'  Otto,  see  Maly's  Jahresber.,  Bd.  17  ;  v.  Mcring,  Dii  Bois-Reymond's  Arch.,  1877. 

•*  ManiSre  do  se  comporter  des  snores,  etc.,  Arcli.  ital.  de  Biol.,  Tome  15. 


ABsonrnoy  of  (•AnnoiiYDiiAiES.  309 

siderable  quantities  of  sugar  forces  the  sugar  in  absorjjtion  not  only  in  the 
ordinary  way  tlirough  the  blood-vessels  to  the  liver  (^ee  below),  but  also  in 
part  by  passing  into  the  blood  circulation  through  the  lymphatic  vessels, 
evading  the  liver. 

That  quantity  of  sugar  to  which  wo  must  raise  the  sugar  partaken  of  to 
produce  an  alimentary  glycosuria  gives,  according  to  IIof.mkistek,'  the 
ass  i  III  Hut  ion  limit  for  that  same  sugar.  This  limit  is  ditterent  for  various 
kinds  of  sugar;  and  it  also  varies  for  the  same  sugar  not  only  \\\  ditlerent 
animals,  but  also  for  different  members  of  the  same  species,  as  also  for  the 
same  individual  under  dilTerent  circumstances.  In  general  we  can  say  that 
in  regard  to  the  ordinary  varieties  of  sugar,  such  as  dextrose,  laevulose, 
cane-sugar,  maltose,  and  lactose,  the  assimilation  limit  is  highest  for 
dextrose  and  lowest  for  lactose.  We  must  admit  that  with  an  overabundant 
quantity  of  sugars  in  the  intestinal  tract  the  disaccharides?  do  not  have 
sufficient  time  for  their  complete  inversion;  hence  it -is  not  remarkable  that 
disaccharides  have  been  found  in  the  urine  in  cases  of  alimentary  glycosuria." 

From  the  investigations  of  Ludwig  and  Y.  jMkking  and  others  we  learn 
how  the  sugars  pass  into  the  blood-stream,  namely,  that  they  as  well  as 
bodies  soluble  in  water  do  not  ordinarily  pass  over  into  the  chylous  vessels 
in  measurable  quantities,  but  are  in  greatest  part  taken  up  by  the  blood  in 
the  capillaries  of  the  villi  and  in  this  way  jiass  into  the  mass  of  the  blood. 
These  investigations  have  been  confirmed  by  observations  of  I.  Munk  and 
EosENSTEix  '  on  human  beings. 

The  reason  why  the  sugar  and  otlier  soluble  bodies  do  not  pass  over  into 
the  chylous  vessels  in  appreciable  quantity  is,  according  to  IIeidexhain,* 
to  be  found  in  the  anatomical  conditions,  in  the  arrangement  of  the  capil- 
laries close  under  the  layer  of  epithelium.  Ordinarily  these  capillaries  find 
the  necessary  time  for  the  taking  up  of  the  water  and  the  solids  dissolved 
in  it.  But  when  a  large  quantity  of  liquid,  such  as  a  sugar  solution,  is 
introduced  into  the  intestine  at  once,  this  is  not  possible,  and  in  these  cases 
a  part  of  the  dissolved  bodies  passes  into  the  chylous  vessels  and  the  thoracic 
duct  (GixsHEHG  and  Roiimann '). 

The  introduction  of  larger  quantities  of  sugar  into  the  intestine  at  one 
time  can  readily  cause  a  disturbance  with  diarrhoeal  evacuations  of  the 
intestine.  If  the  carbohydrate  is  introduced  in  the  form  of  starch,  then 
very  large  quantities  may  be  absorbed  without  causing  any  disturbance,  and 


'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bdd.  25  and  26. 

*  For  the  literature  in  regard  to  the  passage  of  various  liinds  of  sugars  into  the  urine 
see  C.  Volt,  Ueber  die  Qlykogenbildung,  Zeitschr.  f.  Biologie,  Bd.  28,  and  F.  Voit,  foot- 
note 3,  page  216 

'  V.  Mering.  Dii  Bois-Reyniond's  Arcli.,  1877  ;  Munk  and  Roseustein,  1.  c. 

*  Pfla-rer's  Arch..  Bd.  4:i,  Suppl. 

'  Ginsberg,  Pfliiger's  Arch.,  Bd.  44  ;  ROhuianu,  ihid.,  Bd.  41. 


310  DIGESTION. 

the  absorption  may  be  very  complete.  Eubxer  fonnd  the  following:  On 
partaking  508-670  grms.  carbohydrates,  as  wheat  bread,  per  day  the  part  not 
absorbed  amounted  to  only  0.8-2.6^.  For  peas,  where  357-588  grms.  were 
eaten,  the  loss  was  3.6-7,^,  and  for  potatoes  (718  grms.)  7.6,'^,  Coxstax- 
TixiDi  fonnd  on  partaking  367-380  grms.  carbohydrates,  chiefly  as  potatoes, 
a  loss  of  only  0.4-0.7^.  In  the  experiments  of  Rubxer,  as  also  of 
IIuLTGREX  and  Landergrex,'  with  rye  bread  the  utilization  of  carbo- 
hydrates "was  less  complete,  altljough  the  loss  in  a  few  cases  rose  even  to 
10^4-10.9^.  It  at  least  follows  from  the  experiments  made  thus  far  that 
man  can  absorb  more  than  500  grms.  carbohydrates  per  diem  without 
difficnlty. 

We  generally  consider  the  pancreas  as  the  most  important  organ  in  the 
digestion  and  absorption  of  amylaceous  bodies,  and  it  is  a  question  how 
these  bodies  are  absorbed  after  the  extirpation  of  the  pancreas.  As  on  the 
absorption  of  proteids,  so  also  on  the  absorption  of  starch  the  observations 
have  given  variable  results.  In  certain  cases  the  absorption  was  nearly 
nUi  while  in  others  it  was,  on  the  contrary,  rather  im]3aired,  and  with 
dogs  devoid  of  pancreas  it  has  been  found  that  the  starch  partaken  was 
decreased  50^  (Eosexberg,  Cavazzaxi"). 

Emulsification  seems  to  be  of  the  greatest  importance  in  the  absorption 
of  fats/  and  this  emulsion  occurs  in  the  chyle  on  the  introduction  into  the 
intestine  of  not  only  neutral  fats,  but  also  of  fatty  acids.  The  fatty  acids 
do  not  exist  as  such  in  the  emulsified  fat  of  the  chyle.  The  investigations 
of  I.  MujSTK,  later  confirmed  by  others,'  have  shown  that  the  fatty  acids 
undergo  in  great  part  a  synthesis  into  neutral  fats  in  the  walls  of  the  intes- 
tine, and  carried  as  such  by  the  stream  of  chyle  into  the  blood. 

The  assumption  that  the  fat  is  absorbed  chiefly  as  an  emulsion  is  partly 
based  on  the  abundance  of  emulsified  fat  in  the  chyle  after  feeding  with  fat, 
and  partly  on  the  fact  that  a  fat  emulsion  is  often  found  in  the  intestine 
after  such  food.  As  an  abundant  cleavage  of  neutral  fats  occurs  in  the 
intestinal  canal,  and  also  as  the  fatty  acids  do  not  occur  in  the  chyle  as  such, 
but  as  emulsified  fat  after  a  synthesis  with  glycerin  into  neutral  fats,  it  is 
to  be  doubted  whether  the  emulsified  fat  of  the  chyle  originates  from  an 
absorption  of  emulsified  fat  in  the  intestine  or  from  a  subsequent  emulsifi- 
cation of  neutral  fats  formed  synthetically.  This  doubt  has  greater 
warrant  in  that  Frank  *  has  shown  that  the  fatty  acid  ethyl  ester  is  abun- 

'  liubner,  Zeitscbr.  f.  Biologie,  Bdd.  15  and  19;  Constantinidi,  ibid.,  Bd.  23  ;  Ilult- 
gren  and  Landergreu,  1.  c. 

-  Cavazzani,  Centralbl.  f.  Physiol.,  Bd.  7.     See  also  foot-note  1,  page  308. 

^  Munk,  Virchow's  Arch.,  Bd.  80.  See  also  v.  AValther,  Dii  Bois-Reymond's  Arch., 
1890;  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  21  ;  Frank,  Zeitschr.  f.  Biologie. 
Bd.  36. 

*  Zeitschr.  f.  Biologie,  Bd.  36. 


ABSOliPTIOy  GF  FATS.  311 

tiantly  taken  np  by  the  chyle  from  the  intestine,  not  as  snch,  bnt  as  split-off 
fatty  acids  from  which  then  the  neutral  emulsitieJ  fats  of  the  chyle  are 
formed. 

The  assumption  of  an  absorption  of  the  futs  as  an  emulsion  contnidicls 
the  fact  as  above  stated,  page  "iO'-i,  that  an  emulsion  produced  by  means  of 
soaps  is  only  permanent  in  an  alkaline  liquid  and  therefore  it  is  hardly 
possible  for  such  an  emulsion  to  form  in  the  intestine  as  long  as  it  is  acid. 
It  is  nevertheless  possible  that  the  pancreatic  juice  by  means  of  the  proteid 
it  contains  may  have  an  emulsifying  action  even  in  an  acid  reaction 
(Kuhn'e');  on  the  other  hand  we  know  of  cases  (Ludwig  and  Caj^h'  and 
others)  (in  dogs  after  partaking  food  rich  in  fat)  iii  which  an  absorption  of 
fat  took  place  from  the  acid  intestinal  contents  despite  the  absence  of  an 
emulsion  in  the  intestiuf  In  order  to  explain  such  a  case  it  has  been  as- 
sumed that  the  emulsilication  took  place  first  on  the  surface  of  the  intesti- 
nal mucosa  by  the  action  of  its  alkaline  secretion.  Moore  and  Rockwood  * 
give  anotlier  explanation.  According  to  them,  the  absorption  of  fat  from  the 
acid  intestinal  contents  is  essentially  due  to  the  solvent  action  of  the  bile 
for  free  fatty  acids.  The  neutral  fats  are  split  and  the  free  fatty  acids  are 
in  part  alisorbed,  dissolved  as  such  by  the  bile,  and  in  part  combined  with 
alkalies,  forming  soaps.  Xeutral  fats  are  regenerated  from  the  fatty  acids, 
and  the  alkali  set  free  from  the  soaps  is  secreted  back  again  into  the  intes- 
tine and  used  for  the  re-formation  of  soaps.  This  view,  which  stands 
in  accord  with  several  observations,  is  worthy  of  the  greatest  consideration. 
At  all  events  it  is  certain  that  the  greatest  part  of  the  fats — according  to 
certain  investigators  all  neutral  fats — is  split  in  the  intestine,  and  also  that 
the  formation  of  soaps  is  one  form  of  the  absorption  of  the  fats. 

The  next  question  is  whether  all  the  fat  or  the  greater  part  of  the  same 
passes  to  the  blood  through  the  lymphatics  and  the  thoracic  duct.  Accord- 
ing to  the  researches  of  Walther  and  Frank  *  on  dogs,  it  seems  that  only 
a  small  part  of  the  fats,  or  at  least  of  the  fatty  acids,  fed,  passes  into  the 
chylous  vessels;  but  these  observations  cati  hardly  be  applied  to  the  absorp- 
tion of  neutral  fats,  or  to  the  absorption  in  num  under  normal  circumstances. 
MuNK  and  Rosexsteix  '  in  their  investigations  on  a  girl  with  lymph  fistula 
found  CiOi;  of  the  fat  partaken  of  in  the  chyle,  and  of  the  total  quantity  of 
fat  in  the  chyle  only  ^-b'i  existed  as  soaps.  On  feeding  with  a  foreign 
fatty  acid,  such  as  erncic  acid,  they  found  37'^  of  the  introduced  body  as 
neutral  fat  in  the  chyle. 

The  completeness  with  which  fats  are  absorbed  depends,  under  normal 

'  Lehrbuch  d.  pliysiol.  Cheiii..  S.  122. 
'  Du  Bois-Reymoiul's  Arch.,  ISSO. 

*  Journ.  of  Pliysiol.,  Vol.  21. 

*  "SVallher,  1.  c;  Frank,  Du  Bois-Reymond's  Arch.,  1893. 
»  Virchow's  Arch.,  Bd.  123. 


312  DIGESTION. 

conditions,  essentially  upon  the  kind  of  fat.  In  this  regard  we  know, 
especially  from  the  investigations  of  Mujstk  and  Aknschink,'  that  the- 
varieties  of  fat  with  high  melting-points,  sach  as  mutton  tallow  and 
especially  stearin,  are  not  so  completely  absorbed  as  the  fats  with  low  melt- 
ing-points, such  as  hog-  and  goose-fat,  olive-oil,  etc.  The  kind  of  fat  also 
has  an  influence  upon  the  rapidity  of  absorption,  as  Mukk  and  Eosexsteik 
found  that  solid  mutton-fat  was  absorbed  more  slowly  than  fluid  lipanin. 
The  extent  of  absorption  in  the  intestinal  tract  is,  under  physiological  con- 
ditions, very  considerable.  In  a  case  of  a  dog  investigated  by  Voit  he  found 
that  out  of  350  grms.  of  fat  (butter)  partaken,  346  grms.  were  absorbed  in 
the  intestinal  canal,  and  according  to  the  investigations  of  Rubber'  the 
human  intestine  can  absorb  over  300  grms.  fat  per  diem.  The  fats  are, 
according  to  Rubner,  much  more  completely  absorbed  when  free,  in  the 
form  of  butter  or  lard,  than  when  enclosed  in  the  cell-membranes,  as  in 
bacon. 

Claude  Bernard  showed  long  ago  with  experiments  on  rabbits  in 
which  the  choledochus  duct  was  introduced  in  the  small  intestine  above  the 
pancreatic  duct,  that  after  food  rich  in  fats  the  chylous  vessels  of  the  intes- 
tine above  the  pancreas  passages  were  transparent,  while  below  they  were 
milk-white,  and  also  that  the  bile  can  produce  an  absorption  of  the  emulsi- 
fied fat/without  the  pancreatic  juice.  Dastre'  has  performed  the  reverse 
experiment  on  dogs,  namely,  he  tied  the  choledochus  duct  and  adjusted  a 
biliary  fistula  so  that  the  bile  flowed  into  the  intestine  below  the  mouth  of 
the  pancreatic  passages.  On  killing  the  animal  after  a  meal  rich  in  fat  the 
chylous  vessels  were  flrst  found  milk-white  below  the  discharge  of  the  biliary 
fistula.  From  this  Dastre  draws  the  conclusion  that  a  combined  action 
of  the  bile  and  pancreatic  juice  is  important  in  the  absorption  of  fats— a 
conclusion  which  stands  in  good  accord  wtih  the  experience  of  many  others. 

Through  numerous  observations  of  many  investigators,  such  as  Bidder 
and  Schmidt,  Voit,  Rohmafn",  Fr.  Muller,  I.  Muxk,'  and  others,  it  has 
been  shown  that  the  exclusion  of  the  bile  from  the  intestinal  tract  diminishes 
the  absorption  of  fat  to  such  an  extent  that  only  \  to  about  ^  of  the 
quantity  of  fat  ordinarily  absorbed  undergoes  absorption.  In  icterus  with 
entire  exclusion  of  the  bile  a  considerable  decrease  in  the  absorption  of  fat 
is  noticed.  As  under  normal  conditions,  so  also  in  the  absence  of  bile  in 
the  intestine  the  more  readily  melting  parts  of  the  fats  are  more  completely 
absorbed  than  those  which  have  a  high  melting-point.  I.  MuxK  found  in 
his  experiments  with  lard  and  mutton  tallow  on  dogs  that  the  absorption  of 

'  Munk,  Virchow'pi  Arch..  Bdd.  80  and  95  ;  Avnschink,  Zeitschr.  f.  Biologic,  Bd.  26. 
'  Voil,  ihid.,  Bd.  9  ;  Itubiier,  ibid.,  Bd.  15. 
»  Arch,  de  Physiol.  (5).  Tome  2. 

*  P.  IVIiillcr,  Sitznngsber.  de  phys.-med.  Gesellsch.  zu  Wurzburg,  1885;  I.  Muuk, 
Virchovv's  Arch.,  Bd.  122.     See  also  foot-note  4,  piige  298,  and  foot-note  1,  page  299. 


ABSORPTION   OF  FATS.  313 

the  liigh  melting  tiillow  was  reduced  twice  as  miicli  as  tlie  lard  on  the 
exchisioa  of  the  bile  from  the  intestine. 

We  also  learn  from  the  investigations  of  Rohmann  and  I.  Munk  that 
in  the  absence  of  bile  the  relationship  between  fatty  acids  and  neutral  fats 
is  changed,  namely,  about  80-00''^  of  the  fat  existing  in  the  faeces  consists 
of  fatty  acid,  while  under  normal  conditions  the  faeces  contain  1  part 
neutral  fat  to  about  'I-IX  parts  free  fatty  acids.  We  cannot  positively  state 
how  this  relatively  increased  quantity  of  fatty  acids  in  the  fat  of  tb.e  fa.'ces 
is  produced  on  the  exclusion  of  the  bile  from  the  intestine.  According  to 
the  investigations  of  ]\Iuxiv  it  does  not  in  the  least  depend  upon  the  fact 
that  the  fatty  acids  are  less  readily  absorbed  than  the  neutral  fats,  for  just 
the  reverse  is  the  case. 

There  is  no  doubt  that  the  bile  is  of  great  importance  in  the  absorption 
of  fats.  Still  there  is  also  no  doubt  that  rather  considerable  ».(Uautities  of 
fat  may  be  absorbed  from  the  intestine  in  the  absence  of  bile.  What  relation 
does  the  pancreatic  juice  bear  to  this  question  ? 

Upon  this  point  a  rather  large  number  of  observations  on  animals  have 
been  made  by  Abelmann  and  Minkowski,  Sandmeyer,  Harley,  Rosen- 
BEKG,  IIedon  and  Yille,  and  also  on  man  by  Fk.  ^Muller  aiul  Deuciier.' 
In  all  these  investigations  a  more  or  less  diminished  absorption  of  fat 
was  observed  after  the  extirpation  or  destruction  of  the  gland,  or  the 
exclusion  of  the  juice  from  the  intestine.  The  results  are  very  diverse  as 
to  the  extent  of  this  diminution,  as  in  certain  cases  no  absorption  of  fat  was 
observed,  while,  on  the  contrary,  a  considerable  absorption  was  noted  in 
the  same  class  of  animal  (dog)  and  even  in  the  same  animal.  According 
to  Minkowski  and  Abelmaxn,  after  the  total  extirpation  of  the  pancreas 
the  fat  of  the  food  introduced  is  not  absorbed  at  all,  with  the  exception  of 
milk,  of  which  28-53^  of  its  fat  is  absorbed.  Other  investigators  have 
obtained  other  results,  and  IIarley  has  observed  a  case  where  in  a  dog  an 
absorption  of  only  4^  of  the  milk-fat,  or,  on  the  complete  exclusion  of  in- 
testinal bacteria,  even  no  absorption,  took  jilace.  The  conditions  may  be 
somewhat  different  in  the  different  cases;  but  it  is  certain  that  the  absence 
of  pancreatic  juice  from  the  intestine  essentially  affects  the  fat  absorption. 
It  is  also  just  as  cert:. in  that  the  absorption  of  fat  is  most  abundant  in  the 
simultaneous  presence  of  bile  as  well  as  pancreatic  juice  in  the  intestine. 
A  little  fat  may  still  be  absorbed  even  in  the  absence  of  these  two  fluids 
(IIedox  and  Ville).  Cunningham'''  has  given  further  proof  that  a  slight 
absorption  of  fat  takes  place  (even  when  introduced  as  oil  and  not  as  milk) 

'  MQlIer,  "Uiiter.  liber  den  Icterus,"  Zeitsclir.  f.  kliu.  Med.,  Bd.  12;  Hedou  and 
Ville,  Arch,  de  Physiol.  (5),  Tome  9;  Harley,  Jouni.  of  Pbysiol.,  Vol.  18,  Journ.  of 
Pathol,  and  Bactcriol.,  1895,  aud  Proceed.  Roy.  Soc,  Vol.  61.  lu  regard  to  the  other 
authors  see  foot-note  1,  page  308. 

5  Journ.  of  Physiol.,  Vol.  23. 


^14  DIGESTION. 

on  the  complete  exclusion  of  the  bile  as  well  as  the  pancreatic  juice  from 
the  intestine. 

The  reason  why  tlie  fat  absorption  is  diminished  in  the  absence  of  bile 
or  pancreatic  juice  from  the  intestine  is  not  clear.  The  most  ordinary 
view  is,  that  to  form  an  emulsion  of  the  fat  a  part  of  the  same  mast  be  split 
by  the  action  of  the  pancreatic  juice,  and  that  this  action  is  accelerated  by 
the  bile.  It  must  also  be  added  that  the  bile  is  a  good  solvent  for  the  fatty 
acids  set  free.  The  reason  for  the  imperfect  absorption  of  fat  is  not  to  be 
sought  in  the  diminished  cleavage  of  neutral  fats,  as  the  non-absorbed  fat  of 
the  f feces  consists,  on  the  exclusion  of  bile  and  pancreatic  juice  (Minkowski 
and  Abelmakn",  Harlet,  Hedon"  and  Ville,  Deucher),  chiefly  of  free 
fatty  acids.  A  still  unknown  change  caused  by  micro-organisms  or  other- 
wise may  produce  a  cleavage  of  the  fat  in  these  cases.  The  imperfect  fat 
absorption  after  the  extirpation  of  the  pancreas  can  possibly  be  explained 
by  the  removal  of  a  considerable  part  of  the  alkalies  necessary  for  the 
formation  of  the  emulsion  and  for  the  solution  of  the  fatty  acids,  but  as 
Sandmeyer  found  in  pancreasless  dogs  that  the  fat  absorption  was  raised 
by  giving  choj^ped  pancreas  with  the  fat,  this  can  hardly  be  a  sufficient 
explanation.  It  has  also  been  assumed  that  it  is  chiefly  the  proteids  in  the 
pancreatic  juice  which  cause  the  emulsification,  and  that  the  diminished  fat 
absorpxion  after  extirpation  of  the  pancreas  is  explained  in  this  way.  The 
reasons  suggested  are  nevertheless  insufficient,  but  we  must  not  forget  the 
fact  that  an  abundant  absorption  of  fat  is  also  possible  in  the  absence  of  an 
emulsion  in  the  intestine. 

Harley  '  has  performed  a  partial  extirpation  of  the  large  intestine,  and 
also  a  total  extirpation.  The  total  extirpation  caused  a  considerable 
increase  in  the  fasces,  chiefly  because  of  a  fivefold  increase  of  water.  Fat 
and  carbohydrates  were  normally  absorbed.  The  absorption  of  proteids,  on 
the  contrary,  was  considerably  decreased  to  only  84^,  as  compared  with 
QS-OS^^  in  normal  dogs.  In  the  faeces,  after  extirpation,  no  urobilin  or  only 
traces  were  found,  while  the  bile-pigments  existed  to  a  great  extent. 

The  soluble  salts  are  also  absorbed  with  the  water.  The  proteids,  which 
can  dissolve  a  considerable  quantity  of  salts,  such  as  earthy  phosphates, 
which  are  otherwise  insoluble  in  alkaline  water,  are  of  great  importance  in 
the  absorption  of  such  salts. 

The  soluble  constituents  of  the  digestive  secretions  may,  like  other  dis- 
solved bodies,  be  absorbed,  as  is  demonstrated  by  the  passage  of  peptone 
into  urine;  the  enzymes  may  also  be  absorbed.  The  occurrence  of  urobilin 
in  urine  attests  the  absorption  of  the  bile-constituents  under  physiological 
conditions  despite  the  fact  that  the  occurrence  of  very  small  traces  of 
bile-acids   in  the  urine  is  disputed.     The  absorption  of  bile-acids  by  the 

'  Proceed.  Roy.  Soc,  Vol.  64. 


AB80UPT10N  OF  FATS.  315 

intestine  seems  to  bo  positively  proved  by  other  observations.  Tap- 
I'KINEK  '  introduced  n  solution  of  bile-salts  of  a  known  concentration  into 
an  intestinal  knot,  and  after  a  time  investigated  the  contents.  He  found 
that  in  the  jejunum  and  the  ileum,  but  not  in  tlie  duodenum,  an  absorption 
of  bile-acids  took  place,  and  further  that  of  the  two  bile-acids  only  the 
glycocholic  acid  was  absorbed  in  the  jejnnum.  Further,  Schiff  long  ago 
expressed  the  opinion  that  bile  undergoes  an  intermediate  circulation,  in 
such  wise  that  it  is  absoi'bed  from  the  intestine,  then  carried  to  the  liver  by 
the  blood,  and  lastly  eliminated  from  the  blood  by  this  organ.  Although 
this  view  has  met  with  some  opposition,  'still  its  correctness  seems  to  be 
established  by  the  researches  of  various  investigators,  and  more  recently  by 
Prevost  and  Binet,  as  also  and  specially  by  Stadelmann  and  his  pupils.' 
After  the  introduction  of  foreign  bile  into  the  intestine  of  an  animal  the 
foreign  bile-acids  appear  again  in  the  secreted  bile. 

Little  is  known  concerning  the  forces  taking  pari  in  absorption. 
Osmosis  and  fdtration  were  formerly  considered  as  the  most  important 
factors.  Later  we  have  become  more  and  more  inclined  to  IIoppe-Seyler's  ' 
views,  namely,  that  absorption  is  in  great  part  a  process  connected  with 
the  vital  properties  of  the  cells.  This  view  has  been  strongly  emphasized 
by  IIeideniiaix,  based  especially  on  his  own  observations,  but  also  on  those 
of  his  pupils.*  According  to  IIeidenhain  a  special  physiological  motive 
force  exists  in  the  cells  besides  which,  under  certain  circumstances  osmosis 
may  act,  but  wliich,  under  other  circumstances,  may  bring  about  an  ab- 
sorption with  the  complete  exclusion  of  osmosis.  It  would  lead  us  too  far 
to  go  deeper  into  this  subject.  In  regard  to  these  questions  we  must  refer 
the  reader  to  the  special  works  and  to  text-books  on  physiology. 


'  Wieii.  Sitzungsber.,  Bd.  77. 

'  Scliiff,  Pdugers  Arch.,  Bd.  3;  Prevost  and  Biuet,  Compt.  reud.,  Tome,  106; 
Stadelmann,  see  foot-note  2,  page  225. 

^Physiol.  Chem..  S.  348. 

••  Heideuliain,  PHiigcr's  Arch..  Bdd.  43  and  45  ;  with  his  pupils:  ROlimann,  ibid., 
Bd.  41  ;  Gumilewski,  ibid.,  Bd.  39.  See  also  Hamburger,  Du  Boia-Reymonu's  Arch., 
1896,  and  O.  Cohnheim,  Zeitschr.  f.  Biologic,  Bd.  36. 


CHAPTER   X. 

TISSUES   OF   THE   CONNECTIVE   SUBSTANCE. 

I.  The   Connective  Tissues. 

The  form-elements  of  the  typical  connective  tissues  are  cells  of  various 
kinds,  of  a  not  very  well  known  chemical  composition,  and  gelatin-yielding 
fibrils,  which,  like  the  cells,  are  imbedded  in  an  interstitial  or  intracellular 
substance.  The  fibrils  consist  of  collagen.  The  interstitial  substance  con- 
tains chiefly  imiciti  besides  serglobulin  and  seralbumin,  which  occur  in  the 
parenchymatous  fluid  (Loebisch  '). 

The  connective  tissue  also  often  contains  fibres  or  formations  consisting 
of  elastin,  sometimes  in  such  great  quantities  that  the  connective  tissue 
is  transformed  into  elastic  tissue.  A  third  variety  of  fibres,  the  reticular 
fibred,  also  occur,  and  according  to  Siegfried  these  consist  of  reticulin. 

^li  finely  divided  tendons  are  extracted  in  cold  water,  the  albuminous 
bodies  soluble  in  the  nutritive  fluid  in  addition  to  a  little  mucin  are  dissolved. 
If  the  residue  is  extracted  with  half-saturated  lime-water,  then  the  mucin  is 
dissolved  and  may  be  precipitated  from  the  filtered  extract  by  saturating 
with  acetic  acid.  The  digested  residue  contains  the  fibrils  of  the  connective 
tissue  together  with  the  cells  and  the  elastic  substance. 

The  fibrils  of  the  connective  tissue  are  elastic  and  swell  slightly  in  water, 
somewhat  more  in  dilute  alkalies  or  in  ac.etic  acid.  On  the  other  hand, 
they  shrink  by  the  action  of  certain  metallic  salts,  such  as  ferrous  sulphate 
or  mercuric  chloride,  and  tannic  acid,  which  forms  an  insoluble  combination 
with  the  collagen.  Among  these  combinations,  which  prevent  putrefaction 
of  the  collagen,  that  with  tannic  acid  has  been  found  of  the  greatest  techni- 
cal importance  in  the  jireparation  of  leather.  In  regard  to  tendon  mucin 
see  page  45,  and  in  regard  to  collagen,  gelatin,  elastin,  and  reticulin,  pages 
53-58. 

The  tissues  described  under  the  names  mucous  or  gelatinous  tissues  are 
characterized  more  by  their  physical  than  their  chemical  properties  and  have 
been  but  little  studied.  So  much,  however,  is  known,  that  the  mucous  or 
gelatinous  tissues  contain,  at  least  in  certain  cases,  as  in  the  &csi\ep\xse,  no 
mucin. 

•Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 

316 


CAIiTILAGK.  317 

The  umbilical  cord  is  the  most  accessible  material  for  the  investigation 
of  the  clicmical  constituents  of  the  gelatinous  tissues.  Tiie  mucin  occurring 
therein  lias  been  described  on  page  45.  C.  Tii.  Mounek  '  has  found  a 
mucoid  in  the  vitreous  liunior  which  contains  12.27^  nitrogen  aiid  1-19^ 
sulpliur. 

Young  connective  tissue  is  riclier  in  mucin  than  old.  Halliburton' 
found  an  average  of  7.GG  p.m.  mucin  in  the  skin  of  very  young  children 
and  only  3.85  p.m.  in  the  skin  of  adults.  In  so-called  myxoedema,  in 
which  a  reformation  of  the  connective  tissue  of  the  skin  takes  place,  the 
quantity  of  mucin  is  also  increased. 

II.  Cartilage. 

Cartilaginous  tissue  consists  of  cells  and  an  originally  hyaline  matrix, 
which,  however,  may  become  changed  in  such  wise  that  there  appears  in  it  a 
network  of  elastic  fibres  or  connective-tissue  fibrils. 

Those  cells  that  oifer  great  resistance  to  the  action  of  alkalies  and 
acids  have  not  been  carefully  studied.  According  to  former  views,  the 
matrix  was  considered  as  consisting  of  a  body  analogous  to  collagen,  so- 
called  cliomlrigen.  The  recent  investigations  of  Mokochowetz  and  others, 
but  especially  those  of  C.  Th.  Morner,^  have  shown  that  the  matrix 
of  the  cartilage  consists  of  a  mixture  of  collagen  with  other  bodies. 

The  tracheal,  thyroideal,  cricoidal,  and  arytenoidal  cartilages  of  full- 
grown  cattle  contain,  according  to  Morner,  four  constituents  in  the 
matrix,  namely,  chondromucoid^  cho)idroitin-s7ilphuric  acid,  collagen,  and 
an  (dhuminoid. 

Chondromucoid.  This  body,  according  to  Morner,  has  the  composition 
C  47.30,  II  G.42,  N  12.58,  S  2.42,  0  31.28,'^.  Sulphur  is  in  part  loosely 
combined  and  may  be  split  off  by  the  action  of  alkalies,  and  a  part  separates 
as  sulphuric  acid  when  boiled  Avith  hydrochloric  acid.  Chondromucoid  is 
decomposed  by  dilute  alkalies  and  yields  alkali  albuminate,  peptone  sub- 
stances, chondroitiu-sulphuric  acid,  alkali  sulphides,  and  some  alkali 
sulphates.  On  boiling  with  acids  it  yields  acid  albuminate,  peptone  sub- 
stances, chondroitin-sulphuric  acid,  and  on  account  of  the  further  decompo- 
sition of  this  lust  body  sulphuric  acid  and  a  reducing  substance  are  formed. 

Chondromucoid  is  a  white,  amorphous,  acid-reacting  powder  which  is 
insoluble  in  water,  but  dissolves  easily  on  the  addition  of  a  little  alkali. 
This  solution   is  precipitated  by  acetic  acid  in  great  excess  and  by  small 

'Zeitsclir.  f.  physiol.  Chem.,  Bd.  18,  S.  250. 

'Mucin  in  Myxoedema.  Further  Analyses.  Kings  College.  Collected  Papers  No.  1, 
1893. 

Olorochowctz,  Verbandl.  d.  naturli.  med.  Vereins  zu  Heidelberg,  Bd.  1,  Heft  3; 
MOrucr,  Skaud.  Arch.  f.  pliysiol.,  Bd.  1. 


HIS  TISSUES   OF  THE  CONNECTIVE  SUBSTANCE. 

quantities  of  mineral  acids.  The  precipitation  may  be  retarded  by  neutral 
salts  or  by  chrondroitin-sulphuric  acid.  The  solution  containing  NaCl  and 
acidified  with  HCl  is  not  precipitated  by  potassium  ferrocyanide.  Precipi- 
tants  for  chondromucoid  are  alum,  ferric  chloride,  sugar  of  lead  or  basic  lead 
acetate.  Chondromucoid  is  not  precipitated  by  tannic  acid,  and  it  may  by 
its  presence  prevent  the  precipitation  of  gelatin  by  this  acid.  It  gives  the 
usual  color  reactions  for  proteids,  namely,  with  nitric  acid,  with  copper  sul- 
phate and  alkali,  with  Million's  and  Adamkiewicz's  reagents. 

Chondroitin-sulphuric  Acid,  chondkoitic  acid.  This  acid,  which  was 
first  prepared  pure  from  cartilage  by  C.  Th.  Mornek,  and  identified  by 
him  as  an  ethereal  sulphuric  acid,  occurs  according  to  Morxer  in  all 
varieties  of  cartilage  and  also  in  the  tunica  intima  of  the  aorta  and  as 
traces  in  the  bone  substance.  According  to  Krawkow,  who  found  it  in  the 
cervical  ligament  of  the  ox,  it  combines  with  proteid  forming  amyloid 
(see  page  49),  which  explains  the  occurrence  of  this  body  in  amyloid-de- 
generated livers  as  observed  by  Oddi/  According  to  Schmiedeberg^  the 
acid  has  the  formula  C^  Ji^^NSO,,.  In  regard  to  the  chemical  constitution 
of  this  acid  the  investigations  of  Schmiedeberg  have  led  to  the  following  : 

As  first  products  this  acid  yields  on  cleavage  sulphuric  acid  and  a  nitrog- 
enous substance,  chondroitin,  according  to  the  following  equation: 

C..H„NSO„  +  H,0  =  H^SO,  +  C„H„NO,,. 

Chondroitin,  which  is  similar  to  gum  arable  and  which  is  a  monobasic  acid, 
yields  acetic  acid  and  a  new  nitrogenous  substance,  chondrosin,  as  cleavage 
products,  on  decomposition  with  dilute  mineral  acids : 

C,,H„NO,,  +  3H,0  =  3C,H,0,  +  C„H,.NO„. 

Chondrosin,  which  is  also  a  gummy  substance  soluble  in  water,  is  a  mono- 
basic acid  and  reduces  copper  oxide  in  alkaline  solution  even  more  strongly 
than  dextrose.  It  is  dextrogyrate  and  represents  the  reducing  substance 
obtained  by  previous  investigators  in  an  impure  form  on  boiling  cartilage 
with  an  acid.  The  products  obtained  on  decomposing  chondrosin  with 
barium  hydrate  tend  to  show  that  chondrosin  contains  the  atomic  groups  of 
glycuronic  acid  and  glucosamine. 

Chondroitin-sulphuric  acid  appears  as  a  white  amorphous  powder,  which 
dissolves  very  easily  in  water,  forming  an  acid  solution  and,  when  sufficiently 
concentrated,  a  sticky  liquid  similar  to  a  solution  of  gum  arable.  Nearly  all 
of  its  salts  are  soluble  in  water.  The  neutralized  solution  is  precipitated  by 
tin  chloride,  basic  lead  acetate,  neutral  ferric  chloride,  and  by  alcohol  in  the 

'  C.  Miirner,  1.  c,  and  Zeitschr.  f.  pbysiol.  Chem.,  Bdd.  20  and  23  ;  K.  Morner.  Skand. 
Arch.  f.  Pliysiol.,  Bd.  6  ;  Krawkow,  Arch  f.  exp.  Path.  u.  Pharm.,  Bd.  40  ;  Oddi,  ibid.^ 
Bd.  33. 

»  Arch.  f.  exp.  Path   u.  Pharm.,  Bd.  28. 


CnONDROMUCOIT)   AND  CUONDROITIN-SULPIIUIilC  ACID.        'M^ 

preseuce  of  a  little  neiUral  salt.  The  solution,  on  tlie  other  hand,  is  not 
precipitated  by  acetic  acid,  tannic  acid,  potassium  ferrocyanide  and  acid, 
sugar  of  lead,  mercuric  chloride,  or  silver  nitrate.  Acidified  solutions  of 
alkali  chondroitin-sulpliates  cause  a  precipitation  when  added  to  solutions  of 
gelatin  or  proteid. 

Chondromucoid  and  chondroitin-sulphuric  acid  may  be  j^reparod  accord- 
ing to  MoKXKK  by  extracting  finely  cut  cartilage  with  water,  whicli  dissolves 
the  ])roformed  chondroitin-sulphuric  acid  besides  some  chondromucoid.  In 
this  watery  extract  the  chondroitiu-.sulpliuric  acid  prevents  the  i)recipitation 
of  the  chondromucoid  by  means  of  an  acid.  If  2-4  p.  m.  IICl  is  added  to 
this  watery  extract  and  warmed  on  the  water-bath,  the  chondromucoid  grad- 
ually separates,  wliile  the  chondroitin-sulphuric  acid  and  the  rest  of  the 
chondromucoid  remain  in  the  filtrate.  If  the  cartilage,  which  has  been 
lixiviated,  at  the  temperature  of  the  body,  with  water,  is  extracted  with 
hydrocliloric  acid  of  2-3  p.  m.  until  the  collagen  is  converted  into  gelatin 
and  dissolved,  the  remaining  chondromucoid  may  be  removed  from  the  in- 
soluble residue  by  dilute  alkali  and  precipitated  from  the  alkaline  extract 
by  an  acid.  It  may  be  puritied  by  repeated  solution  in  water  with  the  aid  of 
a  little  alkali,  precipitating  by  an  acid  and  then  treating  with  alcohol  and 
ether. 

The  pre-existing  chondroitin-sulphuric  acid,  or  that  formed  by  the  de- 
composition of  chondromucoid,  is  obtained  by  lixiviating  the  cartilage  with 
a  b^  caustic-alkali  solution.  The  alkali  albuminate  formed  by  the  decom- 
})Osition  of  the  chondromucoid  can  be  removed  from  the  solution  by  neutral- 
ization, then  the  peptone  precipitated  by  tannic  acid,  the  excess  of  tiiis  acid 
removed  with  sugar  of  lead,  and  the  lead  separated  from  the  filtrate  by  II  S. 
If  further  purification  is  necessary,  the  acid  is  precipitated  with  alcohol,  the 
precipitate  dissolved  in  water,  this  solution  dialyzed  and  precipitated  again 
with  alcohol, — this  solution  in  water  and  precipitating  with  alcohol  being 
repeated  a  few  times, — and  lastly  the  acid  is  treated  with  alcohol  and  ether. 

ScHMiEDEBERG  prepared  the  acid  from  the  septum  narium  of  the  ])ig 
according  to  the  following  method:  The  finely  divided  cartilage  is  first  ex- 
posed to  artificial  j)epsin  digestion  and  then  carefully  washed  with  water  and 
the  insoluble  residue  treated  with  2-3^'*  hydrochloric  acid.  This  cloudy 
liquid  containing  hydrochloric  acid  is  precipitated  with  alcohol  (about  4  vol!) 
and  the  clear  filtrate  treated  Avith  absolute  alcohol  and  some  ether.  The 
precipitate,  consisting  chiefly  of  a  combination  or  a  mixture  of  chondroitin- 
suljihuric  acid  and  gelatin  peptone  (pepto-chondrin),  is  first  washed  Avith 
alcohol  and  then  with  water.  It  is  then  dissolved  in  alkaline  water  and  the 
basic  alkali  combination  precipitated  from  this  solution  by  the  addition  of 
alcohol,  wliorcby  the  gelatin-peptone  alkali  remains  in  solution.  'J'he  ]>re- 
cipitate  is  puritied  by  repeated  solution  in  alkaline  water  aiul  precipitated  by 
alcoliol.  To  obtain  chondroitin-sulphuric  acid  entirely  free  from  chondroitin 
it  is  more  advantageous  to  prepare  the  potassium-copjier  combination  of  the 
acid  from  the  alkaline  solution  by  the  alternate  addition  of  copper  acetate 
and  caustic  potash  and  precipitating  with  alcohol.  The  reader  is  referred  to 
the  original  article  for  more  details. 

The  collngcn  of  the  cartilage  gives,  according  to  Morner,  a  gelatin  which 
contains  only  16.4,'^  N  and  which  can  hardly  be  considered  identical  with 
ordinary  gelatin. 


320  TISSUES   OF  THE  CONNECTIVE  SUBSTANCE. 

In  the  above-mentioned  cartilages  of  full-grown  animals  the  chondroi tin- 
sulphuric  acid  and  chondromucoid,  perhaps  also  the  collagen,  are  found  sur- 
rounding the  cells  as  round  balls  or  lumps.  These  balls  (Morner's  cUondrin- 
balls),  which  give  a  blue  color  with  methyl-violet,  lie  in  the  meshes  of  a 
trabecular  structure,  which  is  colored  when  brought  in  contact  with  tro- 
pieolin. 

The  albuminoid  is  a  nitrogenized  body  which  contains  loosely  combined 
sulphur.  It  is  soluble  with  difficulty  in  acids  and  alkalies,  and  resembles 
keratin  in  many  respects,  but  differs  from  it  by  being  soluble  in  gastric  juice. 
In  other  respects  it  is  more  similar  to  eiastin,  but  differs  from  this  substance 
by  containing  sulphur.  This  albuminoid  gives  the  color  reactions  of  the 
albuminous  bodies. 

The  preparation  of  cartilage-gelatin  and  albuminoid  may  be  performed 
according  to  the  following  method  of  Morner:  First  remove  the  chon- 
dromucoid  and  chondroitin-sulphuric  acid  by  extraction  with  dilute  caustic 
potash  (0.2-0.5^),  remove  the  alkali  from  the  remaining  cartilage  by  water, 
and  then  boil  with  water  in  a  Papin's  digester.  The  collagen  passes  into 
solution  as  gelatin,  while  the  albuminoid  remains  undissolved  (contaminated 
by  the  cartilage -cells).  The  gelatin  may  be  purified  by  precipitating  with 
sodium  sulphate,  which  must  be  added  to  saturation  in  the  faintly  acidified 
solu^n,  redissolving  the  precipitate  in  water,  dialyzing  well,  and  precipi- 
tating with  alcohol. 

According  to  Morner,  no  albuminoid  is  found  in  young  cartilage,  but 
only  the  three  first-mentioned  constituents.  Nevertheless  the  young  carti- 
lage contains  about  the  same  amounts  of  nitrogen  and  mineral  substances  as 
the  old.  The  cartilage  of  the  ray  {Raja  latin  LiN^.),  which  has  been  investi- 
gated by  LoNXBERG,'  contains  no  albuminoid  and  only  a  little  chondromu- 
coid,  but  a  large  proportion  of  chondroitin-sulphuric  acid  and  collagen. 

Hoppe-Seyler  found  in  fresh  human  rib-cartilage  676.7  p.  m.  water, 
301.3  p.  m.  organic  and  22  p.  m.  inorganic  substance,  and  in  the  cartilage 
of  the  knee-joint  735.9  p.  m.  water,  248.7  p.  m,  organic,  and  15.4  p.  m. 
inorganic  substance.  Pickardt  "  found  402-574  p.  m.  water  and  72.86  p.  m. 
ash  (no  iron)  in  the  laryngeal  cartilage  of  oxen.  The  ash  of  cartilage  con- 
tains considerable  amounts  (even  800  p.  m.)  of  alkali  sulphate,  which 
probably  does  not  exist  originally  as  such,  but  is  produced  in  great  part  by 
the  incineration  of  the  chondroitin-sulphuric  acid  and  the  chondromucoid. 
The  analyses  of  the  ash  of  cartilage  therefore  cannot  give  a  correct  idea  of 
the  quantity  of  mineral  bodies  existing  in  this  substance. 

The  Cornea.  Tho  corneal  tissue,  which  is  considered  by  many  investi- 
gators to  be  related  to  cartilage  in   a   chemical   sense,  contains  traces  of 

>  Maly's  Jahresber,  Bd.  19,  8.  335. 

^  Hoppe-Seylcr,  cited  from  Kiiline's  Lehrbucb,  d.  physiol.  Chem.,  S.  387;  Pickardt, 
Centralbl.  f.  Physiol.,  Bd.  6,  B.  735. 


BONE.  321 

proteid  and  a  collagen  as  cliief  constituent,  which  C.  Tu.  Muknek  '  claims 
contains  16.95^  N.  According  to  him  it  also  contains  a  mucoid  which  lias 
the  composition  C  50. IG,  U  G.97,  N  12.79,  and  S  2.07^.  On  boiling  with 
dilute  mineral  acid  this  mucoid  yields  a  reducing  substance.  The  globulins 
found  by  other  investigators  in  the  cornea  are  not  derived  from  the  matrix, 
according  to  Morxkk,  but  from  the  layer  of  epithelium.  According  to 
MoRNER,  Descemet's  membrane  consists  of  membranin  (page  48),  which 
contains  14.77^  N  and  0.90^  S. 

In  the  cornea  of  oxen  Ills'"  found  758.3  p.  m.  water,  203.8  p.  m.  gela- 
tin-forming substance,  28.4  p.  m.  otber  organic  substance,  besides  8.1  p.  m. 
soluble  and  1.1  p.  m.  insoluble  salts. 

III.    Bone. 

The  bony  structure  proper,  when  free  from  other  formations  occurring 
in  bones,  such  as  marrow,  nerves,  and  blood-vessels,  consists  of  cells  and  a 
matrix. 

The  cells  have  not  been  closely  studied  in  regard  to  their  chemical  con- 
stitution. On  boiling  with  water  they  yield  no  gelatin.  They  contain  no 
keratin,  which  is  not  usually  present  in  the  bony  structure  (Herbert 
Smith'),  but  they  may  contain  a  substance  which  is  similar  to  elastin. 

The  matrix  of  the  bony  structure  contains  two  chief  constituents, 
namely,  an  organic  substance,  ossein,  and  the  so-called  hone-earths,  lime- 
salts,  enclosed  in  or  combined  with  it.  If  bones  are  treated  with  dilute 
hydrochloric  acid  at  the  ordinary  temperature,  the  lime-salts  are  dissolved 
and  the  ossein  remains  as  an  elastic  mass,  preserving  the  shape  of  the  bone. 
This  ossein  is  generally  considered  identical  with  the  collagen  of  the  con- 
nective tissue. 

The  inorganic  constituents  of  tlie  bony  structure,  the  so-called  bo7ie- 
earths,  which  remain  after  the  complete  calcination  of  the  organic  sub- 
stance as  a  white,  brittle  mass,  consist  chiefly  of  calcium  and  phosphoric 
acid,  but  also  contain  carbon  dioxide  and,  in  smaller  amounts,  magnesium, 
chlorine,  and  fluorine.  Alkali  sulphate  and  iron,  which  have  been  found 
in  bone-ash,  do  not  seem  to  belong  exactly  to  the  bony  substance,  but  to 
the  nutritive  fluids  or  to  tlie  other  constituents  of  bones.  Tlie  traces  of 
sulphate  occurring  in  the  bone-ash  is  derived,  according  to  Morxer,*  from 
the  chondroitin-sulphuric  acid.  According  to  Gabriel*  potassium  and 
sodium  are  essential  constituents  of  bone-earth. 

"  Zeltschr.  f.  physiol.  Chem.,  Bd.  18. 

'  Cited  from  Ganigee,  Physiol.  Chem.,  1880,  p.  451. 

i  Zeitschr.  f.  Biologie,  Bd.  19. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  23. 

*  Ibid.,  18,  which  iilso  coutains  the  pertinent  literature. 


Ox. 

Tortoise. 

Guinea-pi; 

860.9 

859.8 

873.8 

10.2 

13.6 

10.5 

73.6 

63.2 

70.3 

62.0 

52.7 

2.0 

1.3 

3.0 

2.0 

0-22  TliiSUES   OF  THE  COXXECTIVE  SUBSTAXCE. 

The  opiuious  of  investigators  differ  somewhat  as  to  the  manner  ia 
-which  the  mineral  bodies  of  the  hour  structure  are  combined  with  each 
other.  Chlorine  and  fluorine  are  present  in  the  same  form  as  in  apatite 
(CaFl,,3Ca3p,Og).  If  we  eliminate  the  magnesium.,  the  chlorine,  and  the 
fluorine,  the  last,  according  to  Gabriel,  occurring  only  as  traces,  the 
remaining  mineral  bodies  form  the  combination  3(Ca3P,OJCaCO,.  Accord- 
ins  to  Gabeizl,  the  simplest  expression  for  the  composition  of  the  ash  of 
bones  and  teeth  is  (Ca,(POJ,  +  Ca.HP.O,^  —  Aq),  in  which  2-3^  of  the 
lime  is  replaced  by  magnesia,  potash,  and  soda,  and  Jr-G*^  of  the  phosphoric 
acid  by  carbon  dioxide,  chlorine,  and  fltiorine. 

Analyses  of  bone-earths  have  shown  that  the  mineral  constituents  exist  in 
rather  constant  proportions,  which  is  nearly  the  same  in  different  animals. 
As  example  of  the  composition  of  bone-earth  we  give  here  the  analyses  of 
Zaleskt."-     The  figures  represent  parts  per  thousand. 

Man. 

Calcium  phosphate.  CasP^O, 838.9 

Magnesium  phosphate,  MgsPiOg  10.4 

Calcium  combined  with  CO2,  Fi.  andjCl 76.5 

CO2 57.3 

Chlorine 1.8 

Fluorine 2.3 

Some  of  the  CO2  is  always  lost  on  calcining,  so  that  the  bone-ash  does  not  contain 
the  entire  CO3  of  the  bony  substance. 

Ad.  Caexot  "  found  the  following  composition  for  the  bone-ash  of  man,. 

ox,  and  elephant : 

Man.  Ox.         Elephant. 

Femur       Femur         Femur.       Femur, 
(body).       (head). 

Calcium  phosphate 874.5  878.7  857.2  900.3 

Maenesium  phosphate 15.7  17.5  15.3  19.6 

Calcium  fluoride     3.5  3.7  4.5  4.7 

Calcium  chloride  2.3  3.0  3.0  2.0 

Calcium  carbonate 101.8  92.3  119.6  72.7 

Iron  oxide 10  1.3  1.3  1.5 

The  quantity  of  organic  substance  in  the  bones,  calculated  from  the  loss 

of  ■weight  in  burning,  varies  somewhat  between  300  and  520  p.  m.     This 

variation  may  in  part  be  explained  by  the  difficulty  in  obtaining  the  bony 

substance  entirely  free  from  water,  and  partly  by  the  very  variable  amount 

of   blood-vessels,  nerves,   marrow,  and  the  like,  in  different  bones.     The 

unequal  amounts  of  organic  substance  found  in  the  compact  and  in  the 

spongy  parts  of  the  same  bone,  as  well  as  in  bones  at  different  periods 

of  development   in  the  same  animal,  depend  probably  upon  the  varying 

quantities  of  these  above-mentioned  formations.     Dentin,  which  is  compare  ■ 

tively  pure  bony  structure,  contains  only  260-280  p.  m.  organic  substance, 

and  Hoppe-Seyler  '  therefore  thinks  it  probable  that  entirely  pure  bony 

'  Hoppe-Seyler,  Med.  ehem.  Untersuch.,  S.  19. 
'  Comp.  rend.,  Tome  114. 
'  Physiol.  Chem..  S.  102-104. 


COMPOSITJVN    Oh'  BONE.  323 

substance  has  a  constant  composition  and  contains  only  about  250  j).  ni. 
organic  substance.  The  question  whether  these  substances  are  chemically 
combined  with  the  bone-earths  or  only  intimately  mixed  has  not  been 
decided. 

Tiie  nutritive  lluids  whicli  cirfulnti;  Miroiigli  the  liones  have  not  been  isolated,  and 
we  only  Icnow  lliat  tliey  contain  some  protrid  and  some  NaCl  and  alkali  sulpliate.  The 
yellow  marrow  contains  cliicfly  Cut,  which  consists  of  olein,  painiitiu,  and  stearin. 
Proleid  has  been  found  especially  in  th(!  so-called  red  marrow  of  the  spongy  bones. 
Accordini,'  to  FouitEST  the  proteid  consisis  of  a  globulin  coagulating  at  Al-T)(f  C.,  and 
a  nucleoalbumin  with  1.6;?  phosphorus  (Halmhurton ').  besides  traces  of  albumin. 
Besides  this  the  marrow  contains  so-called  extractive  Imdies,  such  as  lactic  acid, 
hypo.xanthin,  and  cholesleria,  but  mostly  bodies  of  au  unknown  character. 

The  diverse  quantitative  composition  of  the  various  bones  of  the  skeleton 
depends  probably  on  the  varying  quantities  of  other  formations,  such  as 
marrow,  blood-vessels,  etc.,  they  contain.  The  same  reason  explains,  to 
all  appearances,  the  larger  quantity  of  organic  substance  in  the  spongy  jiarts 
of  the  bones  as  compared  with  the  more  compact  parts.  Schrodt''  has  made 
comparative  analyses  of  different  parts  of  the  skeleton  of  the  same  animal 
(dog),  and  has  found  an  essential  difFerence.  The  quantity  of  water  in  the 
fresh  bones  varies  between  138  and  443  p.m.  The  bones  of  the  extremities 
and  the  skull  contain  138-222,  the  vertebrae  168-443,  and  the  ribs  324-356 
p.  m.  water.  The  quantity  of  fat  varies  between  13  and  269  p.  m.  The 
largest  amount  of  fat,  256-269  p.  m.,  is  found  in  the  long  tubular  bones^ 
while  only  13-175  p.  m.  fat  is  found  in  tlic  small  short  bones.  The  quan- 
tity of  organic  substance,  calculated  from  fresh  bones,  was  150-300  p.  m.„ 
and  the  quantity  of  mineral  substances  290-563  p.  m.  Contrary  to  the 
general  supposition  the  greatest  amount  of  bone-earths  was  not  found  in  the 
femur,  but  in  the  first  three  cervical  vertebra?.  Iti  birds  the  tubular  bones 
are  richer  in  mineral  substances  than  in  the  flat  bones  (During),  and  the 
greatest  quantity  of  mineral  bodies  has  been  found  in  the  humerus  (Hiller,. 
During  '). 

AV'e  do  not  possess  trustworthy  statements  in  regard  to  the  composition 
of  bones  at  different  ages.  According  to  the  analyses  by  E.  Voit  of  l)ones 
of  dogs  and  by  Brubacrer  of  bones  of  children,  we  learn  that  the  skeleton 
becomes  poorer  in  water  and  richer  in  ash  with  increase  in  age.  Graffen- 
BERGER*  has  found  in  rabbits  6i-7^  years  old  that  the  bones  contained  only 
140-170  p.  m.  water,  while  the  bones  of  the  full-grown  rabbit  2-4  years  old 
contained  200-240  p.  m.  The  bones  of  old  rabbits  contain  more  carbon 
dioxide  and  less  calcium  phosphate. 

'  Forrest,  Journ.  of  Physiol.,  Vol.  17  ;     Halliburton,    ihid..  Vol.  18. 

^Landwirthsch.  Versuchsstat.,  Bd.  19.     Cited  from  Maly's  Jahresber.,  Bd.  6. 

'Hiller,  cited  from  Maly's  Jahresber.,  Bd.  14;  Diirinjr,  Zeitschr.  f.  ph3•t^iol.  cbem. 
Bd.  23. 

'  Voit,  Zeitschr.  f.  Biologie,  Bd.  16;  Brubacher,  ibid.,  Bd.  37;  Graffenberger  in 
IVIalv's  Jahresber.,  Bd.  21. 


324  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

The  composition  of  bones  of  animals  of  different  species  is  but  little  known.  The 
bones  of  birds  contain,  as  a  rule,  somewhat  more  water  than  those  of  mammaliii,  aud 
the  bones  of  fishes  contain  the  largest  quantity  of  water.  The  bones  of  fishes  and  amphib- 
ians contain  a  greater  amount  of  organic  substance.  The  bones  of  pachyderms  and 
cetaceans  contain  a  large  proportion  of  calcium  carbonate  ;  those  of  granivorous  birds 
always  contain  silicic  acid.  The  bone-ash  of  amphibians  and  fishes  contains  sodium 
sulphate.  The  bones  of  fishes  seem  to  contain  more  soluble  salts  than  the  bones  of  other 
animals. 

A  great  many  experiments  have  been  made  to  determine  the  exchange  of 
material  in  the  bones — for  instance,  with  food  rich  in  lime  and  with  food 
deficient  in  lime — but  the  results  have  always  been  doubtful  or  contradic- 
tory. The  attemjDts,  also,  to  substitute  other  alkaline  earths  or  clay  for  the 
lime  of  the  bones  have  given  contradictory  results.'  On  the  administration 
of  madder  the  bones  of  tlie  animal  are  found  to  be  colored  red  after  a  few 
days  or  weeks  ;  but  these  experiments  have  not  led  to  any  jpositive  conclu- 
sion in  regard  to  the  growth  or  metabolism  in  the  bones. 

Under  pathological  conditions,  as  in  rachitis  and  softening  of  the  bones, 
an  ossein  has  been  found  which  does  not  give  any  typical  gelatin  on  boiling 
with  water.  Otherwise  pathological  conditions  seem  to  affect  chiefly  the 
quantitative  composition  of  the  bones,  and  especially  the  relationship  be- 
tween the  organic  and  the  inorganic  substance.  In  exostosis  and  osteosclerosis 
theyquantity  of  organic  substance  is  generally  increased.  In  rachitis  and 
osteomalacia  the  quantity  of  bone-earths  is  considerably  decreased.  At- 
tempts have  been  made  to  produce  rachitis  in  animals  by  the  use  of  food  de- 
ficient in  lime.  From  experiments  on  fully  developed  animals  contradictory 
results  have  been  obtained.  In  yoitng,  undeveloi^ed  animals  Eravix  Yoit^ 
produced,  by  lack  of  lime-salts,  a  change  similar  to  rachitis.  In  full-grown 
animals  the  bones  were  changed  after  a  long  time  because  of  the  lack  of 
lime-salts  in  the  food,  but  did  not  become  soft,  only  thinner  (osteojoorosis). 
The  experiments  of  removing  the  lime-salts  from  the  bones  by  the  addition 
of  lactic  acid  to  the  food  have  led  to  no  j^ositive  results  (HEiTZMANiSr,  Heiss? 
Baginsky).'  "Weiske,  on  the  contrary,  has  shown, by  administering  dilute 
sulphuric  acid  or  monosodium  phosphate  with  the  food  (presupposing  that 
the  food  gave  no  alkaline  ash)  to  sheep  and  rabbits,  that  the  quantity  of 
mineral  bodies  in  the  bones  might  be  diminished.  On  feeding  continuously 
for  a  long  time  with  a  food  which  yielded  an  acid  ash  (cereal  grains)  Weiske 
has  observed  a  diminution  in  the  mineral  substances  of  the  bones  in  full- 
grown  herbivora.''  A  few  investigators  are  of  the  opinion  that  in  rachitis,  as 
in  osteomalacosis,  a  solution  of  the  lime-salts  by  means  of  lactic  acid  takes 

'  See  H.  Weiske,  Zeitschr.  f.  Biologic,  Bd.  31. 

-  Zeitschr.  f.  Biologic,  Bd.  16. 

'Heitzmaun,  Maly's  Jahresber.,  Bd.  3,  S.  229  ;  Heiss,  Zeitchr.  f.  Biologie,  Bd.  12; 
Baginsky,  Virchow's  Arch,,  Bd.  87. 

"•See  Maly's  Jahresber.,  Bd.  22;  also  Weiske,  Zeitschr.  f.  physiol.  Chem.,  Bd.  20, 
and  Zeitschr.  f.  Biologie,  Bd.  31. 


TOOTn  STRUCTURE.  325 

place.     This  was  suggested  by  the  fact  that  0.  Weber  and  C.  .Schmidt 
found  hictic  acid  in  the  cyst-like,  altered  bony  substance  in  osteomalacia. 

Well-known  investigators  have  disputed  tlie  possibility  of  the  lime-salts 
being  washed  from  the  bones  in  osteomalacosisby  means  of  lactic  acid.  They 
have  given  special  prominence  to  the  fact  that  the  lime-salts  held  in  solution 
by  the  lactic  acj<l  must  be  deposited  on  neutralization  of  the  acid  by  the 
alkaline  blood.  This  objection  is  not  very  important,  as  the  alkaline  stream 
of  blood  has  the  property  to  a  high  degree  of  holding  earthy  phosphates  in 
solution,  which  can  be  easily  proved.  The  recent  investigations  of  Levy  * 
contradict  the  statement  as  to  the  solution  of  the  lime-salts  by  lactic  acid  in 
osteomalacia.  He  has  found  that  the  normal  relationship  GPO^  :  lOCa  is 
retained  in  all  parts  of  the  bones  in  osteomalacia,  which  would  not  be  the 
case,  if  the  bone-earths  were  dissolved  by  an  acid.  The  decrease  in  phos- 
phate occurs  in  the  same  quantitative  relationship  as  the  carbonate,  and 
according  to  Levy  in  osteomalacia  the  exhaustion  of  the  bone  takes  place 
by  a  decalcification  in  which  one  molecule  of  phosj^hate  carbonate  after  the 
other  is  removed. 

Id  rachitis  the  quantity  of  organic  matter  has  been  found  to  vary  between  064  and 
811  p.  m.  The  (quantity  of  inorganic  substance  was  189-3;36  p.  m.  These  figures  refer 
to  tlie  dried  substance.  According  to  Bhubachkr  racliitic  bones  are  richer  in  water 
than  the  bones  of  healthy  chihiren,  and  poorer  in  mineral  bodies,  especially  calcium 
phosphate.  In  opposition  to  rachitis,  osteomalacosis  is  often  cliaracterize<l  by  tlie  con- 
siderable amount  of  fat  in  tlie  bones.  230-290  p.  m.  ;  but  as  a  rule  llie  composition  varie.s 
so  much  that  the  analyses  are  of  little  value.  In  a  case  of  osteomalacosis  CiiAuuifi  '  found 
a  larger  quantity  of  magnesium  than  calcium  in  a  bone.  The  ash  contained  417  p.  m. 
phospboiic  acid,  222  p.  m.  lime,  269  p.  m.  magnesia,  and  86  p.  m.  carbon  dioxide. 

The  tooth-structure  is  nearly  related,  from  a  chemical  standpoint,  to  the 
bony  structure. 

Of  the  three  chief  constituents  of  the  teeth,  dentin,  enamel,  and  cement, 
the  last-mentioned,  the  cement,  is  to  be  considered  as  true  bony  structure, 
and  as  such  has  already  been  discussed  to  some  extent.  Dentin  has  the 
same  composition  as  the  bony  structure,  but  contains  somewhat  less  water. 
The  organic  substance  yields  gelatin  on  boiling;  but  the  dental  tubes  are 
not  dissolved,  therefore  they  cannot  consist  of  collagen.'  In  dentin  2^0-2^0 
p.  m.  organic  substance  has  been  found.  Enamel  is  an  epithelium  forma- 
tion containing  a  large  proportion  of  lime-salts.  The  organic  substance  of 
the  enamel  does  not  yield  any  gelatin.  Completely  developed  enamel  con- 
tains the  least  water,  the  greatest  quantity  of  mineral  substances,  and  is  the 
hardest  of  all  the  tissues  of  the  body.  In  full-grown  animals  it  contains 
hardly  any  water,  and  the  quantity  of  organic  substance  amounts  to  oiily 
20-40  p.  m.     According  to  Tomes*  the  enamel  contains  no  measurable 

Cited  from  v.  Gorup-Besanez,  Lehrb.  d.  physiol.  Chem.,  4.  Aufl. 
'Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 

3  Chabrie,  "  Les  phenomtines  chim.  de  rossilication,"  Paris,  1895,  p.  65. 
■•  Journ.  of  Physiol.,  Vol.  19. 


326  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

amounts  of  organic  matter,  and  what  used  to  be  called  organic  matter  (loss 
by  weight  in  incineration)  he  considers  only  water.  The  relative  amounts 
of  calcium  and  phosphoric  acid  are,  according  to  the  analyses  of  Hoppe- 
Seyler,  about  the  same  as  in  bone-earths.  The  quantity  of  chlorine  ac- 
cording to  Hope-Seyler'  is  remarkably  high,  0.3-0.5,^. 

Carnot,'  who  has  investigated  the  dentiu  from  elephants,  has  found  4.3  p.  m.  calcium 
fluoride  in  the  ash.  In  ivory  he  found  only  2.0  p.  m.  Dentin  from  elephants  is  rich 
in  magnesium  phosphate,  which  is  more  murked  in  ivory. 

According  to  Gabriel  the  amount  of  fluorine  is  very  small  and  amounts 
to  1  p.  m.  in  ox-teeth.  It  is  no  greater  in  the  teeth  and  enamel  than  in 
the  bones.  According  to  Gabriel  the  phosphates  are  strikingly  small  in 
the  enamel,  and  in  the  teeth  considerable  lime  is  replaced  by  magnesia. 

IV.   The  Fatty  Tissue. 

The  membranes  of  the  fat-cells  withstand  the  action  of  alcohol  and 
ether.  They  are  not  dissolved  by  acetic  acid  nor  by  dilute  mineral  acids, 
but  are  dissolved  by  artificial  gastric  juice.  They  may  possibly  consist  of  a  sub- 
stance closely  related  to  elastin.  The  fat-cells  contain,  besides  fat,  a 
yellow  pigment  which  in  emaciation  does  not  disappear  so  rapidly  as  the 
fat; /and  this  is  the  reason  that  the  subcutaneous  cellular  tissue  of  an 
emaciated  corpse  has  a  dark  orange-red  color.  The  cells  deficient  in  or 
nearly  free  from  fat,  which  remain  after  the  complete  disappearance  of  the 
latter,  seem  to  have  an  albuminous  protoplasm  rich  in  water. 

The  less  water  the  fatty  tissue  contains  the  richer  it  is  in  fat.  Schulze 
and  Reinecke  '  found  in  1000  parts : 

Water.  Membrane.  Fat. 

Fatty  tissue  of  oxen i  99.7  16.6  883.7 

"       "    sheep 104.8  16.4  878.8 

"       '■    pigs 64.4  13.6  932.0 

The  fat  contained  in  the  fat-cells  consists  chiefly  of  triglycerides  of 
stearic,  palmitic,  and  oleic  acids.  Besides  these,  especially  in  the  less  solid 
kinds  of  fats,  there  are  glycerides  of  other  fatty  acids.  (See  Chapter  IV.) 
In  all  animal  fats  there  are  besides  these,  as  Hofmanx  *  has  shown,  also 
free,  non-volatile  fatty  acids,  although  in  very  small  amounts. 

Human  fat  in  adults  is  rich  in  olein  (about  70^).  In  new-born  infants  it 
is,  according  to  Knopfelmacher,'  poorer  in  oleic  acid  than  in  adults,  as  it 
amounts  to  only  about  43.3^  of  the  total  fatty  acids.  The  oleic  acid  then 
increases  until  the  end  of  the  first  year,  when  it  is  the  same  as  in  adults 
(65^).     The  fat  of  the  domestic  animals  has,  according  to  Amthor  and 

'  Phy.siol.  Chem.,  p.  180. 

'  Compt.  rend..  Tome  114. 

3  Annal.  d.  Chem.  u.  Pharra.,  Bd.  142. 

*  Ludwig-Fcslschrift,  1874.     Leipzig. 

''See  foot-note  1,  page  93. 


FORMATION  OF  FAT.  327 

ZiNK,'  a  less  oily  consistency  and  a  lower  iodine  and  acetyl  equivalent  than 
the  corresponding  fat  of  wild  animals.  The  fat  of  cold-blooded  animals  is 
remarkably  rich  in  olein. 

The  properties  of  fats  in  general,  and  the  three  most  important  varieties 
of  fat,  have  already  been  treated  of  in  a  previous  chapter,  hence  the  forma- 
tion of  the  adipose  tissue  is  of  chief  interest  at  this  time. 

The  formation  of  fat  in  the  organism  may  occur  in  various  ways.  The 
fat  of  the  animal  body  may  consist  partly  of  absorbed  fat  of  the  food  de- 
posited in  the  tissues,  and  partly  of  fat  formed  in  the  organism  from  other 
bodies,  such  as  proteids  or  carbohydrates. 

That  the  fat  of  the  food  which  is  absorbed  in  the  intestinal  canal  may  be 
retained  by  the  tissues  has  been  shown  in  several  ways.  Hauzie.iewski, 
Lebedeff,  and  Munk'  have  fed  dogs  with  various  fats,  such  as  linseed-oil, 
mutton-tallow,  and  rape-sccd-oil,  and  have  afterwards  found  tlie  adminis- 
tered fat  in  the  tissues.  IIofmanx  starved  dogs  until  they  appeared  to  iiave 
lost  their  fat,  and  then  fed  them  upon  large  quantities  of  fat  and  only  little 
proteids.  When  the  animals  were  killed  he  found  so  large  a  quantity  of  fat 
that  it  could  not  have  been  formed  from  the  administered  proteids  alone, 
but  the  greatest  part  must  have  been  derived  from  the  fat  of  the  food. 
Pettenkofer  and  Voit  '  arrived  at  similar  results  in  regard  to  the  behavior 
of  the  absorbed  fats  in  the  organism,  though  their  experiments  were  of 
another  kind,  Munk  *  has  found  that  on  feeding  with  free  fatty  acids  these 
are  deposited  in  the  tissues,  not,  however,  as  such  ;  but  they  are  transformed 
by  synthesis  with  glycerin  into  neutral  fats  on  their  passage  from  the  intes- 
tine to  the  thoracic  duct.  Coronedi  and  Marchetti  and  especially  Win- 
TERNITZ "  have  recently  shown  that  the  iodized  fat  is  taken  up  in  the  in- 
testinal tract  and  deposited  in  the  various  organs: 

Proteids  and  carbohydrates  are  considered  as  the  mother-substance  of  the 
fats  formed  in  the  organism. 

The  formation  of  the  so-called  corpse-iuax,  adipocere,  which  consists  of  a 
mixture  of  fatty  acids,  ammonia,  and  lime-soaps,  from  parts  of  the  corpse  rich 
in  proteids,  is  sometimes  given  as  a  proof  of  i\\Q  formation  of  fats  from  pro- 
teids. The  accuracy  of  this  view  has,  however,  been  disputed,  and  many 
other  explanations  of  the  formation  of  this  substance  have  been  offered. 
According  to  the  recent  experiments  of  Kratter  and  K.  B.  Leiimaxx  it 
;seems  as  if  it  were  possible  by  experimental  means  to  convert  animal  tissue  rich 
in  proteids  (muscles)  into  adipocere  by  the  continuous  action  of  water.     Irre- 

'  Zeitschr.  f.  analyt.  Chem.,  Bd.  36. 

»  Riidiejewski,  Vircbow's  Arch.,  Bd.  43;  Munk,   ibid.,  Bd.   95;  Lobodeff,  Pfliiger's 
Arch..Bd.  31. 

s  Hoffmann,  Zeitschr.  f.  Biologic,  Bd.  8;  Pettenkofer  and  Voit,  tbixf.,  Bd.  9. 

*  Virchow's  Arch.  Bd.  80. 

*  Coronedi  and  Marchetti,  cited  by  Winternitz,  Zeitschr.  f.  physiol.  Chem.,  Bd.  24. 


328  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

spective  of  this,  Salkowski  '  lias  shown  recently  that  in  the  formation  of  adi- 
pocere  the  fat  itself  takes  part  in  that  the  olein  decomposes  with  the  forma- 
tion of  solid  fatty  acids;  still  it  must  be  considered  that  lower  organisms 
undoubtedly  take  part  in  its  formation.  The  production  of  adipocere  as  a 
proof  of  the  formation  of  fat  from  proteids  is  disputed  by  many  investigators 
for  this  and  other  reasons. 

Fatty  degeneration  is  another  proof  of  the  formation  of  fat  from  pro- 
teids. From  the  investigations  of  Bauer  on  dogs  and  Leo  on  frogs  we  must 
admit  that  at  least  in  acute  poisoning  by  phosphorus  a  fatty  degeneration 
with  the  formation  of  fat  from  proteids  takes  place.  Pfluger  "  has  raised 
such  strong  arguments  against  the  older  researches  as  well  as  the  more 
recent  of  Polimanti,  who  claims  to  have  shown  the  formation  of  fat  from 
proteids  in  phosphorus  poisoning,  that  we  cannot  consider  the  formation  of 
fat  as  conclusively  proved. 

Another  more  direct  proof  for  the  formation  of  fat  from  proteids  has 
been  given  by  Hofmann."  He  experimented  with  fly-maggots.  A  number 
of  these  were  killed  and  the  quantity  of  fat  determined.  The  remainder 
were  allowed  to  develop  in  blood  whose  proportion  of  fat  had  been  previously 
determined,  and  after  a  certain  time  they  were  killed  and  analyzed.  He 
found /in  them  from  7  to  11  times  as  much  fat  as  in  the  maggots  first 
analy/ed  and  the  blood  together  contained.  I^fluger"  has  made  the  objec- 
tion that  a  considerable  number  of  lower  fungi  develop  in  the  blood  under 
these  conditions,  and  these  serve  as  food  for  the  maggots  and  in  whose  cell- 
body  fats  and  carbohydrates  are  formed  from  the  different  constituents  of 
the  blood  and  their  decomposition  products. 

As  a  more  direct  proof  of  fat-formation  from  proteids  the  investigations 
of  Pettenkofer  andVoiT"  are  often  quoted.  These  investigators  fed  dogs 
with  large  quantities  of  meat  containing  the  least  possible  proportion  of  fat, 
and  found  all  of  the  nitrogen  in  the  excreta,  but  only  a  part  of  the  carbon. 
As  an  explanation  of  these  conditions  it  has  been  assumed  that  the  proteid 
of  the  organism  splits  into  a  nitrogenized  and  a  non-nitrogenized  part,  the 
former  changing  into  the  nitrogenized  final  product,  urea,  the  other,  on  the 
contrary,  being  retained  in  the  organism  "as  fat  (Pettenkofer  and  Voit). 

Pfluger'  has  arrived  at  the  following  conclusion  by  an  exhaustive  criti. 
cism  of  Pettekkofer  and  Yoit's  experiments  and  a  careful  recalculation 
of  their  balance-sheet,  namely,  that  these  very  meritorious  investigations, 

'Kratter,  Zeitschr.  f.  Biologie,  Bd.  16;  Lehmann,  Sitzungsber.  d.  WUrzburg.  pbys.- 
med.  Gesellsch.,  1888.     Salkowski,  Virchow-Festschrift,  1891. 

'  Bauer,  Zeitschr.  f.  Biologie,  Bd.  7;  Leo,  Zeitschr.  f.  physiol.  Chem.,  Bd.  9;  Polimanti,. 
Pfliiger's  Arch.,  Bd.  70  ;  Pfluger,  Pflilger's  Arch.,  Bdd.  51  and  71. 

^Zeithschr.  f.  Biologie,  Bd.  8. 

*  Liebig'.9  Anal.,  Snppl.  2,  and  Zeitschr.  f.  Biologie,  Bdd.  5  and  7. 

•Pflilger's  Arch.,  Bd.  51. 


FORMATION  OF  FAT.  329 

which  were  continued  for  a  series  of  years,  were  subject  to  such  great  defects 
that  they  are  not  conclusive  as  to  the  formation  of  fat  from  proteids.  lie 
especially  emphasizes  the  fact  that  these  investigators  started  from  a  wrong 
assumption  as  to  the  elementary  composition  of  tlie  meat,  and  tliut  tlie 
quantity  of  nitrogen  assumed  by  them  was  too  low  and  the  quantity  of 
carbon  too  high.  The  relationship  of  nitrogen  to  carbon  in  meat  poor  in  fat 
was  assumed  by  VoiT  to  bo  as  1  :  3.G8,  while  according  to  Pfluger  it  is 
1  :  3.22  for  fat-free  meat  after  deducting  the  glycogen,  and  according  to 
EuBNER  1  :  3.28  without  deducting  the  glycogen.  On  recalculating  the 
experiments  using  these  coefficients,  Pfluger  has  arrived  at  the  conclusion 
that  the  assumption  as  to  the  formation  of  fat  from  proteids  finds  no  support 
in  these  experiments. 

In  opposition  to  these  objections  E.  Voit  and  M.  Cremer  have  made 
new  feeding  experiments  to  show  the  formation  of  fat  from  proteids,  but  the 
proof  of  these  recent  investigations  has  been  denied  by  Pfluger.'  On 
feeding  a  dog  on  meat  poor  in  fat  (containing  a  known  quantity  of  ether 
extractives,  glycogen,  nitrogen,  water  and  ash),  Kumagawa'  could  not  prove 
the  formation  of  fat  from  proteids.  According  to  him  the  animal  body 
under  normal  conditions  has  not  the  power  of  forming  fat  from  proteid. 

Several  French  investigators,  especially  Chauveau,  Gautier  and  Kauf- 
MANN,'  consider  the  formation  of  fat  from  proteids  as  positively  proved. 
Kaufmann  has  recently  substantiated  tliis  view  by  a  metliod  wiiich  will 
be  spoken  of  in  detail  in  Chapter  XVIII,  in  which  he  studied  the  nitro- 
gen elimination  and  tlie  respiratory  gas-exchange  in  conjunction  with  the 
simultaneous  formation  of  heat. 

As  we  are  agreed  that  carbohydrates,  glycogen,  as  well  as  sugar,  can  be 
formed  from  proteids,  we  cannot  deny  the  fact  that  possibly  an  indirect 
formation  of  fat  from  proteids,  with  a  carbohydrate  as  an  intermediate  step, 
can  take  place.  The  possibility  of  a  direct  fat  formation  from  proteids  with- 
out the  carbohydrate  as  intermediary  must  also  be  generally  admitted,  al- 
though such  a  formation  has  not  been  conclusively  proved. 

According  to  Chauveau  and  Kaufmann,  in  the  direct  formation  of  fat 
from  proteids  the  fat  is  formed,  besides  urea,  carbon  dioxide,  and  water,  as  an 
intermediary  product  in  the  oxidation  of  the  proteids,  while  Gautier  con- 
siders tlie  formation  of  fat  from  proteids  as  a  cleavage  without  taking  up 
oxygen.     Drechsel*  has  called  attention  to  the  fact  that  the  proteid  mole- 

'Voit,  MUncb.  med.  "Wocheiischr.,  1892,  cited  from  Maly's  Jabresber.,  Bd.  22; 
Cremer,  Muncb.  med.  Wocbenscbr.,  1897;  Pfluger  in  Pflliger's  Arcb.,  Bd.  68. 

*In  regard  to  Ibe  question  as  to  tbe  formation  of  fat  from  proteid  in  tbe  animal  body 
see  Communications  of  tbe  Med.  Faculty  of  tbe  Imperial  University  of  Japan,  Tokio, 
Vol.  3,  1894. 

'Kaufmanu,  Arch,  de  Pbysiol.  (5),  Tome  8,  ^vbicb  also  cites  tbe  works  of  Chauveau 
and  Gautier. 

^Ladenburg's  HandwSrterbucb  der  Cbem.,  Bd.  3,  S.  543. 


330  TISSUES   OF  THE   CONNECTIVE  SUBSTANCE. 

cule  probably  origiually  contains  no  radical  with  more  than  six  or  nine  carbon 
atoms.  If  fat  is  formed  from  proteid  in  the  animal  body,  then,  according 
to  Drechsel,  such  formation  is  not  a  splitting  off  of  fat  from  the  proteids, 
but  rather  a  synthesis  from  primarily  formed  cleavage  products  of  proteids 
which  are  deficient  in  carbon. 

The  formation  of  fat  from  carbohydrates  in  the  animal  body  was  first 
suo-gested  by  Liebig.  This  was  combated  for  some  time,  and  until  lately  it 
was  the  general  oj)inion  that  a  direct  formation  of  fat  from  carbohydrates 
had  not  been  proved,  but  also  that  it  was  improbable.  The  undoubtedly 
great  influence  of  the  carbohydrates  on  the  formation  of  fat  as  observed  and 
proven  by  Liebig  was  explained  by  the  statement  that  the  carbohydrates 
were  consumed  instead  of  the  absorbed  fat  or  that  derived  from  the  proteids, 
hence  they  have  a  sparing  action  on  the  fat.  By  means  of  a  series  of  nutri- 
tion experiments  with  foods  especially  rich  in  carbohydrates,  Lawes  and 
Gilbert,  Sohxlet,  Tscherwinskt,  Meissl  and  Stromer  (on  pigs),  B. 
ScHULTZE,  Chaniewski,  E.  Voit  and  C.  Lehmann  (on  geese),  I.  Munk 
and  M.  EuBisrSR  and  Lummert'  (on  dogs)  apparently  prove  that  a  direct 
formation  of  fat  from  carbohydrates  does  actually  occur.  The  processes  by 
which  tnis  formation  takes  place  are  still  unknown.  As  the  carbohydrates 
do  not  contain  as  complicated  carbon  chains  as  the  fats,  the  formation  of  fat 
from  carbohydrates  must  consist  of  a  synthesis,  in  which  the  group  CHOH 
is  converted  into  CH, ;  also  a  reduction  must  take  place. 

After  feeding  with  very  large  quantities  of  carbohydrates  the  relation- 
ship between  the  inspired  oxygen  and  the  expired  carbon  dioxide,  i.e.,  the 

CO 
respiratory  quotient  -j^,  ^>'^a  found  greater  than  1  in  certain  cases  (Han- 
riot  and  RiGHET,  Bleibtreu,  Kaufmann,  Laulanie').  This  is  explained 
by  the  assumption  that  the  fat  is  formed  from  the  carbohydrate  by  a  cleavage 
setting  free  carbon  dioxide  and  water  without  taking  up  oxygen.  This  in- 
crease in  the  respiratory  quotient  also  depends  in  part  on  the  increased  com- 
bustion of  the  carbohydrate  (see  Chapter  XVIII). 

When  food  contains  an  excess  of  fat  the  superfluous  amount  is  stored  up 
in  the  fatty  tissue,  and  on  partaking  of  food  deficient  in  fat  this  accumula- 
tion is  quickly  exhausted.     There  is  perhaps  not  one  of  the  various  tissues 


'  Lawes  and  Gilbert,  Phil.  Transactions,  1859,  part  2;  Soxblet.  see  Maly's  Jahresber., 
Bd.  11,  S.  51;  Tscberwinsky,  Landwirtbsch.,  Versuchsstaat,  Bd.  29  (cited  from  Maly's 
Jahresber.,  Bd.  1.3);  Meissl  and  Stromer,  Wien.  Sitzuiig.sber.,  Bd.  88,  Abtb.  3;  Schultze, 
Maly's  .Tabresber.,  Bd.  11,  S.  47;  Cbanicwski,  Zeitscbr.  f.  Biologic,  Bd.  20;  Voit  and 
Lehman II,  see  C.  v.  Voit,  Silzungsber.  d.  k.  bayer.  Akad.  d.  Wissenscb.,  1885;  I.  Munk, 
Virchow's  Arch.,  Bd.  101;  Rubner,  Zeitschr.  f.  Biologic,  Bd.  22;  Lumraert,  PflUger's 
Arch.,  Bd.  71. 

•Hanriot  and  Richet,  Annal.  de  Chira.  et  de  Phys.  (6).  Tome  22;  Bleibtreu,  Pfliiger's 
Arch,,  Bd.  56;  Kaufmann,  Arch,  de  Physiol.  (5),  Tome  8;  Laulanie,  ibid.,  p.  791. 


FORMATION  OF  FAT.  '6'6l 

that  decreases  so  much  iu  starvation  as  the  facty  tissue.  Tlie  orgauism,  theu, 
possesses  in  this  tissue  a  depot  where  there  is  stored  during  proper  alimenta- 
tion a  nutritive  substance  of  great  importance  in  the  development  of  heat 
and  vital  force,  which  substance,  on  insufficient  nutrition,  is  given  olf  as 
may  be  needed.  On  account  of  their  low  conducting  power  the  fatty  tissues 
become  of  great  importance  in  regulating  the  loss  of  heat  from  the  body. 
They  also  serve  to  till  cavities  and  aa  a  protection  and  support  to  certain  in- 
ternal organs. 


CHAPTER  XL 

MUSCLE. 

Striated  Muscles. 

In  the  study  of  the  muscles  the  chief  problem  for  physiological  chem- 
istry is  to  isolate  their  different  morphological  elements  and  to  investigate 
each  element  separately.  By  reason  of  the  complicated  structure  of  the 
muscles  this  has  been  thus  far  almost  impossible,  and  we  must  be  satisfied 
at  the  present  time  with  a  few  micro-chemical  reactions  in  the  investi- 
gation of  the  chemical  composition  of  the  muscular  fibres. 

Each  muscle-tube  or  muscle-fibre  consists  of  a  sheath,  the  saecolemma, 
which  seems  to  be  composed  of  a  substance  similar  to  elastin,  and  con- 
taining/a large  proportion  of  pkoteid.  This  last,  which  in  life  possesses 
the  power  of  contractility,  has  in  the  inactive  muscle  an  alkaline  reaction, 
or,  more  correctly  speaking,  an  amphoteric  reaction  with  a  predominating 
action  on  red  litmus-paper.  RoHMANisr  has  found  that  the  fresh,  inactive 
muscle  shows  an  alkaline  reaction  with  red  lacmoid,  and  an  acid  reaction 
with  brown  turmeric.  Prom  the  behavior  of  these  coloring  matters  with 
various  acids  and  salts  he  concludes  that  the  alkalinity  of  the  fresh  muscle 
with  lacmoid  is  due  to  sodium  bicarbonate,  diphosphate,  and  probably  also 
to  an  alkaline  combination  of  proteid  bodies,  and  the  acid  reaction  with 
turmeric,  on  the  contrary,  to  monophosphate  chiefly.  The  dead  muscle  lias 
an  acid  reaction,  or  more  correctly  the  acidity  with  turmeric  increases  on  tlie 
decease  of  the  muscle,  and  the  alkalinity  with  lacmoid  decreases.  The 
difference  depends  on  the  presence  of  a  larger  quantity  of  monophosphate 
in  the  dead  muscle,  and  according  to  Eohmann  free  lactic  acid  is  found 
in  neither  the  one  case  nor  the  other.' 

If  we  disregard  the  somewhat  disputed  statements  relative  to  the  finer 
structure  of  the  muscles,  we  can  differentiate  in  the  striated  muscles 
between  the  two  chief  components,  the  doubly  refracting — anisotropous — 
and  the  singly  refracting — i.wtrojwiis — substance.  If  the  muscular  fibres 
are  treated  with  reagents  which  dissolve  proteids,   such  as  dilute  liydro- 

'  The  various  theories  in  regard  to  tlie  reaction  of  tlie  muscles  and  the  cause 
thereof  are  conflicting.  See  Rchmann,  Pflilger's  Arch.,  Bdd.  50  and  55  ;  Ileflfter,  Arch. 
f.  exp.  Path.  u.  Pharm.,  Bdd.  31  and  38. 

332 


PliOTEIDS  OF  TUB  MUSCLES.  333 

chloric  acid,  soda  solution,  or  gastric  juice,  they  swell  greatly  and  break  up 
into  "  Bowman's  c?js^-5."  By  the  action  of  alcohol,  chromic  acid,  boiling 
water,  or  in  general  such  reagents  as  cause  a  shrinking,  tlie  fibres  split 
longitudinally  into  fibrils;  and  this  behavior  shows  that  several  cheniicully 
different  substances  of  various  solubilities  enter  into  the  construction  of  the 
muscular  fibres. 

The  proteid  myosin  is  generally  considered  £is  the  chief  constituent  of  the 
diagonal  disks,  while  the  isotropous  substance  contains  the  chief  mass  of  the 
other  protoids  of  the  muscles  as  well  as  the  cliief  jiortion  of  the  extractives. 
According  to  the  observations  of  Danilewsky,  recently  confirmed  by 
J.  Holmgren,'  myosin  may  be  completely  extracted  from  the  muscle  with- 
out changing  its  structure,  by  means  of  a  bfo  solution  of  ammonium 
chloride.  Danilewsky  claims  'that  another  proteid-like  substance,  insolu- 
ble in  ammonium  chloride  and  only  swelling  up  therein,  enters  essentially 
into  the  structure  of  the  muscles.  Ti:e  proteids,  which  form  the  chief  part 
of  the  solids  of  the  muscles,  are  of  the  greatest  importance. 

Proteids  of  the  Muscles. 

Like  the  blood  which  contains  a  fluid,  the  blood-plasma,  which  sponta- 
neously coagulates,  separating  fibrin  and  yielding  blood-serum,  so  also  the 
living  muscle  contains,  as  first  shown  by  Kuhne,  a  spontaneously  coagu- 
lating liquid,  the  muscle-plasma,  which  coagulates  quickly,  separating  a 
proteid  body,  myosin,  and  yielding  also  a  serum.  That  liquid  which  is  ob- 
tained by  pressing  the  living  muscle  is  called  muscle-plasma,  while  that 
obtained  from  the  dead  muscle  is  called  muscle-serum.  These  two  fluids 
contain  different  albuminous  bodies. 

Muscle-plasma  was  first  pre^iared  by  Kuhne  from  frog-muscles,  and 
later  by  Halliburton,  according  to  the  same  method,  from  the  muscles  of 
warm-blooded  animals,  especially  rabbits.  The  principle  of  this  method  is 
as  follows:  The  blood  is  removed  from  the  muscles  immediately  after 
the  death  of  the  animal  by  passing  through  them  a  strongly  cooled  common- 
salt  solution  of  5-6  p.  m.  Then  the  quickly  cut  muscles  are  immediately 
thoroughly  frozen  so  that  they  can  be  ground  in  this  state  to  a  fine  mass — 
*' muscle-snow."  This  pulp  is  strongly  pressed  in  the  cold,  and  the  liquid 
which  exudes  is  called  muscle-plasma.  According  to  v.  Furth'  this  cooling 
or  freezing  is  not  necessary.  It  is  sufficient  to  extract  the  muscle  free  from 
blood,  as  above  directed,  with  a  6  p.  m.  common-salt  solution. 

Muscle-plasma  forms  a  yellow  to  brownish-colored    fluid  with  a  strong 

'  Dauilewsky,  Zeitschr.  f.  physiol.  Chem.,  Bd.  7;  J.  Holmgren,  Maly's  Jahresber., 
Bd.  23. 

*  See  Kiibne,  Untersuchungeu  ilber  das  Protoplasma  (Leipzig,  1864),  S.  2  ;  Hallibur- 
ton,  Journ.  of  Pbysiol.,  Vol.  S  ;  v.  Furth,  Arcb.  f.  exp.  Path.  u.  Pbarm.,  Bd.  36. 


334  MUSCLE. 

alkaline  reaction.  It  is  somewliat  different  in  different  animals.  Muscle- 
plasma  from  the  frog  spontaneously  coagulates  slowly  at  a  little  above  0°  0., 
but  quicker  at  the  temperature  of  the  body.  Muscle-plasma  from  mammals 
coagulates,  according  to  v.  Furth,  even  slowly  at  the  temperature  of  the 
room.  According  to  Kuhne  and  v.  FiiRTH  the  reaction  remains  alkaline 
during  coagulation,  while  according  to  Halliburton  it  becomes  acid. 
According  to  the  older  views  the  clot  consists  of  globulin  and  myosin,  while 
V.  FuRTH  claims  that  it  consists  of  two  coagulated  proteids,  myosin  fibrin 
and  myogen  fibrin.  As  the  study  of  the  proteids  of  the  muscles,  as  well  as 
their  nomeclature,  has  been  somewhat  developed  in  the  last  few  years,  it  is 
necessary  to  separately  discuss  the  proteids  of  the  dead  muscles  as  well 
as  those  of  the  muscle-plasma. 

The  proteids  of  the  dead  muscles  are  in  part  soluble  in  water  or  dilute 
salt  solutions,  and  part  are  insoluble  therein.  Myosin,  musculin,  myoglobu- 
lin,  and  myoalbumin  belong  to  the  first  group,  and  the  stroma  substances 
of  the  muscle-tubes  belong  to  the  second  group. 

Myosin  was  first  discovered  by  Kuhne,  and  constitutes  the  principal 
mass  of  the  soluble  proteids  of  the  dead  muscle,  and  is  generally  considered 
as  the  most  essential  coagulation  product  of  muscle-plasma.  With  the 
name  myosin  Kuhne  also  designates  the  mother-substance  of  the  plasma- 
clot,  and  this  mother-substance  forms,  according  to  certain  investigators, 
the  chief  mass  of  contractile  protoplasm.  The  statements  as  to  the  occur- 
rence of  myosin  in  other  organs  besides  the  muscles  require  further  proof. 
The  quantity  of  myosin  in  the  muscles  of  different  animals  varies,  according 
to  Danilewskt,'  between  30  and  110  p.  m. 

Myosin,  as  obtained  from  dead  muscles,  is  a  globulin  whose  elementary 
composition,  according  to  Chittenden  and  Cummins,^  is,  on  an  average, 
the  following:  C  52.82,  H  7.11,  N  16.17,  S  1.27,  0  22.03^.  If  the  myosin 
separates  as  fibres,  or  if  a  myosin  solution  with  a  minimum  quantity  of 
alkali  is  allowed  to  evaporate  on  a  microscope-slide  to  a  gelatinous  mass, 
doubly  refracting  myosin  may  be  obtained.  Myosin  has  the  general  prop- 
erties of  the  globulins.  It  is  insoluble  in  water,  but  soluble  in  dilute  saline 
solutions  as  well  as  dilute  acids  or  alkalies,  which  readily  converts  it  into 
albuminates.  It  is  completely  precipitated  by  saturating  with  NaCl,  also 
by  MgSO,,  in  a  solution  containing  94^  of  the  salt  with  its  water  of 
crystallization  (Halliburton).  Like  fibrinogen  it  coagulates  at  +  56°  C. 
in  a  solution  containing  common  salt,  but  differs  from  it  since  under  no  cir- 
cumstances can  it  be  converted  into  fibrin.  The  coagulation  temperature, 
according  to  Chittenden  and  Cummins,  not  only  varies  for  myosin  of  dif- 
ferent origin,  but  also  for  the  same  myosin  in  different  salt  solutions. 


'  Zeitschr.  f.  pliysiol.  Cbem.,  Bd.  7. 

'^  Studies  from  the  Physiol.  Chera.  Laboratory  of  Yale  College,  New  Haven,  Vol.  3,. 
p.  115. 


MYOSIN  AND  MUSCULIN.  335 

Myosin  may  be  prepared  in  the  following  way,  as  suggested  by  Halli- 
burton: The  muscle  is  first  extracted  by  a  bfc  magnesium-sulphate  solu- 
tion. The  filtered  extract  is  then  treated  with  ma.frnesium  sulphate  in  sub- 
stance until  100  c.c.  of  the  liquid  contains  about  50  grms.  ol'  the  salt.  Tlio 
so-called  paramyosinogen  or  musculin  separates.  The  filtered  lic|uid  is  then 
treated  with  magnesium  sulphate  until  each  100  c.c.  of  the  liquid  holds  !»4 
grms.  of  the  salt  in  solution.  The  myosin  Avhich  now  separates  is  filtered 
off,  dissolved  in  water  by  aid  of  the  retained  salt,  precipitated  by  diluting 
with  water,  and,  when  necessary,  purified  by  redissolving  in  dilute-salt  solu- 
tion and  precipitating  with  water. 

The  older  and  perhaps  the  usual  method  of  preparation  consists,  accord- 
ing to  Daxilewsky,'  in  extracting  the  muscle  with  a  5-10^  ammonium- 
chloride  solution,  precipitating  the  myosin  from  the  filtrate  by  strongly 
diluting  witli  water,  redissolving  the  preci[)itate  in  ammonium-chloride 
solution,  and  the  myosin  obtained  from  this  solution  is  either  reprecipitated 
by  diluting  with  water  or  by  removing  the  salt  by  dialysis. 

Musculin,"  called  paramyosinogen"  by  Halliburton,  and  myosin  by  v, 
FuRTH,  is  a  globulin  which  is  characterized  by  its  low  coagulation  tempera- 
ture, about  -f  47°  C,  which  may  vary  in  different  species  of  animals  (-(-  45° 
in  frogs,  -(-51°  C.  in  birds).  It  is  more  easily  precipitated  than  myosin  by 
NaCl  or  MgSO^  (salt  containing  50^  water  of  crystallization).  According  to 
v.  FiJRTH  it  is  precipitated  by  ammonium  sulphate  with  a  concentration  of 
12-24  p.  m.  If  the  dead  muscle  is  extracted  with  -water  a  part  of  the  musculin 
goes  into  solution  and  may  be  precipitated  therefrom  by  carefully  acidifying. 
It  separates  from  a  dilute  salt  solution  on  dialysis.  Musculin  readily  passes 
into  an  insoluble  modification  which  v.  Furth  calls  myosiJiUhrin.  Musculin 
is  called  myosin  by  v.  FQrth,  as  he  considers  it  nothing  but  myosin.  As 
musculin  has  a  lower  coagulation  temperature  and  has  other  precipitating 
properties  for  neutral  salts  than  the  older  substance  called  myosin,  it  is 
difticiilt  to  concede  to  this  view. 

MyoglobuUn.  After  the  separation  of  the  musculin  and  the  myosin  from 
the  salt  extract  of  the  muscle  by  means  of  MgSO^  the  myoglobulin  may  be 
precipitated  by  saturating  the  filtrate  with  the  salt.  It  is  similar  to  ser- 
globulin,  but  coagulates  at  +  63°  C.  (Halliburton).  Myoalbtimin,  or 
muscle-albumin,  seems  to  be  identical  with  seralbumin  (seralbumin  a,  accord- 
ing to  Halliburton),  and  probably  only  originates  from  the  blood  or  the 
lymph.     Albumoses  and  peptone  do  not  seem  to  exist  in  the  fresh  muscles. 

After  the  complete  removal  from  the  muscle  of  all  proteid  bodies  which 
are  soluble  in  water  and  ammonium  chloride,  an  insoluble  proteid  remains 
which  only  swells  in  ammonium-chloride  solution  and  which  forms  w-ith  the 
other  insoluble  constituents  of  the  muscular  fibre  the  "  muscle-stroma." 


'  Zeitscbr.  f.  physiol.  Cbem.,  Bd.  8,  S.  158. 

'  As  we  have  up  to  the  present  no  conclusive  basis  for  tbe  identity  of  tbe  globulins 
called  myosin  and  paramyosinogen,  and  also  as  the  use  of  tbe  name  myosin  for  tbe  last- 
mentioned  substance  may  readily  cause  confusion,  tbe  Acthor  does  not  feel  justified 
in  dropping  tbe  old  name  musculin  (Nasse). 


386  MUSCLE. 

According  to  Danilewsky  the  amount  of  such  stroma  substance  is  con- 
nected with  the  muscle  activity.  He  maintains  that  the  muscles  contain  a 
greater  amount  of  this  substance,  compared  with  the  myosin  present,  when 
the  muscles  are  quickly  contracted  and  relaxed. 

According  to  J.  Holmgren'  this  stroma  substance  does  not  belong^to  either 
the  nucleoalbumin  or  the  nucleoproteid  grouj).  It  is  not  a  glycof)roteid,  as 
it  does  not  yield  a  reducing  substance  when  boiled  with  dilute  mineral  acids. 
It  is  very  similar  to  coagulated  jDroteids  and  dissolves  in  dilute  alkalies,  form- 
ing an  albuminate.  The  elementary  composition  of  this  substance  is  nearly 
the  same  as  that  of  myosin.  There  is  no  doubt  that  the  insoluble  substa-nces, 
myofibrin  and  myosinfibrin,  which  are  formed,  according  to  v.  Furth,  in  the 
coagulation  of  the  plasma,  occur  also  among  the  stroma  substances.  When 
the  muscles  are  previously  extracted  with  water  the  stroma  substance  also 
contains  a  part  of  the  myosin  hereby  made  insoluble.  To  the  proteids  in- 
soluble in  water  and  neutral  salt  belongs  the  nucleoproteid  detected  by 
Pekelharing,^  and  occurring  as  traces  and  soluble  in  faintly  alkaline  water, 
and  which  originates  probably  from  the  muscle  nuclei. 

Muscle-syntonin,  which  may  be  obtained  by  extracting  the  muscles  with  hydro- 
chloric acid  of  1  p.  m.,  and  which,  according  to  K.  Morner,  is  less  soluble  and  has  a 
greater  a^ptitude  to  precipitate  than  other  acid  albumins,  seems  not  to  occur  preformed  in 
the  muscles. 

Proteids  of  the  Muscle-plasma.  As  above  stated,  we  consider  as  myosin 
the  coagulated  modification  of  the  soluble  proteid  existing  in  the  muscle- 
plasma.  As  in  blood-plasma  we  have  a  mother-substance  of  fibrin,  fibrinogen, 
so  also  there  exists  in  the  muscle-plasma  a  mother-substance  of  myosin,  a 
soluble  myosin  or  a  myosinogen.  This  body  has  not  thus  far  been  isolated 
with  certainty.  Halliburton,  who  has  detected  in  the  muscles  an  enzyme- 
like  substance,  "  myosin- ferment, '"*  ^vhich  is  related  but  not  identical  with 
fibrin-ferment,  has  also  found  that  a  solution  of  purified  myosin,  in  dilute-salt 
solution  (5^  MgSOJ,  and  sufficiently  diluted  with  water,  coagulates  after  a 
certain  time,  and  at  the  same  time  becomes  acid,  and  a  typical  myosin-clot 
separates.  This  coagitlation,  which  is  accelerated  by  warming  or  by  the 
addition  of  myosin-ferment,  is,  according  to  Halliburton,  a  process  analo- 
gous to  the  coagulation  of  the  muscle-plasma.  According  to  this  same  in- 
vestigator, myosin  when  dissolved  in  water  by  the  aid  of'  a  neutral  salt  is 
reconverted  into  myosinogen,  while  after  diluting  with  water  myosin  is  again 
produced  from  the  myosinogen.  No  definite  conclusion  can  be  drawn  from 
these  observations. 

Besides  the  traces  of  globulin  and  albumin,  which  perhaps  do  not  belong 
to  the  muscle-plasma,  we  find  in  mammals,  according  to  v.  Furth,  two  pro- 
teids, namely,  musculin  (myosin  according  to  v.  Furth)  and  myogen. 

'  See  Danilewsky  and  Holmgren,  foot-note  1,  page  333. 
'Zeitschr.  f.  physiol.  Chem.,  Bd.  22. 


MTOOEN.  337 

MuscuLiN  (Nasse)  =  paramyosinogen  (Halliburton)  =  myosin  (v. 
FCrtii)  forms  about  20^  of  the  total  proteids  of  the  mu8cle-])lasma  of 
rul)bits.  Its  properties  have  already  been  given,  and  it  is  sufficient  to 
remark  that  its  solutions  become  cloudy  on  standing,  and  a  precipitate  of 
nn/o.si)i-fiOrin  occurs,  which  is  insoluble  in  salt  solutions. 

Myogen,  or-MYOSiNOGEN  (Halliburton),  forms  the  chief  mass,  75-80,^  of 
tiie  proteids  of  rabbit-muscle  plasma.  It  does  not  separate  from  its  solu- 
tions on  dialysis  and  is  not  a  true  globulin,  but  a  proteid  sni  gpyieris.  It 
coagulates  at  55-56°C.  and  is  precipitated  in  the  presence  of  24-40^  ammo- 
nium sulphate.  Myogen  solutions  are  precipitated  by  acetic  acid  only  in  the 
presence  of  some  salt.  It  is  converted  into  an  albuminate  by  alkalies,  this 
albuminate  being  precipitable  by  ammonium  chloride.  Myogen  passes 
spontaneously,  especially  with  higher  temperatures  as  well  as  in  the  presence 
of  salt,  into  an  insoluble  modification,  my og en-fibrin.  A  proteid,  coagulating 
at  30-40°  C,  soluble  my  og  en-fibrin  is  produced  as  soluble  intermediate  step. 
This  substance  occurs  to  a  considerable  extent  in  native  frog-muscle  plasma. 
It  does  not  always  occur  in  the  muscle-plasma  of  warm-blooded  animals,  and 
when  it  does  it  is  present  only  to  a  slight  extent.  It  can  be  separated  by 
precipitating  with  salt  or  by  diffusion.  Halliburton's  assumption  as  to 
the  action  of  a  special  myosin  ferment  has  not  sufficient  basis,  according  to 
V.  FuRTii,  nor  has  the  often-admitted  analogy  with  the  coagulation  of  the 
"blood.  The  difference  between  the  musculin  and  the  myogen  becoming 
insoluble  is  that  the  musculin  passes  into  nijosin-fibrin  without  any  soluble 
intermediate  steps. 

Myogen  may  be  prepared,  according  to  v.  Furth,  by  transiently  heating 
the  dialysed  and  filtered  plasma  to  52°  C,  separating  it  in  this  way  from  the 
rest  of  the  musculin.  The  myogen  exists  in  the  new  filtrate  and  can  be 
precipitated  by  ammonium  sulphate.  The  musculin  may  also  be  removed 
by  adding  28;^  ammonium  sulphate  and  then  precipitating  the  myogen  from 
the  filtrate  by  saturating  with  the  salt. 

If  the  myogen,  as  v.  FiJRTH  claims,  is  no  glo^alin  it  cannot  be  identical 
with  Halliburton's  myosinogen,  and  it  is  also  difficult  to  bring  the  myogen 
in  certain  relationship  to  Kuhne's  myosin,  which  is  also  a  globulin.  As  muscu- 
lin (paramyosinogen)  does  not  yield  any  myosin  clot  on  coagulation,  and  as  it 
differs  from  Kuhne's  myosin  from  dead  muscles  in  coagulation  temperature 
as  well  as  precipitation  properties,  it  is  hardly  possilile  to  bring  the  experi- 
ence of  the  older  investigators  into  accord  with  the  observations  of  v.  Furth, 
and  hence  further  researches  on  this  subject  are  greatly  to  be  desired. 

Myoproteid  is  a  proteid  found  by  v.  Furth  in  the  plasma  from  fish- 
muscles.  It  does  not  coagulate  on  boiling,  is  precipitated  by  acetic  acid,  and 
considered  as  a  compound  proteid  by  v.  Furth. 

Muscle-pigments.  There  is  no  question  that  the  red  color  of  the  muscles 
even  when  completely  freed  from  blood  depends  in  part  on  haemoglobin. 


338  MUSCLE. 

K.  MOenee  has  shown  that  muscle  haemoglobin  is  not  identical  with  blood- 

hsemoglobin.     The  statement    of  MacMunn  that  in  the  muscles  another 

pigment  occurs  which  is  allied  to  haemochromogen  and  called  myohwmatin 

by  him  has  not  been  substantiated,  at  least  for  muscles  of  higher  animals 

(Levy  and  MoR^STER^).     MacMukx  claims  that  myohrematin  occurs  in  the 

muscles  of  insects,  which  do  not  contain  any  haemoglobin. 

The  reddish-yellow  coloriug  matter  of  the  muscles  of  the  salmon  has  been  little 
studied.  Traces  of  enzymes,  such  as  pepsin  and  dias?atic  enzymes,  have  been  found  in 
them.  The  so-called  "  myosin-ferment,"  and  probably  an  enzyme  producing  lactic-acid 
fermentation,  are  also  found  in  these  muscles. 

Extractive  Bodies  of  the  Muscles. 

The  nitrogenous  extractives  consist  chiefly  of  creatin,  on  an  average  of 
1-4  p.  m.,  in  the  fresh  muscles  containing  water,  also  the  xanthin  bodies, 
hyjwxatithin  and  xantliin,  besides  guanin  and  carnin.  The  average  quanti- 
ties of  liypoxanthin,  xanthin,  and  guanin  in  1000  parts  of  the  dried  sub- 
stance of  the  muscles  of  oxen  are,  according  to  Kossel,''  respectively  2.30, 
0.53,  and  0.20  grms.,  and  in  the  embryonic  ox- muscles  respectively  3.59, 
1.11,  and  4.12  grms. 

Among  the  habitually  occurring  nitrogenous  extractives  we  should  men- 
tion 2^1iospliocarnic  acid  and  also  inosinic  acid,  which  is  perhaps  allied  to  it. 

Amjong  the  extractive  substances  we  also  find  the  acid  found  by  Limpricht  in  the 
flesh  of  certain  cyprindea,  namely,  the  nitrogenized  protic  acid  and  isocreatinin "  found 
by  J.  Thesen  in  fish-flesh.  Uric  acid,  urea,  taurin,  and  leucin  are  found  as  traces  in 
the  muscles,  in  certain  cases  only,  of  a  few  species  of  animals.  In  regard  to  the 
amount  of  these  difiierent  extractives  in  the  muscles,  Krukenbekg  and  Wagner  *  have 
shown  that  it  varies  greatly  iu  different  animals.  A  large  quantity  of  urea  is  found  iu 
the  muscles  of  the  shark  and  ray;  uric  acid  is  found  in  alligators;  taurin  in  cephalopoda; 
glycocoll  in  mollusks,  pecten irradians;  and  creatininin  luvarus  iniperialis,  etc.,  etc.  The 
reports  are  very  contradictory  in  regard  to  the  occurrence  of  urea  in  the  muscles  of 
higher  animals  According  to  the  recent  investigations  of  Kaupmann  and  Schondorff 
urea  is  a  regular  constituent  of  the  muscles,  vrhile  M.  Nencki  and  Kowarski'  claim 
that  this  is  not  so.  Schondorff «  has  prepared  urea  in  substance  from  the  muscles  of  dogs 
and  cats  and  identified  it  by  elementary  analysis.  The  quantity  of  urea  in  the  muscles 
was  on  an  average  of  0.884  p.  m. 

The  xanthin  bodies,  with  the  exception  of  carnin,  liave  been  treated  on 
pages  llG-121,  and  therefore  among  tlie  extractive  bodies  we  will  first 
consider  the  creatin. 

Creatin,  C,II,N,0,  +  11,0,  or  methylguanidin- acetic  acid,  NH  : 
C(Nn,).N(Cn3).ClI,.C00II  +  H,0,  occurs  in  the  muscles  of   vertebrate 

"See  MacMunn,  Phil.  Trans,  of  Roy.  Soc,  Vol.  177,  part  1,  Jouru  of  Pliysiol., 
Vol.  8,  and  Zeitschr.  f.  physiol.  Cheni.,  Bd.  13;  Levy,  ibid.,  Bd.  13;  K.  MoRNER,  Nord. 
Med.  Archiv.  Fcslband,  1897,  and  Maly's  Jahresber.,  Bd.  27. 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  8,  S.  408. 

'See  Limpricht,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  127;  and  Thesen,  Zeitschr.  f. 
physiol.  Chem.,  Bd.  24. 

•*  Zeitschr.  f.  Biologic,  Bd.  21. 

■  Kaufmann,  Arch,  de  Physiol.,  (5)  Tome  6  ;  Schondorff,  Pflliger's  Arch.,  Bd.  62  ; 
Nencki  and  Kowarski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  36. 

•PflUger's  Arch.,  Bd.  74. 


CREA  TIN.  339 

animals  in  variable  amounts  in  dilTereut  species  ;  the  largest  quantity   is 

found  in  birds.     It  is  also  found  in  the  brain,  blood,  transudations,  and  the 

amniotic  fluid,     Creatin  may  be  prepared  synthetically  from  cyanamid  and 

sarcosin  (methylglycocoll).     On  boiling  with  baryta-water  it   decomposes, 

with   the  addition  of   water,  and  yields  urea,   sarcosin,   and  certain  other 

products.     Because  of  this  behavior  several  investigators  consider  creatin  as 

a  step  in  the  formation  of  urea  in  the  organism.     On  boiling  with  acids 

creatin   is  easily  converted,  with  the  elimination  of  water,  into  creatinin, 

C^H,N,0,  which  occurs  in  urine,   and  which  has  also  been  found  in  the 

muscles  of  the  dog  by  Moxari  '  (see  Chapter  XV). 

According  to  St.  Johnson  no  creatin  occurs  in  the  fresh  flesh  of  oxen,  but  a  crea- 
tinin, differing  from  that  found  in  urine  ;  but  this  statement  is  incorrect  according  to 

WOEKNEK.' 

Creatin  crystallizes  in  hard,  colorless,  monoclinic  prisms  which  lose  their 
water  of  crystallization  at  100°  C.  It  dissolves  in  74  parts  of  water  at  the 
ordinary  temperature  and  9410  parts  absolute  alcohol.  It  dissolves  more 
easily  with  the  aid  of  heat.  Its  watery  solution  has  a  neutral  reaction. 
Creatin  is  not  dissolved  by  ether.  If  a  creatin  solution  is  boiled  with 
precipitated  mercuric  oxide,  this  is  reduced,  especially  in  the  presence  of 
alkali,  to  mercury  and  oxalic  acid,  and  the  foul-smelling  methyluramin 
(methylguanidin)  is  developed.  A  solution  of  creatin  in  water  is  not  precipi- 
tated by  basic  lead  acetate,  but  gives  a  white,  flaky  precipitate  with  nier- 
curous  nitrate  if  the  acid  reaction  is  neutralized.  When  boiled  for  an  hour 
with  dilute  hydrochloric  acid  creatin  is  converted  into  creatinin,  and  mav 
be  identified  by  its  reactions. 

The  preparation  and  detection  of  creatin  is  best  performed  by  the  follow- 
ing method  of  Neubauer,"  which  was  first  used  in  the  preparation  of  crea- 
tin from  muscles:  Finely  cut  flesh  is  extracted  with  an  equal  weight  of  water 
at  +  55°  to  G0°  C.  for  10-15  minutes,  pressed  and  extracted  again  with 
water.  The  proteids  are  removed  from  the  united  extracts  as  far  as  possible 
by  coagulation  at  boiling  heat,  the  filtrate  jirecipitated  by  the  careful  addi- 
tion of  basic  lead  acetate,  the  lead  removed  from  this  filtrate  by  H  S  and 
carefully  concentrated  to  a  small  volume.  The  creatin,  which  crystallizes 
in  a  few  days,  is  collected  on  a  filter,  washed  with  alcohol  of  88,^,  and  puri- 
fied, when  necessary,  by  recrystallization.  The  quantitative  estimation  of 
creatin  is  performed  according  to  the  same  method. 

Isocreatinin,  is  a  creatinin  isomeric  with  ordinary  creatinin  and  found  by  Thesen  * 
in  the  Hcsh  of  tlie  codfish.  It  crystallizes  in  yellow  needles  or  plates,  is  more  soluble  in 
cold  water,  but  more  insoluble  in  alcohol,  than  the  ordinary  creatinin,  and  gives  apicrate 
which  is  readily  soluble  and  a  zinc  chloride  combination  which  is  relatively  readily 
soluble.  It  gives  Weyl's  reaction  less  rapidly,  and  does  not  give  methylguanidin  on 
treatment  with  potassium  permanganate. 

'  Maly's  Jahresber.    Bd.  19,  S.  296. 

'Johnson,  Proc.  Roy.  Soc,  vols.  43,  50  ;  "Woerner,  Du  Bois-Reymond's  Arch.,  1898, 
and  Zeitschr.  f.  physiol.  Chem.,  Bd.  27. 
'Zeitschr.  f.  analyt.  Chem.,  Bdd.  2  and  6. 
*h.  c. 


340  MUSCLE. 

Carnin,  C^HgN^O,  +  H^O,  is  one  of  the  substances  found  by  Wp:idel  in 
American  meat  extract.  It  has  also  been  found  by  Kkukenberg  and 
Wagner  in  frog-muscles  and  in  the  flesh  of  fishes,  and  by  Pouchet  '  in  the 
urine.     Carnin  may  be  transformed  into  hypoxanthin  by  oxidation. 

Carnin  has  been  obtained  as  a  white  crystalline  mass.  It  dissolves  with 
difficulty  in  cold  water,  but  dissolves  easily  in  warm.  It  is  insoluble  in 
alcohol  and  ether.  It  dissolves  in  warm  hydrochloric  acid  and  yields  a  salt, 
crystallizing  in  shining  needles,  which  gives  a  double  combination  with 
platinum  chloride.  Its  watery  solution  is  precipitated  by  silver  nitrate,  but 
this  precipitate  is  dissolved  neither  by  ammonia  nor  by  warm  nitric  acid. 
Carnin  does  not  give  the  so-called  Weidel's  xanthin  reaction.  Its  watery 
solution  is  precipitated  by  basic  lead  acetate;  still  the  lead  combination  may 
be  dissolved  on  boiling. 

Carnin  is  prepared  by  the  following  method :  The  meat  extract  diluted 
with  water  is  completely  precipitated  by  baryta-water.  The  filtrate  is  jDre- 
cipitated  by  basic  lead  acetate,  the  lead  precipitate  boiled  with  water,  fil- 
tered while  hot,  and  sulphuretted  hydrogen  passed  through  the  filtrate. 
Remove  the  lead  sulphide  from  the  filtrate  and  concentrate  strongly.  The 
concentrated  solution  is  now  completely  precipitated  with  silver  nitrate,  the 
precipitate  washed  free  from  silver  chloride  by  ammonia,  and- the  carnin  sil- 
ver o;xide  suspended  in  water  and  treated  with  sulphuretted  hydrogen. 

Phospliocarnio  acid  ^  is  a  complicated  substance,  first  isolated  by  Siegfried  from  meat 
extracts,  which  yields  as  cleavage  products,  succinic  acid,  carbon  dioxide,  phosphoric 
acid,  iiiid  a  carbohydrate  group,  besides  the  previously  mentioned  carnic  acid.  It  stand-:, 
according  to  Siegfried,  in  close  relationship  to  the  nucleins,  and  as  it  yields  pep- 
tone (.carnic  acid),  it  is  designated  as  a  nucleoli  by  Siegfried.  Phosphocarnic  acid  may  be 
precipitated  as  an  iron  combination,  carniferrin,  from  the  extract  of  the  muscles  free 
from  proteids.  Ktjtscher  '  claims  that  carniferrin  cannot  be  a  unit  body  on  account  of 
its  method  of  preparation.  According  to  him  it  is  a  mixture  of  iron  combinations  of 
heterogeneous  l)odies.  The  quantity  of  phosphocarnic  acid,  calculated  as  carnic  acid,  can 
be  determined  by  multiplying  the  quantit}^  of  nitrogen  in  the  combination  by  the  factor 
6.1237  (Balke  and  Ide).  In  this  way  Siegfried  found  0.57-2.4  p.  m.  carnic  acid  in 
the  resting  muscles  of  the  dog,  and  M.  Mtjller  1-2  p.  m.  in  the  muscle  of  adults  and 
a  maximum  of  0.57  p.  m.  in  those  of  new-born  infants.  Phosphocarnic  acid  which  has 
not  been  prepared  pure  in  the  free  state  is,  according  lo  Siegfried,  a  source  of  energy 
in  the  muscles  and  is  consumed  during  work.  Besides,  by  means  of  its  property  of 
forming  soluble  salts  witli  the  alkaline  earths,  as  also  an  iron  combination  soluble  in 
alkalies,  it  serves  to  act  as  a  means  of  transportation  of  these  bodies  in  the  animal  body. 

Pliosphocarnic  acid  is  prepared  from  the  extract  free  from  proteid  by  first  removing 
the  phosphate  by  CaCla  and  NHa.  The  acid  is  precipitated  from  the  filtrate  while  boil- 
ing, as  carniferrin  by  ferric  chloride. 

Inosinic  Acid.  Tliis  acid  was  first  isolated  from  the  flesh  of  certain  animals  by  Lie- 
big  and  closely  studied  by  Haiser.*    It  contains  phosphorous,  is  amorphous,  and  gives 

'  Weidel,  Annal.  d.  Chein.  u.  Pharm.,  Bd.  158;  Wagner,  Sitzungsber.  d.  Wiirzb. 
phys.-med.  Gesellsch.,  1883;  Pouchet,  cited  from  Neubauer-Huppert,  Analyse  de8 
Harnes,  10.  Aufl.,  S.  335. 

'  In  regard  to  carnic  acid  and  phosphocarnic  acid  see  the  works  of  Siegfried,  Du  Bois- 
Reymond's  Arch.,  1894,  Ber.  d.  deutsch.  Chem.  Gesellsch.,  Bd.  28,  and  Zeitschr.  f.  phy- 
siol.  Chem.,  Bd.  21  ;  M.  Muller,  ibid.,  Bd.  22  ;  Kruger.  ibid.,  Bd.  22  ;  Balke  and  Ide, 
ibid.,  Bd.  21,  and  Balke,  ibid.,  Bd.  22. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

''Liebig,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  62  :  Haiser,  Monatshefte  f.  Chem.,  Bd.  16. 


INOSIT.  .  341 

crystalline  salts  with  barium  nud  calcium.  Its  formula  is  (",oH,jN4POb.  Haiseu  ob- 
taiiiuil  Jiyix^xuiithiii  as  a  cleava{,'e  i)roduct,  auii  probably  also  trioxyvaleriauic  acid,  al- 
thougli  it  was  not  positively  proved. 

We  must  also  include  amoug  the  nitrogenous  extractives  those  bodies 

which  were  first  discovered  by  Gautier'  and  whicli   occur  only  in  very 

small    quantities,    namely,   the    leucomaines,    xcmihocreatinin,    CjH,^N/J, 

crusocreatinin,  CjIIgN^O,  amphicreatini7i,  C,Ii,gN,0^,  and  pseudoxanihin, 

In  the  analysis  of  meat  and  for  the  detection  and  separation  of  tlie  vari- 
ous extractive  bodies  of  the  same  we  make  use  of  the  systematic  method  as 
suggested  by  Gautier,"  for  details  of  which  we  must  refer  the  reader  to  the 
original  article. 

The  non-nitrogenous  extractive  bodies  of  the  muscles  are  inosit,  ghjco- 
gen,  sugar,  and  lactic  acid. 

Inosit,  C,H,,0,  +  HjO.  This  body,  discovered  by  Scherer,  is  not  a 
carboliydrate,  but  belongs  to  the  aromatic  series  and  seems  to  be  hexahy- 
droxybenzol  (Maquexne").  AVith  hydriodic  acid  it  yields  benzol  and  tri- 
iodophenol.  Inosit  is  found  in  the  muscles,  liver,  spleen,  leucocytes,  kidneys, 
suprarenal  capsule,  lungs,  brain,  testicles,  and  in  tlie  urine  in  putliological 
cases,  and  as  traces  in  normal  urine.  It  is  found  very  widely  distributed  in 
the  vegetable  kingdom,  especially  in  unripe  fruits  and  in  green  beans  (pha- 
seolns  vulgaris),  and  therefore  it  is  also  called  phaseomanxit. 

Inosit  crystallizes  in  large,  colorless,  rhombic  crystals  of  the  nionocliuic 
system,  or,  if  not  pure  and  if  only  a  small  quantity  crystallizes,  it  forms 
grou})s  of  tine  crystals  similar  to  cauliflower.  It  loses  its  water  of  crystalli- 
zation at  110°  C,  also  if  exposed  to  the  air  for  a  long  time.  Such  exposed, 
crystals  are  non-transparent  and  milk-white.  The  crystals  melt  at  217°  C 
Inosit  dissolves  in  7.5  parts  of  water  at  ordinary  temperature,  and  the  solu- 
tion has  a  sweetish  taste.  It  is  insoluble  in  strong  alcohol  and  in  ether.  It 
dissolves  copper  oxyhydrate  in  alkaline  solutions,  but  does  not  reduce  on 
boiling.  It  gives  negative  results  with  Moore's  test  and  Avith  Bottger- 
Almen's  bismuth  test.  It  does  not  ferment  with  beer-yeast,  but  may  under- 
go lactic-  and  butyric-acid  fermentation.  The  lactic  acid  formed  thereby  is 
sarcolactic  acid  according  to  Hilger,  and  fermentation  lactic  acid  according 
to  VonL.*  Inosit  is  oxidized  into  rhodizonic  acid  by  an  excess  of  nitric  acid, 
and  the  following  reactions  depend  upon  this  behavior: 

If  inosit  is  evaporated  to  dryness  on  platinum-foil  with  nitric  acid  and 
the  residue  treated  with  ammonia  and  a  drop  of  calcium-chloride  solution, 
and  carefully  re-evaporated  to  dryness,  a  beautiful  rose-red  residue  is  ob- 

'  Maly's  Jahresbcr..  Bd.  16,  S.  523. 
*Jbid.,  Bd.  22,  8.  335. 

*Bull.  do  la  Soc.  cliim.  (2),  Tomes  47  and  48;  Comp.  rend.,  Tome  104. 
••Hilger,  Annal.  d.  Cbem.  u.  Pbarm.,  Bd.  160;  Vobl,  Ber.  d.  deutsch.  Chem.  Gesellsch., 
Bd.  9. 


342  MUSCLE. 

tained  (Scheree's  iuosit  test).  If  we  evaporate  an  inosit  solution  to  incipi- 
ent dryness  and  moisten  the  residue  with  a  little  mercuric-nitrate  solution, 
we  obtain  a  yellowish  residue  on  drying,  wliich  becomes  a  beautiful  red  on 
strongly  heating.  The  coloration  disappears  on  cooling,  but  it  reappears  on 
gently  warming  (Gallois's  iuosit  test). 

To  prepare  inosit  from  a  liquid  or  from  a  watery  extract  of  a  tissue,  the 
proteids  are  first  removed  by  coagulating  at  boiling  heat.  The  filtrate  is 
l^recipitated  by  sugar  of  lead,  this  filtrate  boiled  with  basic  lead  acetate  and 
allowed  to  stand  24-48  hours.  The  preciioitate  thus  obtained,  wliich  con- 
tains all  the  inosit,  is  decomposed  in  water  by  H„S.  The  filtrate  is  strongly 
concentrated,  treated  with  2-4  vols,  hot  alcohol,  and  the  liquid  removed  as 
soon  as  possible  from  tlie  tough  or  flaky  masses  which  ordinarily  separate. 
If  no  crystals  separate  from  the  liquid  within  24  hours,  then  treat  with  ether 
until  tlie  liquid  has  a  milky  appearance  and  allow  it  to  stand.  In  the  pi'es- 
ence  of  a  sufficient  quantity  of  ether,  crystals  of  inosit  separate  within  24 
hours.  The  crystals  thus  obtained,  as  also  those  which  are  obtained  from 
the  alcoholic  solution  directly,  are  recrystallized  by  redissolving  in  very  little 
boiling  water  and  the  addition  of  3-4  vols,  alcohol. 

Glycogen  is  a  constant  constituent  of  the  living  muscle,  while  it  may  be 
absent  in  the  dead  muscle.  The  quantity  of  glycogen  varies  in  the  different 
muscles yof  the  same  animal.  Bohm'  found  10  p.  m.  glycogen  in  the  muscles 
of  cats/ and  moreover  he  found  a  greater  amount  in  the  muscles  of  the  ex- 
tremities than  in  those  of  the  rump.  The  food  also  has  a  great  influence. 
BoiiM  found  1-4  p.  m.  glycogen  in  the  muscles  of  fasting  animals,  and  7-10 
p.  m.  after  partaking  of  food.  As  stated  in  Chapter  VIII,  lack  of  carbo- 
hydrates in  the  food  causes  the  glycogen  to  disapjaear  earlier  from  the  liver 
than  from  the  muscles. 

The  sugar  of  the  muscles,  of  which  traces  only  occur  in  the  living  muscle 
and  which  is  probably  formed  after  the  death  of  the  muscle  from  the  muscle- 
glycogen,  is,  according  to  the  investigations  of  Panormoff,'  probably  dex- 
trose. As  an  intermediate  step  in  this  sugar-formation  we  must  mention 
dextrin,  which  is  sometimes  found  in  the  muscles.  Perhaps  this  dextrin  has 
been  confounded  with  glycogen. 

Lactic  Acids.  Of  the  oxypropionic  acids  with  the  formula  C,HgO,  there 
is  one,  ]i5'dracrylic  acid,  CH,(0H).0H5.C00H,  which  is  not  found  in  the 
animal  body  and  therefore  has  no  physiological  chemical  interest.  Indeed 
only  ar-oxypropionic  acid  or  ethylidene  lactic  acid,  CH3.(0H).CHC00H,  of 
which  we  have  three  physical  isomers,  is  of  importance.  These  three  ethy- 
lidene lactic  acids  are  tlic  ordinary,  optically  inactive  fermentation"  lactic 
ACID,  the  dextro-rotatory  paralactic  or  sarcolactic  acid,  and  the  LiEVO- 
LACTic  ACID  obtained  by  Sciiardingek  by  the  fermentation  of  cane-sugar 
by  means  of  a  special  bacillus.     This  Isevolactic  acid  has  also  been  detected 

'  Pfluger's  Arch.,  Bd.  23,  S.  44. 
'Zeilschr.  f.  physiol.  Cbem.,  Bd.  17. 


LACTIC  ACIDS.  343 

by  Hlachstein  in  the  culture  of  Gaffky's  typhoid  bacillus  in  a  solutiou  of 
sugar  und  peptone,  ami  whicli  is  formed  by  various  vibriones,  need  not  be 
dcscrilx'd  liere.' 

'Y\\Q  fennentat ion  lactic  acid,  whicli  is  formed  from  tlie  milk-sugar  by 
allowing  milk  to  sour  and  by  the  acid  fermentation  of  other  carbohy- 
drates, is  considered  to  exist  in  small  quantities  in  the  muscles  (IIeixtz),  in 
the  gray  matter  of  the  brain  (Gscheidlen)/  and  in  diabetic  urine.  Durino- 
digestion  this  acid  is  also  found  in  the  contents  of  the  stomach  and  intestine, 
and  as  alkali  lactate  in  the  cliyle.  The  paralactic  acid  is,  at  all  events,  the 
true  acid  of  meat  extracts,  and  this  alone  has  been  found  with  certainty  in 
dead  muscle.  The  lactic  acid  which  is  found  in  the  spleen,  lymphatic  glands, 
thymus,  thyroid  gland,  blood,  bile,  pathological  transudations,  osteomalacious 
bones,  in  perspiration  in  puerperal  fever,  and  in  the  urine  after  fatiguing 
marches,  in  acute  yellow  atrophy  of  the  liver,  in  poisoning  by  phosphorus, 
and  especially  after  extirpation  of  the  liver,  seems  to  be  paralactic  acid. 

Tlie  origin  of  paralactic  acid  in  the  animal  organism  has  been  sought 
by  several  investigators,  who  took  for  basis  the  researches  of  Gaglio, 
Minkowski,  and  Araki,'  in  a  decomposition  of  proteid  in  tlie  tissues. 
Gaglio  claims  a  lactic-acid  formation  by  passing  blood  through  the 
kidneys  and  lungs.  He  also  found  0.3-0.5  p.  m.  lactic  acid  in  the  blood 
of  a  dog  after  proteid  food,  and  only  0.17-0.21  p.  m.  after  fasting  for  48 
hours.  According  to  Minkowski  the  quantity  of  lactic  acid  eliminated  by 
the  urine  in  animals  with  extirpated  livers  is  increased  with  proteid  food, 
while  tlie  administration  of  carbohydrates  has  no  effect.  Araki  has  also 
shown  tliat  if  we  produce  a  scarcity  of  oxygen  in  animals  (dogs,  rabbits,  and 
hens)  by  poisoning  with  carbon  monoxide,  by  the  inhalation  of  air  deficient 
in  oxygen,  or  by  any  other  means,  a  considerable  elimination  of  lactic  acid 
(besides  dextrose  and  also  often  albumin)  takes  place  through  the  urine. 
As  a  scarcity  of  oxygen,  according  to  the  ordinary  statements,  produces  an 
increase  of  the  proteid  katabolism  in  the  body,  the  increased  elimination  of 
lactic  acid  in  these  cases  must  be  due  in  part  to  an  increased  proteid 
destruction  and  in  part  to  a  diminished  oxidation. 

Araki  has  not  drawn  such  a  conclusion  from  his  experiments,  but 
he  considers  the  abundant  formation  of  lactic  acid  to  be  due  to  a  cleavage 
of  the  sugar  formed  from  the  glycogen.  He  found  that  in  all  cases  where 
lactic  acid  and  sugar  appeared  in  the  urine  the  quantity  of  glycogen  in  the 

'  See  Schardinger.  Monatshefte  f.  Chem..  Bd.  11;  Blaclistcin.  Arch,  des  sciences  biol. 
de  St.  Petersbourg.  Tome  1,  p.  199;  Kuprianow,  Arch.  f.  Hygiene,  Bd.  19,  and  Gosio, 
ibid.,  Bd.  21. 

'  Heintz,  Aunal.  d.  Chem.  u.  Pharm.,  Bd.  157,  and  Gscheidlen,  PflUger's  Arch.,  Bd. 
8,  S.  171. 

'  Gaglio.  Du  Bois-Reyniond's  Arch.,  1886  ;  Minkowski.  Arch.  exp.  Path.  u.  Pharm., 
Bdd.  21  and  31  ;  Araki.  Zeitsclir.  f.  physiol.  Chem.,  Bdd    LI.  16.  17.  and  19. 


344  .  MUSCLE. 

liver  and  muscles  was  always  diminished.  He  also  calls  attention  to 
the  fact  that  dextrolactic  acid  may  be  formed  from  glycogen,  as  directly 
observed  by  Ekuxixa/  and  also  to  the  numerous  observations  on  the 
formation  of  lactic  acid  and  the  consumption  of  glycogen  in  muscular 
activity.  Without  denying  the  possibility  of  a  formation  of  lactic  acid 
from  proteid,  he  states  tliat  with  lack  of  oxygen  we  have  to  deal  witli  an 
incomplete  combustion  of  the  lactic  acid  derived  by  a  cleavage  of  the  sugar. 
Hoppe-Seyler '^  also  positively  defends  the  view  as  to  the  formation  of 
lactic  acid  from  carbohydrates.  He  is  of  the  view  that  lactic  acid  is 
produced  from  the  carbohydrates  by  the  cleavage  of  the  sugar  only  with 
lack  of  oxygen,  while  with  suflBcient  oxygen  the  sugar  is  burned  into 
carbon  dioxide  and  water.  The  formation  of  lactic  acid  in  the  absence  of 
free  oxygen  and  in  the  presence  of  glycogen  or  dextrose  is,  according  to 
Hoppe-Seyler,  very  probably  a  function  of  all  living  protoplasm.  We 
have  good  ground  for  the  assumption  of  the  formation  of  lactic  acid 
from  proteid  as  well  as  from  carbohydrates.  Phosphocarnic  acid  is  consid- 
ered by  Siegfried  as  another  source  of  sarcolactic  acid. 

The  lactic  acids  are  amorphous.  They  have  the  appearance  of  colorless 
or  faintly  yellowish,  acid-reacting  syrups  which  mix  in  all  proportions  with 
water,  iilcohol,  or  ether.  The  salts  are  soluble  in  water,  and  most  of  them 
also  in  alcohol.  The  two  acids  are  differentiated  from  each  other  by 
their  different  optical  properties — paralactic  acid  being  dextrogyrate, 
Avhile  fermentation  lactic  acid  is  optically  inactive — also  by  their  different 
solubilities  and  the  different  amounts  of  water  of  crystallization  of  the 
calcium  and  zinc  salts.  The  zinc  salt  of  fermentation  lactic  acid  dissolves 
in  58-63  parts  of  water  at  14-15°  C.  and  contains  18.18^  water  of  crystalli- 
zation, corresponding  to  the  formula  Zn(C3H^03),  +  3H,0.  The  zinc  salt 
of  paralactic  acid  dissolves  in  17.5  parts  of  water  at  the  above  tempera- 
ture and  contains  ordinarily  12.9^  water,  corresponding  to  the  formula 
Zn(C3H^03),  +  2H2O.  The  calcium  salt  of  fermentation  lactic  acid  dis- 
solves in  9.5  parts  water  and  contains  29.22^  {=  5  mol.)  water  of  crystalli- 
zation, while  calcium  paralactate  dissolves  in  12.4  parts  water  and  contains 
24.83  or  26.21^  {=^  or  4^  mol.)  water  of  crystallization.  Both  calcium 
salts  crystallize,  not  unlike  tyrosin,  in  spheres  or  tufts  of  very  fine  micro- 
scopic needles.  Hoppe-Seyler  and  Araki,'  who  have  closely  studied  the 
optical  properties  of  the  lactic  acids  and  lactates,  consider  the  lithium  salt 
as  best  suited  for  the  preparation  and  quantitative  estimation  of  the  lactic 
acids.     The  lithium  salt  contains  7.29^  Li. 


>  Journ.  f.  prakt.  Cbem.  (N.  F.),  Bd.  21. 

'  Vircliow'3  Festsclirift,  also  Ber.  d.  deutscli.  cbem.  Gesellscb.,  Bd.  25,  Referatb., 
S.  685. 

»  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  20. 


LACTIC  ACIDS.  345 

Lactic  acids  may  be  detected  in  organs  and  tissues  in  the  following 
manner:  After  complete  extraction  with  water,  the  proteid  is  removed 
by  coagulation  at  boiling  temperature  and  the  addition  of  a  small  quantity 
of  sul])huric  acid.  The  liquid  is  then  exactly  neutralized  while  boiling  with 
caustic  baryta,  and  then  evai)oratcd  to  a  syrup  after  filtration.  The  residue 
is  precipitated  ..with  absolute  alcohol,  and  the  proci])itate  completely  ex- 
tracted with  alcohol.  The  alcohol  is  entirely  distilled  from  the  united  alco- 
holic extracts,  and  the  neutral  residue  is  shaken  with  ether  to  remove  the 
fat.  The  residue  is  dissolved  in  water  and  pbospboric  acid  added,  and  re- 
peatedly shaken  with  fresh  quantities  of  ether,  which  dissolves  the  lactic 
acid.  The  ether  is  now  distilled  from  the  several  ethereal  extracts,  the 
residue  dissolved  in  water,  and  this  solution  carefully  warmed  on  the  water- 
bath  to  remove  the  last  traces  of  ether  and  volatile  acids.  A  solution 
of  zinc  lactate  is  prepared  from  this  filtered  solution  by  boiling  with  zinc 
carbonate,  and  this  is  evaporated  until  crystallization  commences  and  then 
allowed  to  stand  over  sulphuric  acid.  An  analysis  of  the  salts  is  necessary 
in  careful  work.  According  to  Heffter  '  in  muscles  not  having  undergone 
rigor  mortis  the  lactic  acid  can  be  extracted  more  easily  by  alcohol  than 
by  water. 

Fat  is  never  absent  in  the  muscles.  Some  fat  is  always  found  in  the 
intermuscular  connective  tissue;  but  the  muscle-fibres  themselves  also  con- 
tain fat.  The  quantity  of  fat  in  the  real  muscle  substance  is  always  small, 
usually  amounting  to  about  10  p.  m.  or  somewhat  more.  A  considerable 
quantity  of  fat  in  the  muscle-fibres  is  only  found  in  fatty  degeneration. 
A  part  of  the  muscle-fat  can  be  readily  extracted,  while  another  part  can 
be  extracted  only  with  the  greatest  difficulty.  This  latter  part  is  claimed  to 
be  divided  in  the  contractile  substance  and  is  richer  in  free  fatty  acids, 
standing,  according  to  Zuntz  and  Bogdaxow,'  in  close  relationship  to  the 
activity  of  the  muscles  because  it  is  consumed  during  work.  Lecithm  is  a 
regular  constituent  of  the  muscles,  and  it  is  quite  possible  that  the  fat  which 
is  difficult  of  extraction  and  which  is  rich  in  fatty  acids  depends  in  part  on 
a  decomposition  of  the  lecithin. 

The  Mineral  Bodies  of  the  Muscles.  The  ash  remaining  after  burning 
the  muscle,  which  amounts  to  about  10-15  p.  m.,  calculated  on  the  moist 
muscle,  is  acid  in  reaction.  The  largest  constituents  are  potassium  and 
phosphoric  acid.  Next  in  amount  we  have  sodium  and  magnesium,  and 
lastly  calcium,  chlorine,  and  iron  oxide.  Sulphates  exist  only  as  traces  in 
the  muscles,  but  are  formed  by  the  burning  of  the  proteids  of  the  muscles, 
and  therefore  occur  in  abundant  quantities  in  the  ash.  The  muscles  con- 
tain such  a  large  quantity  of  potassium  and  phosphoric  acid  that  potassium 
phosphate  seems  to  be  unquestionably  the  predominating  salt.  Chlorine  is 
found  in  such  insignificant  quantities  that  it  is  perhaps  derived  from  a  con- 
tamination witli  blood  or  lymph.     The  quantity  of  magnesium  is,  as  a  rule, 

'  Arch.  f.  exp.  Path.  u.  Pharni.,  Bd.  38. 

'  Du  Bois-Reymoud's  Arch.,  1897.  See  also  the  references  to  the  literature  ou  the 
methods  for  the  quautitative  estimation  of  fat  iu  Chapter  IV,  page  97. 


346  MUSCLE. 

considerably  greater  than  that  of  calcium.  Iron  occurs  only  in  very  small 
amounts. 

The  gases  of  the  muscles  consist  of  large  quantities  of  carbon  dioxide, 
besides  traces  of  nitrogen. 

Rigor  Mortis  of  the  Muscles.  If  the  influence  of  the  circulating  oxy- 
genated blood  is  removed  from  the  muscles,  as  after  death  of  the  animal  or 
by  ligature  of  the  aorta  or  the  muscle-arteries  (Stenson's  test),  rigor 
mortis  sooner  or  later  takes  place.  The  ordinary  rigor  appearing  under 
these  circumstances  is  called  the  spontaneous  or  the  fermentive  rigor, 
because  it  seems  to  depend  in  part  on  the  action  of  an  enzyme.  A  muscle 
may  also  become  stiff  for  other  reasons.  The  muscles  may  become  momen- 
tarily stiff  by  warming,  in  the  case  of  frogs  to  40°,  in  mammalia  to  48-50°, 
and  in  birds  to  53°  C.  (heat-rigor).  Distilled  water  may  also  prod  nee  a 
rigor  in  the  muscles  (water-rigor).  Acids  even  when  very  weak,  snch  as 
carbon  dioxide,  may  quickly  produce  a  rigor  (acid-rigor),  or  hasten  its 
appearance.  A  number  of  chemically  different  substances,  such  as  chloro- 
form, ether,  alcohol,  ethereal  oils,  caffein,  and  many  alkaloids,  j)roduce  a 
similar  effect.  The  rigor  vv^hich  is  produced  by  means  of  acids  or  other 
agents  which,  like  alcohol,  coagulate  proteids  must  be  considered  as  pro- 
duced/by entirely  different  processes  from  those  causing  spontaneous  rigor. 

When  the  muscle  j)asses  into  rigor  mortis  it  becomes  shorter  and  thicker, 
harder  and  non-transparent,  less  ductile.  The  acid  part  of  the  amphoteric 
reaction  becomes  stronger,  which  is  explained  by  most  investigators  by  a 
formation  of  lactic  acid.  There  is  hardly  any  doubt  that  this  increase  in 
acidity  may  at  least  in  part  be  due  to  a  transformation  of  a  part  of  the 
diphosphate  into  monophosphate  by  the  lactic  acid.  The  statements  in 
regard  to  the  presence  or  absence  of  free  lactic  acid  in  the  rigor  mortis 
muscle  are  contradictory.^  Besides  the  formation  of  acid,  the  chemical 
processes  which  take  place  in  rigor  of 'the  muscles  are  the  following:  By 
the  coagulation  of  the  plasma  a  myosin-clot  is  produced  which  is  the  cause 
of  the  hardening  and  of  the  diminished  transparency  of  the  muscle,  but  this 
view  must  be  changed  on  account  of  the  researches  of  v.  Furth,  which 
have  shown  that  clot  consists  of  myogen  and  myosin-fibrin.  The  appear- 
ance of  this  clot  may  be  hastened  by  the  simultaneous  occurrence  of  lactic 
acid.  Carbon  dioxide  is  also  formed,  which  does  not  seem  to  be  a  direct 
oxidation  product,  but  a  product  of  the  cleavage  processes.  Hermann  ' 
claims  that  carbon  dioxide  is  produced  in  the  removed  muscle,  even  in  the 
absence  of  oxygen,  when  it  passes  into  rigor  mortis. 

'  It  is  iini)ossible  to  euter  into  details  of  the  disputed  stutements  as  to  the  reaction  of 
the  muscles,  etc.  We  will  only  refer  to  the  works  of  Rohmanu,  Pfliiger's  Arch.,  Bdd. 
50  and  55,  and  Hefter,  Arch.  f.  exp.  Path.  u.  Pliarm.,  Bdd.  31  and  38.  These  works 
contaiD  also  the  researches  of  the  older  investigators  more  or  less  completely. 

'  "  Untersuchungen  fiber  den  Stoffwechsel  der  Muskelu,"  etc.     Berlin,  1867. 


METABOLISM  IN  TUB  MUSCLES.  347 

As  many  investigators  admit  of  an  increased  formution  of  lactic  acid  on 
the  appearance  of  rigor  mortis,  the  question  arises,  from  what  constituents 
of  tlie  muscle  is  this  acid  derived  ?  The  most  probable  explanation  is  that 
the  lactic  acid  is  produced  from  the  glycogen,  as  certain  investigators,  such 
as  Nasse  and  Wertiier,  have  observed  a  decrease  in  the  quantity  of 
glycogen  in  rigor  of  the  muscle.  On  the  other  side,  l^rniM'  lias  observed 
cases  in  which  no  consumption  of  glycogen  took  place  in  rigor  of  the 
muscle,  and  he  has  also  found  that  the  quantity  of  lactic  acid  produced  is 
not  proportional  to  the  quantity  of  glycogen.  It  is  therefore  possible  that 
the  consumption  of  glycogen  and  the  formation  of  lactic  acid,  in  the  muscles 
are  two  processes  independent  of  each  other,  and,  as  above  stated  in  regard 
to  the  formation  of  paralactic  acid,  the  lactic  acid  of  the  muscle  may  be 
considered  as  a  decomposition  product  of  proteid.  The  origin  of  the  carb.Dn 
dioxide  is  also  not  to  be  sought  for  in  the  decomposition  of  the  glycogen  or 
dextrose.  Pi'i.uger  and  Stixtzing''  have  found  that  in  the  muscle  a  sub- 
stance occurs  which  evolves  large  quantities  of  carbon  dioxide  on  boiling 
with  water,  and  it  is  probably  this  substance  which  is  decomposed  with  the 
formation  of  carbon  dioxide  in  tetanus  as  well  as  in  rigor.  In  this  connec- 
tion we  call  attention  to  the  fact  that  phosphocarnic  acid  yields  lactic  acid 
as  well  as  carbon  dioxide  as  cleavage  products. 

After  the  muscles  have  been  rigid  for  some  time  they  relax  again  and 
the  muscles  become  softer.  This  is  in  part  produced  by  the  strong  acid 
dissolving  the  myosin-clot  and  in  part,  and  in  all  probability  mainly,  upon 
the  commencement  of  putrefaction. 

Metabolism  in  the  Inactive  and  Active  Muscles.  It  is  admitted  by  a 
number  of  prominent  investigators,  Pfluger  and  Colasanti,  Zuntz  and 
RoHRiG,'  and  others,  that  the  exchange  of  material  in  the  muscles  is  regu- 
lated by  the  nervous  system.  When  at  rest,  when  there  is  no  mechanical 
exertion,  we  have  a  condition  which  Zuntz  and  Rohrig  have  designated 
^^  chemical  tonus.''''  This  tonus  seems  to  be  a  reflex  tonus,  for  it  may  be 
reduced  by  discontinuing  the  connection  between  the  muscles  and  the 
central  organ  of  the  nervous  system  by  cutting  through  the  spinal  cord  or 
the  muscle-nerves,  or  by  paralyzing  the  same  by  means  of  cnrara  poison. 
Tbe  possibility  of  reducing  the  chemical  tonus  of  the  muscles  by  any  of  the 
above-mentioned  means,  but  especially  by  the  action  of  cnrara,  offers  an 
important  means  of  deciding  the  extent  and  kind  of  chemical  processes 
going  on  in  the  muscles  when  at  rest.  In  comparative  chemical  investiga- 
tion of  the  processes  in  the  active  and  the  inactive  muscles  several  methods 

'  Nasse,  Beitr.  z.  Physiol,  der  kontrakt.  Substanz,  Pflllger's  Avch.,  Bd.  2  ;  Werlher, 
ibid.,  Bd.  46  :  Boiim,  ibid.,  B'dd.  23  and  46. 

»  Ptlugcr's  Arcli..  Bd.  18. 

5  See  tbe  works  of  Ptiuger  and  bis  pupils  in  Pfliiger's  Arch.,  Bdd  4,  12,  14,  16,  and 
18;  Rohrig.  ibid.,  Bd.  4,  S.  57.     See  also  Zuntz,  ibid.,  Bd.  12,  S.  522. 


348  MUSCLE. 

of  procedure  have  been  adopted.  The  removed  homonymous,  active  and 
inactive  muscles  have  been  compared,  also  the  arterial  and  venous  muscle- 
blood  in  rest  and  activity,  and  lastly  the  total  exchange  of  material,  the 
receipts  and  expenditures  of  the  organism,  have  been  investigated  under 
these  two  conditions. 

By  investigations  according  to  these  several  methods  it  has  been  found 
that  the  active  muscle  takes  up  oxygen  from  the  blood  and  returns  to  ifc 
carbon  dioxide,  and  also  that  the  quantity  of  oxygen  taken  up  is  greater 
than  the  oxygen  contained  in  the  carbon  dioxide  eliminated  at  the  same 
time.  The  muscle,  therefore,  holds  in  some  form  of  combination  a  part  of 
the  oxygen  taken  up  while  at  rest.  During  activity  the  exchange  of 
material  in  the  muscle,  and  therewith  the  exchange  of  gas,  is  increased. 
The  animal  organism  takes  up  considerably  more  oxygen  in  activity  than 
when  at  rest,  and  eliminates  also  considerably  more  carbon  dioxide.  The 
quantity  of  oxygen  which  leaves  the  body  as  carbon  dioxide  during  activity 
is  considerably  larger  than  the  quantity  of  oxygen  taken  up  at  the  same 
time;  and  the  venous  muscle-blood  is  poorer  in  oxygen  and  richer  in  carbon 
dioxide  during  activity  than  during  rest.  The  exchange  of  gases  in  the 
muscles  during  activity  is  the  reverse  of  that  at  rest,  for  the  active  muscle 
gives  tip  a  quantity  of  carbon  dioxide  which  does  not  correspond  to  the 
quantity  of  oxygen  taken  up,  but  is  considerably  greater.  It  follows  from 
this  that  in  muscular  activity  not  only  does  oxidation  take  place,  but  also 
splitting  processes  occur.  This  follows  also  from  the  fact  that  removed 
blood-free  muscles  when  placed  in  an  atmosphere  devoid  of  oxygen  can 
labor  for  some  time  and  also  yield  carbon  dioxide  (Hermann  '). 

During  muscular  inactivity,  in  the  ordinary  sense,  a  consumption  of 
glycogen  takes  place.  This  is  inferred  from  the  observations  of  several 
investigators  that  the  quantity  of  glycogen  is  increased  and  its  corresponding 
consumption  reduced  in  those  muscles  whose  chemical  tonus  is  reduced 
either  by  cutting  through  the  nerve  or  for  other  reasons  (Bernard,  Chan- 
DELON,  Way,"  and  others).  In  activity  this  consumption  of  glycogen  is 
increased,  and  it  has  been  positively  proved  by  the  researches  of  several 
investigators  (Nasse,  Weiss,  Kulz,  Marcuse,  Manche,  Morat  and 
Dufour')  that  the  quantity  of  glycogen  in  the  muscles  in  activity  decreases 
quickly  and  freely.  As  shown  by  the  researches  of  Chauveau  and  Kauf- 
MANN,  QuiNQUAUD,  MoRAT  and  DuFOUR,  Cavazzani,  and  especially  those 

'  L.  c.  Ill  regard  to  gas  excliange  in  removed  muscles  see  also  J.  Tissot,  Arch,  de 
Physiol,  (o),  Tomes  6  and  7,  and  Compt.  rend.,  Tome  120. 

"^  Chandelon,  Plluger's  Arch.,  Bd.  13  ;  Way,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  34, 
■which  contains  also  tiie  perliiient  literature. 

3  Nasse,  PiUiger's  Arch.,  Bd.  2  ;  Weiss,  Wien.  Sitzungsber. ,  Bd.  64  ;  Klilz,  in  Lud- 
wig's  Festschrift,  ]\Iarburg,  1891  ;  Marcu.se,  PtUiger's  Arch.,  Bd.  39;  Manche,  Zeitschr. 
f.  Biologic,  Bd.  25  ;  Morat  and  Dufour,  Arch.  f.  Physiol.  (5),  Tome  4. 


METABOLISM  IN  THE  MUSCLES.  349 

of  Seegen,'  the  sugar  is  removed  from  tlie  blood  and  consumed  during 
activity.  According  to  Seegen  a  very  abundant  formation  of  sugar  takes 
place  in  the  lis'er,  and  correspondingly  the  blood  of  the  liepatic  vein  is  much 
richer  in  sugar  than  that  in  the  portal  vein,  and  this  sugar  of  the  blood  is, 
according  to  him,  the  source  of  heat  formatiom  and  mechanical  activity. 
It  is  nevertheless  true  that  important  objections  have  been  presented 
against  a  few  of  these  investigations,  and  a  sugar  formation  according  to 
Seegen's  idea  has  been  denied  by  several  investigators,  and  recently  by 
ZuNTZ  and  JIosse;'  but  still  there  can  exist  hardly  any  doubt  that  sugar 
is  consumed  in  muscular  activity. 

The  amphoteric  reaction  of  the  iT^active  muscles  is  changed  during 
activity  to  an  acid  reaction  (Di'  Bois-Reymond  and  others),  and  the  acid 
reaction  increases  to  a  certain  point  with  the  work.  The  quickly  contract- 
ing pale  muscles  produce,  according  to  Gleiss,'  more  acid  during  activity 
than  the  more  slowly  contracting  red  muscles.  The  acid  reaction  appearing 
during  activity  was  formerly  considered  due  to  the  formation  of  lactic  acid, 
a  view  Avhich  has  been  contradicted  by  Astaschewsky,  Pfluger  and 
Warrex,*  who  found  less  lactic  acid  in  the  tetanized  muscle  than  when  at 
rest.  MoxARi  also  found  a  decrease  in  the  quantity  of  lactic  acid  during 
activity,  and  according  to  Hefter  the  quantity  of  lactic  acid  in  the  muscle 
is  diminished  in  tetanus  produced  by  poison.  Contrary  to  these  investiga- 
tions Marcuse  and  Werther  °  have  been  able  to  prove  the  formation  of 
lactic  acid  during  activity;  still  the  statements  are  very  contradictory. 
Other  observations  speak  for  a  formation  of  lactic  acid  during  activity. 
Thus  Spiro  found  an  increase  in  the  quantity  of  lactic  acid  in  the  blood 
during  work.  Colasanti  and  Moscatelli  found  small  quantities  of  lactic 
acid  in  human  urine  after  strenuous  marches,  and  Werther  observed 
abundance  of  lactic  acid  in  the  urine  of  frogs  after  tetanization.  According 
to  Hoppe-Setler,  on  the  contrary,  in  agreement  with  his  view  in  regard 
to  the  formation  of  lactic  acid,  a  formation  of  lactic  acid  does  not  take  place 
regularly  during  work,  but  only  when  insufficient  oxygen  is  supplied. 
ZiLLESEN '  has  also  found  that  on  artificially  cutting  off  the  oxygen  from 

'  Cbauveau  and  Kaufmann,  Compt.  rend.,  Tomes  103.  104.  and  105  ;  Quitiquaud, 
Maly's  Jahiesber.,  Bd.  16,  S.  321  ;  Morat  and  Dufour,  1.  c;  Cavazzaui,  Centralbl.  f. 
Physiol.,  Bd.  8 ;  Seegen,  "  Die  Zuckerbilduug  im  Tliierkorper,"  Berlin,  1890,  Centralbl. 
f.  Physiol.,  Bd.  8,  S.  417,  and  Bdd.  9  and  10 ;  Du  Bois-Reymond's  Arch.,  1895 and  1896: 
Pfliiger's  Arch.,  Bd.  50. 

'  Mosse,  Pflliger's  Arch.,  Bd.  63  ;  Zuntz,  Centralbl.  f.  Physiol..  Bd.  10,  and  Du  Bois- 
Reymond's  Arch..  1896.  S.  538.     See  also  Scheuck,  Pflliger's  Arch.,  Bdd.  61  and  65. 

3  Pflliger's  Arch.,  Bd.  41. 

*  Astaschewsky,  Zeitschr.  f.  physiol.  Chem.,  Bd.  4  ;  Warren.  Pflliger's  Arch.,  Bd.  24. 
'  Monari.  Maly's  Jahresber.,  Bd.  19,  S.  303  :  Hefter,  Arch.  f.  exp.  Path.  u.  Pharm., 

Bd.  31  ;  Mnrcuse,  1.  c. :  "Werther,  Pflliger's  Arch  ,  Bd.  46. 

*  Spiro,  Zeitschr.  f.  physiol.  Chem.,  Bd.  1  ;  Colasanti  and  Moscatelli,  Maly's  Jahres- 


350  MUSCLE. 

the  muscles  during  life  more  lactic  acid  was  formed  than  under  normal 
conditions. 

It  is  evident  that  the  experiments  with  the  muscles  in  situ — iu  other 
words,  with  muscles  through  which  blood  is  passing — cannot  yield  any  con- 
clusion to  the  above  question,  as  the  lactic  acid  formed  during  work  may 
perliaps  be  removed  by  the  blood.  The  following  objections  can  be  made 
against  those  experiments  in  which  lactic  acid  has  been  found  after  moderate 
work  in  the  blood  or  the  urine,  as  also  especially  against  the  experiments 
with  removed  active  muscles,  namely,  that  in  these  cases  the  supply  of 
oxvgen  to  the  muscles  was  not  sufficient,  and  that  the  lactic  acid  formed 
thereby  is  not,  in  accordance  with  the  views  of  Hoppe-Setler,  a  perfectly 
normal  process.  The  question  as  to  the  formation  of  lactic  acid  in  the 
active  muscle  under  perfect  physiological  conditions  is  still  an  open  one. 

According  to  Weyl  and  Zeitler,'  the  active  muscle  contains  more 
phosphoric  acid  (in  part  formed  by  the  decomposition  of  lecithin)  than  the 
inactive  muscle.  As  in  the  dead  muscle,  so  in  the  active  muscle,  the  some- 
what stronger  acid  reaction  is  in  part  due  to  a  greater  quantity  of  mono- 
phosphate. 

The  amount  of  proteids  in  the  removed  muscles  is,  according  to  the 
older  investigators,  decreased  by  work.  The  correctness  of  this  statement 
is,  however,  disputed  by  other  investigators.  The  older  statements  in  regard 
to  the  nitrogenous  extractive  bodies  of  the  muscle  iu  rest  and  in  activity 
are  likewise  uncertain.  According  to  the  recent  researches  of  Monari  ^  the 
total  quantity  of  creatin  and  creatinin  is  increased  by  work,  and  indeed  the 
amount  of  creatinin  is  especially  augriiented  by  an  excess  of  muscular 
activity.  The  creatinin  is  formed  essentially  from  the  creatin.  In  excessive 
activity  Moxari  also  found  xantho-creatinin  in  the  muscle,  and  the  quan- 
tity was  one  tenth  of  that  of  the  creatinin.  The  quantity  of  xanthin  bodies 
is,  according  to  Monari,  decreased  under  the  influence  of  work.  It  seems 
to  have  been  positively  shown  that  the  active  muscle  contains  a  smaller 
quantity  of  bodies  soluble  in  water  and  a  larger  quantity  of  bodies  soluble 
in  alcohol  than  the  resting  muscle  (Helmholtz  '). 

Attempts  liave  been  made  to  solve  the  question  relative  to  the  behavior 
of  the  nitrogenized  constituents  of  the  muscle  at  rest  and  during  activity  by 
determining  the  total  quantity  of  nitrogen  eliminated  under  these  different 
conditions  of  the  body.  While  formerly  it  was  held  with  Liebig  that  the 
elimination  of  nitrogen  by  the  urine  was  increased  by  muscular  work,  the 
researches  of  several  experimenters,  especially  those  of  Voit  on  dogs  and 


ber.,  Bd.  17,  S.  212  ;  Hoppe-Seyler,  1.  c,  and  Zeitschr.  f.   physiol.  Chem.,  Bd.  19,   S. 
476;  Zillesen,  ibid.,  Bd.  15. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  10,  S.  557. 

'  M:ily's  Jahresber.,  Bd.  19,  8.  296. 

8  Arch.  f.  Aiiat.  u.  Physiol.,  1845. 


METABOLISM  IN  THE  MUSCLES.  Sf)! 

Pettenkofku  and  \'oit  '  on  men,  have  led  to  quite  dilterent  results.  Tiiey 
have  shown,  as  has  also  lately  been  confirmed  by  other  investigators, 
especially  1.  !Munk  and  IIiusfiii-Ei-u,''  that  during  work  no  increase  or  only 
a  very  insignificant  increase  in  the  elimination  of  nitrogen  takes  place. 

We  should  not  omit  to  mention  the  fact  that  a  series  of  experiments 
have  been  made  sliowing  a  significant  increase  in  the  metabolism  of  jjroteids 
during  or  after  work.  We  have  as  example  the  observations  of  Flint  and 
Pavy  on  a  pedestrian,  v.  Wolff,  v.  Funke,  Kreuziiage  and  Kellner 
on  a  horse,  and  Dinloi'  and  his  collaborators"  on  working  human  beings 
and  others.  The  researches  on  the  elimination  of  sulphur  during  rest  and 
activity  also  belong  to  this  category.  The  elimination  of  nitrogen  and 
sulphur  runs  parallel  with  the  metabolism  of  proteids  in  resting  and  active 
persons,*  and  the  quantity  of  sulphur  excreted  by  the  urine  is  therefore  also 
a  measure  of  the  proteid  decomposition.  The  older  researches  of  Engel- 
MANN,'  Flint,  and  Pavy,  as  well  as  the  more  recent  ones  of  Beck  and 
Benedikt,'  and  Dunlop  and  his  collaborators,  show  an  increased  elimina- 
tion of  sulphur  during  or  after  work,  and  this  speaks  for  an  increased  pro- 
teid metabolism  because  of  muscular  activity. 

On  one  side  an  increased  proteid  metabolism  has  been  observed  on 
account  of  work,  and  on  the  other  side  no  increased  proteid  metabolism  is 
observed  on  excessive  activity.  These  contradictory  observations  are  not 
directly  in  opposition  to  each  other,  because,  as  will  be  shown  later  (Chapter 
XVIII),  the  extent  of  proteid  metabolism  is  dependent  upon  several  condi- 
tions, such  as  the  quantity  and  composition  of  the  food,  the  condition  of  the 
adipose  tissue,  the  action  of  work  on  the  respiratory  mecha,nism,  etc.,  etc., 
all  of  which  might  have  an  influence  on  the  result  of  the  experiments.  In 
the  present  state  of  this  (luestion  we  can  probably  maintain  that  an  increased 
proteid  metabolism  is  not  necessarily  directly  caused  by  work,  but  that  it 
occurs  in  those  bodies  where  the  store  of  non-nitrogenous  foods  present 
or  supplied  with  the  food  is  insufficient,  as  also  when  the  dyspnotic  symptoms 
accompanied  by  an  increased  destruction  of  proteid  appear  with  increased 
activity.^ 

'  Untersucliungen  liber  den  Einfluss  des  Koclisalzes,  des  KafiFees  und  der  Muskelbe- 
wegungen  aiif  den  Stoffweclisel  (Munclicii,  18(!0).  and  Zeitschr.  f.  Biologic,  Bd.  2. 

'  I.  Munk,  Du  Bois-Reyniond's  Arch.,  1890  and  189G  ;  Hirschfeid,  Virchow's  Arch., 
Bd.  121. 

3  Flint,  Journ.  of  Anat.  and  Physiol..  Vols.  11  and  12  ;  Pavy,  The  Lancet,  1876  and 
1877;  Wolff,  V.  Funke.  Kellner,  cited  from  Voit.  Hermann's  Handb.,  Bd.  6,  S.  197; 
Dunlop,  Noel-Paton,  Stockman,  and  Maccadam,  Journ.  of  Physiol.,  Vol.  22. 

*  See  I.  Munk,  Du  Bois-Reyniond's  Arch.,  1895. 
=  Du  Bois-Riymond's  Arch.,  1871. 

*  Flint,  1.  c;  Pavy,  1.  c. ;  Beck  and  Benedikt,  Pflilger's  Arch.,  Bd.  54. 

'  See  Kummacher,  Zeitschr.  f.  Biologie,  Bd.  33,  and  the  works  of  I.  Munk  in  Du 
Bois-Reymond's  Arch.,  1890  and  1896. 


352  MUSCLE. 

The  older  investigations  on  tlie  amount  of  fat  in  removed  mascles  during 
activity  and  at  rest  have  not  led  to  any  definite  results.  According  to  the 
recent  investigations  of  Zuntz  and  Bogdanow  '  the  fat  belonging  to  the 
muscle-fibres  and  which  is  difficultly  extracted  takes  part  in  work.  Besides 
these  we  have  several  researches  by  Voit,  Pettenkofer  and  Voit, 
J.  Frentzel/  and  others  which  make  aa  increased  destruction  of  fat  during 
work  probable.  We  must  also  mention  the  statement  of  Siegfried  '  that 
the  quantity  of  phosphocarnic  acid  is  decreased  during  work. 

If  the  results  of  the  investigations  thus  far  made  of  the  chemical 
processes  going  on  in  the  active  and  inactive  muscle  were  collected  together, 
we  would  find  the  following  characteristics  for  the  active  muscle.  The 
active  muscle  takes  up  more  oxygen  and  gives  off  more  carbon  dioxide  than 
the  inactive  muscle;  still  the  elimination  of  carbon  dioxide  is  increased 
considerably  more  than  the  absorption  of  oxygen.     The  respiratory  quotient, 

CO 

—7^-)  is  found  to  be  regularly  raised  during  work;  yet  this  rise,  which  will 

be  explained  in  detail  in  a  following  chapter  on  metabolism,  can  hardly  be 
conditioued  on  the  kind  of  processes  going  on  in  the  muscle  during  activity 
with  a  sufficient  supply  of  oxygen.  In  work  a  consumption  of  carbohydrates, 
glycogen,  and  sugar  takes  place.  A  consumption  of  sugar  seems  only  to 
have  Ijeen  shown  in  muscle  with  blood  circulation,  while  a  consumption  of 
glycogen  also  has  been  observed  in  removed  muscle.  The  acid  reaction  of 
the  muscle  becomes  greater  with  work.  In  regard  to  the  extent  of  a 
re-formation  of  lactic  acid  opinion  is  divided.  An  increased  consumption 
of  fat  has  occasionally  been  observed.  The  quantity  of  phosphocarnic  acid 
decreases,  and  an  increase  in  the  nitrogenous  extractives  of  the  creatinin 
group  seems  also  to  occur.  Proteid  metabolism  has  been  found  increased 
in  certain  series  of  experiments,  and  not  in  others;  but  an  increased  elimina- 
tion of  nitrogen  as  a  direct  consequence  of  muscular  exertion  has  thus  far 
not  been  positively  proved. 

In  close  connection  with  the  above-mentioned  facts  we  have  the  question 
as  to  the  origin  of  muscular  activity  so  far  as  it  has  its  origin  in  chemical 
processes.  In  the  joast  the  generally  accepted  opinion  was  that  of  Liebig, 
that  the  source  of  muscular  action  consisted  of  a  metabolism  of  the  joroteid 
bodies;  to-day  another,  generally  accepted,  view  prevails.  Pick  and  Wis- 
LICENUS  *  climbed  the  Faulhorn  and  calculated  the  amount  of  mechanical 
force  expended  in  the  attempt.  With  this  they  compared  the  mechanical 
equivalent  transformed  in  the  same  time  from  the  proteids,  calculated  from 

'  See  foot-note  2,  page  345. 
«  Pfliiger's  Arch.,  Bd.  68. 
»  Zeilschr.  f.  pbysiol.  Chem.,  Bd.  21. 

*  Vierteljahrsscbr.  d.  Zurich,  naturf.  Gesellsch.,  Bd.  10.     Cited  from  Centralbl.  f.  d. 
med.  Wiss.,  1866,  S.  309. 


METAIiOLISM  IN  THE  MUSCLES.  353 

the  nitrogen  eliminated  with  the  urine,  and  found  that  the  work  really 
performed  was  not  by  any  means  compensated  by  the  consumption  of 
proteid.  It  was  therefore  i)roved  by  tliis  that  proteids  alone  cannot  be  the 
source  of  muscuhir  activity,  and  tliat  this  depends  in  great  measure  on  the 
metabolism  of  non-nitrogenous  substances.  Many  other  observations  have 
led  to  the  sanieresult,  especially  the  experiments  of  A'oit,  of  Pettexkofer 
and  VoiT,  and  of  other  investigators,  whose  experiments  show  that  while 
the  elimination  of  nitrogen  remains  nnchanged,  the  elimination  of  carbon 
dioxide  during  work  is  very  considera])ly  increased.  It  is  also  generally 
considered  as  positively  proved  that  muscular  work  is  produced,  at  least  in 
greatest  part,  by  the  metabolism  of  non-nitrogenous  substances.  Neverthe- 
less there  is  no  warrant  for  the  statement  that  muscular  activity  is  pro- 
duced entirely  at  the  cost  of  the  non-nitrogenous  substances,  and  that  the 
proteid  bodies  are  without  importance  as  a  source  of  force. 

The  recent  investigations  of  Pfluger'  are  of  great  interest  in  this  con- 
nection, lie  fed  a  bulklog  for  more  than  7  months  with  meat  which  alone 
did  not  contain  sufficient  fat  and  carbohydrates  for  the  production  of  heart 
activity,  and  then  let  him  work  very  hard  for  periods  of  1-i,  35,  and  41 
days.  The  positive  results  obtained  by  these  series  of  experiments  was  that 
^'  complete  muscular  activity  may  be  effected  to  the  greatest  extent  in  the 
absence  of  fat  and  carbohydrates,"  and  the  ability  of  proteids  to  serve  as  a 
source  of  muscular  energy  cannot  be  denied. 

The  nitrogenous  as  well  as  the  non-nitrogenous  nutriments  may  serve  as 
source  of  force;  but  the  views  are  divided  in  regard  to  the  relative  value  of 
these.  Pflugek  claims  that  no  muscular  work  takes  place  without  a 
decomposition  of  proteid,  and  the  living  cell-substance  prefers  always  the 
proteid  and  rejects  the  fat  and  sugar,  contenting  itself  with  these  only  when 
proteids  are  absent.  Other  investigators,  on  the  contrary,  believe  that  the 
muscles  first  draw  on  the  supply  of  non-nitrogenous  nutriments,  and  accord- 
ing to  Seegen,  Chauveau,  and  Laulanie''  the  sugar  is  indeed  the  only 
direct  source  of  muscular  force.  The  last-mentioned  investigator  holds 
that  the  fat  is  not  directly  utilized  for  work,  but  only  after  a  previous 
conversion  into  sugar.  Zuntz  and  his  collaborators '  have  made  strong 
objections  against  the  correctness  of  such  a  view.  If,  according  to  ZrxTZ, 
the  fat  must  be  first  transformed  into  sugar  before  it  can  serve  as  source  of 
muscular  work,  it  must  require  about  30,<  more  energy  to  perform  the  same 
work  with  fatty  food  as  it  does  Avith  carbohydrates;  but  this  is  not  the  case. 

'  Ptluger'3  Arch.,  Bd.  50. 

'  See  Seegen,  foot-note  1.  page  349.  The  works  of  Cliauveau  and  his  collaborators 
are  found  in  Couip.  rend.,  Tomes  121,  122,  and  123  ;  Lauhinie,  Arch,  de  Physiol.  (5), 
Tome  8. 

3  See  Zuntz,  Du  Bois-Reyraond's  Arch.,  1896,  S.  358  and  S.  538  ;  Zuntz  and  Heyne- 
man,  ibid.,  1897.  S.  535. 


354  MUSCLE. 

According  to  his  investigations  all  foods  have   the  same  ability  to  yield 

material   for   muscular  work,  -without   being  previously  transformed  into 

sugar.     It  is  apparent  that  such  an  assumption  does  not  stand  in  opposition 

to  the  view  suggested  by  Bukge,  Zuntz,  I.  Mdnk,  and  others,  iu  which 

the  non-nitrogenous  bodies  are  those  which  are  prominently  necessary  in  the 

defrayal  of  work  in  the  muscles. 

SiEGFUiED  considers,  as  above  stated,  the  phosphocarnic  acid  as  a  source  of  force. 
According  to  bis  and  Kruger'b  '  researches  pbospliocarnic  acid  occurs  in  part  ready  in 
tbe  muscle,  which  yields  ou  cleavage,  among  other  bodies,  carbon  dioxide,  and  in  part 
a  bypothelical  aldehyde  combination  of  the  same — a  combination  which  forms  phospho- 
carnic acid  on  oxidation.  Seigfrted  therefore  makes  the  suggestion  that  in  the  resting 
muscle,  which  requires  more  oxygen  than  in  tbe  carl)on  dioxide  eliminated,  this  reduc- 
ing aldehyde  substance  is  gradually  oxidized  to  phosphocarnic  acid,  which  is  used  in  the 
activity  of  the  muscle  with  the  splitting  off  of  carbon  dioxide. 

Quantitative  Composition  of  the  Muscle.  A  large  number  of  anah'ses 
have  been  made  of  the  flesh  of  various  animals  for  purely  practical  purposes, 
in  order  to  determine  the  nutritive  value  of  different  varieties  of  meat;  but 
we  have  no  exact  scientific  analyses  with  sufficient  regard  to  the  quantity  of 
different  albuminous  bodies  and  the  remaining  muscle-constituents,  or  these 
analyses  are  incomplete  or  of  little  value. 

To  give  the  reader  some  idea  of  the  variable  composition  of  muscle- 
substance  we  give  the  following  summary,  chiefly  obtained  from  K.  B. 
HoFMAN"]sr's*  book.     The  figures  are  parts  per  1000. 

Muscles  of 
Muscles  of  Muscles  of  Cold-blooded 

Mammals.  Birds.  Animals. 

Solids 217-255  227-283                        200 

Water 745-783  717-773                        800 

Organic  bodies 208-245  217-263  180-190 

Inorganic  bodies 9-10  10-19  10-20 

Myosin 35-106  29.8-111  29.7-87 

Stroma  substance  (Danilewsky) 78-161  88.0-184  70.0-121 

Alkali  albuminate 29-80  —                             — 

Crealin 2  3.4                           2.3 

Xanthin  bodies 0.4-0.7  0.7-0.3                       — 

Inosinic  acid  (barium  salt) 0.1  0.1-0.3                       — 

Protic  acid —  —                           7.0 

Taurin 0.7(horse)  —                           1.1 

Inosit  0.03  —                           — 

Glycogen 4-5  —                           3-5 

Lactic  acid 0.4-0.7  —                          — 

Phosphoric  acid 3.4-4.8 

Potash 3.0-4.0 

Soda 0.4 

Lime 0.2 

Magnesia 0.4 

Sodium  chloride 0.04-0.1 

Iron  oxide 0.03-0.1 

In  this  table,  which  has  little  value  because  of  the  variation  in  the  com- 
position of  the  muscles,  we  have  no  results  as  to    tlie  estimates  of   fat. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  22. 

»  Lehrbuch  d.  Zoochem.  (AVien,  1876),  S.  104. 


COMPOSITION   OF   THE  MUSCLES.  '.1^)5 

Owing  to  tlie  variable  f|nantity  of  fat  in  meat  it  is  hardly  possible  to  quote 
a  positive  average  for  this  body.  After  most  careful  elTorts  to  remove  the 
fat  from  the  muscles  without  chemical  means,  it  has  been  found  that  a 
variable  quantity  of  intermuscular  fat,  which  does  not  really  belong  to  the 
muscular  tissue,  always  remains.  The  smallest  quantity  of  fat  in  the 
muscles  from  lean  oxen  is  G.l  p.  m.  according  to  Grouven,  and  7.G  ]>.  m. 
according  to  Pktkrsen.  This  last  observer  also  found  regularly  a  smaller 
quantity  of  fat,  7.6-8.G  p.  m.,  in  the  fore  quarter  of  oxen,  and  ;i  greater 
amount,  30.1-34.6  p.  m.,  in  the  hind  quarter  of  the  animal,  but  this  could 
not  be  substantiated  by  Stkii,,'  A  small  quantity  of  fat  has  also  been  fourjd 
in  the  muscles  of  wild  animals,  li.  Kr)Nio  and  Fakwick  found  10.7  p.  m. 
fat  in  the  muscles  of  the  extremities  of  the  hare,  and  14.3  p.  m.  in  tlie 
muscles  of  the  partridge.  The  muscles  of  pigs  and  fattened  animals  are, 
Avlien  all  the  adherent  fat  is  removed,  very  rich  in  fat,  amounting  to  40-00 
p.  m.  The  muscles  of  certain  fishes  also  contain  a  large  quantity  of  fat. 
According  to  Almex,  in  the  flesh  of  the  salmon,  the  mackerel,  and  the  eel 
there  are  contained  respectively  100,  104,  and  320  p.  m.  fat." 

The  quantity  of  water  in  the  muscle  is  liable  to  considerable  variation. 
The  (juantity  of  fat  has  a  special  influence  on  the  quantity  of  water,  and  we 
find,  as  a  rule,  that  the  flesh  which  is  deficient  in  water  is  corresjjondingly 
rich  in  fat.  The  quantity  of  water  does  not  depend  alone  upon  the  amount 
of  fat,  but  upon  many  other  circumstances,  among  which  we  must  mention 
the  age  of  the  animal.  In  young  animals  the  organs  in  general,  and  there- 
fore also  the  muscles,  are  poorer  in  solids  and  richer  in  water.  In  man  the 
quantity  of  water  decreases  until  mature  age,  but  increases  again  towards  old 
age.  Work  and  rest  also  infinence  the  quantity  of  water,  for  the  active 
muscle  contains  more  water  than  the  inactive.  The  uninterruptedly  active 
heart  should  therefore  be  the  muscle  richest  in  water.  That  the  quantity 
of  water  may  vary  independently  of  the  amount  of  fat  is  strikingly  shown 
by  comparing  the  muscles  of  different  species  of  animals.  In  cold-blooded 
animals  the  muscles  generally  have  a  greater  (juantity  of  water,  in  birds  a 
lower.  The  comparison  of  the  flesh  of  cattle  and  fish  shows  very  strikingly 
the  different  amounts  of  water  (independent  of  the  quantity  of  fat)  in  the 
flesh  of  different  animals.  According  to  the  analysis  of  Almex,'  the 
muscles  of  lean  oxen  contain  15  p.  m.  fat  and  767  p.  m.  water;  the  flesh  of 
the  pike  contains  only  1.5  fat  and  839  p.  m.  water. 

For  certain  purposes,  as,  for  example,  in  experiments  on  metabolism,  it 

'  Ptlliger's  Arcli.,  Bd.  61. 

'  In  regard  to  the  literiUure  and  complete  statements  on  the  composition  of  flesh  of 
various  iiuimals,  see  Konig,  Chemie  der  menscblicben  Nahrungs-  iiud  Genussmittel, 
3.  Aufl. 

'  Nova  Act.  rog.  Soc.  Scient.  Upsal.,  Vol.  extr.  ord.,  1877;  also  Maly's  .Tahresber., 
Bd.  7,  S.  307. 


356  MUSCLE. 

is  important  to  know  the  elementary  composition  of  flesh.  In  regard  to 
the  quantity  of  nitrogen  we  generally  accept  Voit's  figare,  namely,  3.4^, 
as  an  average  for  fresh  lean  meat.  According  to  ISTowak  and  Huppeet  ' 
this  quantity  may  vary  about  0.6^,  and  in  more  exact  investigations  it  is 
therefore  necessary  to  specially  determine  the  nitrogen.  Complete  elemen- 
tary analyses  of  flesh  have  recently  been  made  with  great  care  by  Argu- 
iiNSKT.  The  average  for  ox-flesh  dried  in  vacuo  and  free  from  fat  and 
with  the  glycogen  deducted  was  as  follows:  C  49.6;  H  6.9;  N  15.3; 
O  -j-  S  23.0;  and  ash  5.2^.  The  relationship  of  the  carbon  to  nitrogen, 
which  Argutinsky  calls  the  "  flesh  quotient,"  is  on  an  average  3.24  : 1. 
According  to  Salkowski,^  of  the  total  nitrogen  of  beef  77.4,^  was  insoluble 
proteids,  10.08^^  soluble  proteids,  and  12.52^  other  soluble  bodies. 

We  have  complete  investigations  by  Katz  '  as  to  the  quantity  of  mineral 
constituents  of  the  mascles  from  man  and  animals.  The  variation  in  the 
different  elements  is  considerable.  Pork  is  much  richer  in  sodium  as  com- 
pared with  potassium  than  other  kinds  of  meat.  The  quantity  of  mag- 
nesium is  greater  and  often  considerably  greater  than  calcium  in  all  kinds  of 
flesh  investigated,  with  the  exception  of  shell-fish,  the  eel  and  the  pike.  Beef 
is  very  poor  in  calcium.  Potassium  and  phosphoric  acid  are  the  most 
abunjaant  mineral  constituents  of  all  flesh. 

Non-striated  Muscles. 

The  smooth  muscles  have  a  neutral  or  alkaline  reaction  (Du  Bois- 
Eeymond)  when  at  rest.  During  activity  they  are  acid,  which  is  inferred 
from  the  observations  of  Beriststeii^,  who  found  that  the  nearly  continually 
contracting  sphincter  muscle  of  the  Anodooita  is,  acid  during  life.  The 
smooth  muscles  may  also,  according  to  Heidenhaiit  and  Kuhne,  pass  into 
rigo7'  mortis  and  thereby  become  acid.  A  spontaneously  coagulating  plasma 
has  not  thus  far  been  obtained,  but  it  may  be  considered  as  the  juice 
obtained  by  pressing  the  muscles  of  the  Anodonta  and  which  coagulates 
immediately  at  +  45°  C.  or  within  24  hours  at  the  ordinary  temperature. 
Myosin  has  not  been  found  in  the  smooth  muscles.  Heidenhain  and 
Hellwig  '  have  obtained  from  the  smooth  muscles  of  a  dog  an  albuminous 
body  which  coagulates  at  -f  45°  to  49°  C.  and  which  is  analogous  to 
musculin.  The  smooth  muscles  contain  large  amounts  of  alkali  albuminates 
besides  an  albumin  coagulating  at  -|-  75°  C. 

'  Voit,  Zeitschr.  f.  Biologie,  Bd.  1  ;  Iluppert,  lUd.,  Bd.  7  ;  Nowak,  Wien.  Sitzungs- 
ber.,  Bd.  64,  Abth.  2. 

'  Argutiiisky,  Pfluger's  Arch.,  Bd.  55  ;  Salkowski,  Ceutialbl.  f.  d.  ined.  Wissenscb., 
1894. 

'Pfluger's  Arch.,  Bd.  63. 

*Du  Bois-Reymond  in  Nasse,  Hermann's  Handb.,  Bd.  1,  S.  339;  Bernstein,  ibid.; 
Heidenbain,  Md.,  S.  340,  "witb  ITellwig,  ibid.,  S.  339  ;  KUhne,  Lehrbucb,  S.  331. 


NON-STRIATED  MUSCLES.  357 

In  recent  times  our  knowledge  of  the  j^roteids  of  the  smooth  muscles  lias 
been  advanced  by  the  researches  of  Velichi.'  He  has  prepared  a  neutral 
plasma  from  the  gizzard  of  geese,  according  to  v.  FuuTii's  method.  1'his 
plasma  coagulated  spontaneously  at  the  temperature  of  the  room,  although 
slowly.  It  contained  a  globulin,  precipitated  by  dialysis,  which  coagulated 
at  .')0-GU°  C.  and  also  showed  certain  similarities  with  Klhnk's  myosin. 
A  spontaneously  coagulating  albumin,  which  differed  from  myogen 
(v.  FiJRTii)  by  coagulating  at  45-50°  C.  and  which  passes  in  spontaneous 
coagulation  into  the  coagulated  modification  w^ithout  a  sohible  intermediate 
product,  exists  in  still  greater  quantities  in  tliis  plasma.  Alkali  albuminates 
do  not  occur,  but  a  nucleoproteid  is  found,  which  exists  in  about  five  times 
the  (juantity  as  compared  with  non-striated  muscles. 

Hcemoglohi)i,  occurs  in  the  smooth  muscles  of  certain  animals,  but  is 
absent  in  others.  Crcatin  has  been  found  by  Lehmaxx.'  According  to 
Fkemy  and  Valenciennes  '  the  muscles  of  the  Cephalopods  contain 
taurin  besides  creatinin  [creatin?).  Of  the  non-nitrogenous  substances, 
glycogen  and  lactic  acid  have  been  found  without  doubt.  The  mineral  con- 
stituents show  the  remarkable  fact  that  the  sodium  combinations  exceed  the 
potassium  combinations. 

>  Centralbl.  f.  Physiol.,  Bd.  13,  S.  351. 

»  Cited  from  Nasse,  1.  c,  S.  339. 

»  Cited  from  KUhue's  Lehrbuch.S.  333. 


CHAPTEE  XII. 
BRAIN  AND   NERVES. 

On  account  of  the  difficulty  of  making  a  mechanical  separation  and 
isolation  of  the  different  tissue-elements  of  the  nervous  central  organ  and 
the  nerves,  we  must  resort  to  a  few  microchemical  reactions,  chiefly  to 
qualitative  and  quantitative  investigations  of  the  different  parts  of  the 
brain,  in  order  to  study  the  varied  chemical  comf)osition  of  the  cells  and 
the  nerve-tubes.  This  study  is  accompanied  with  the  greatest  difficulty; 
and  although  our  knowledge  of  the  chemical  composition  of  the  brain  and 
nerves  has  been  somewhat  extended  by  the  investigations  of  modern  times, 
still  we  must  admit  that  this  subject  is  as  yet  one  of  the  most  obscure  and 
complicated  in  physiological  chemistry. 

Froteids  of  different  kinds  have  been  shown  to  be  chemical  constituents 
of  the  brain  and  nerves.  Some  of  them  are  insoluble  in  water  and  dilute 
neutral-salt  solutions,  and  some  are  soluble  therein.  Among  the  latter  we 
find  albumin  and  globulin.  Nucleoalbumin,  which  is  often  considered  as 
an  alkali  albuminate,  also  occurs.  Halliburton  '  found  two  globulins  in 
the  brain,  one  of  which  coagulates  at  47-50°  C,  and  the  other  at  70°  C. 
He  found  in  the  gray  matter  a  nucleoalbumin  which  coagulated  at 
55-60°  C.  and  contained  0.5^  phosphorus.  It  seems  unquestionable  that 
the  albuminous  bodies  belong  chiefly  to  the  gray  substance  of  the  brain 
and  to  the  axis-cylinders.  The  same  remarks  apply  to  mcclein,  which 
V.  Jacksch  "^  found  in  large  quantities  in  the  gray  substance.  Neurokerati7i 
(see  page  51),  which  was  first  detected  by  KiJnNE,  and  which  partly  forms 
the  neuroglia,  and  which  as  a  double  sheath  envelops  the  outside  of  the 
nerve  medulla  under  Schwann's  sheath  and  the  inner  axis-cylinders,  chiefly 
occurs  in  the  white  substance  (Kuitne  and  Chittenden,  Baumstaek'). 

The  phosphorized  substance  protagon  must  be  considered  as  one  of  the 
chief  constituents,  perhaps  the  only  constituent  (Baumstark),  of  the  white 
substance.     This  last-mentioned  substance,  if  we  keep  for  the  present  to 

'  On  the  Chemical  Physiology  of  llie  Aniinul  Cell.  Kiug's  College,  London,  Phys- 
iological Laboratory.     Collecled  Papers,  No.  1 ,  1893. 

'  Pfluger's  Arch.,  Bd.  13. 

M^^iihne  and  Chittenden,  Zeitschr.  f.  Biologie,  Bd.  26;  Baumstark,  Zeilschr. 'f, 
physiol.  Cbem.,  Bd.  9. 

358 


CONSTITUTION  OF  BRAIN  AND  NERVES.  359 

the  most  carefully  studied  protagou — because  there  are  perhaps  several 
<lifferent  protagons — yields  as  decomposition  products  lecithin,  fatty  acids, 
and  a  nitrogenous  substance,  cerehrin ;  this  last  probably  does  not  occur 
preformed  in  tlie  brain,  but  is  more  likely  a  product  of  transformation. 
That  lecithin  also  is  pre-existent  in  the  brain  and  nerves  can  hardl}'  be 
doubted.  The  investigations  thus  far  made  have  not  sliown  decidedly 
whether  it  is  more  abundant  in  the  gray  or  the  wliite  su])stance.  Falty 
acids  and  neutral  fats  may  be  prepared  from  the  brain  and  nerves;  but  as 
these  may  be  readily  derived  from  a  decomposition  of  lecithin  and  ])rotagon, 
which  exist  in  the  fatty  tissue  between  the  nerve-tubes,  it  is  diilicult  to 
decide  what  part  the  fatty  acids  and  neutral  fats  play  as  constituents  of  the 
real  nerve-substance.  Cholesterin  is  also  found  in  the  brain  and  nerves,  a 
part  free  and  a  part  in  chemical  combination  of  unknown  constitution 
(Baumstark).  Cholesterin  seems  to  occur  in  greater  abundance  in  the 
white  substance.  Besides  these  substances  the  nerve  tissue,  especially  the 
white  substance,  contains  doubtless  a  number  of  other  constituents  not 
well  known,  and  among  which  are  several  containing  phosphorus.  Thudi- 
riiuM  asserted  that  he  had  isolated  a  number  of  phosphorized  substances 
from  the  brain  which  he  divided  into  tliree  principal  groups:  kepalines, 
myelifies,  and  hcithines.^  But  thus  far  this  assertion  has  not  been  confirmed 
by  other  investigators. 

By  allowing  water  to  act  on  the  contents  of  the  medulla,  round  or 
oblong  double-contoured  drops  or  fibres,  not  unlike  double-contoured 
nerves,  are  formed.  This  remarkable  formation,  which  can  also  be  seen  in 
the  medulla  of  the  dead  nerve,  has  been  called  "  viyeliue  forms.,''''  and  they 
were  formerly  considered  as  produced  from  a  special  body,  "  myeline." 
Myeliue  forms  may,  however,  be  obtained  from  other  bodies,  such  as  impure 
protagon,  lecithin,  fat,  and  impure  cholesterin,  and  they  depend  on  a 
decomposition  of  the  constituents  of  the  medulla.  According  to  Gad  and 
IIeymaxs*  myeline  is  lecithin  in  a  free  condition  or  in  loose  chemical  com. 
binatiou. 

The  extractive  bodies  seem  to  be  almost  the  same  as  in  the  muscles. 
We  find  creatin,  which  may,  however,  be  absent  (Baumstark),  xanthin 
bodies,  iiiosit,  lactic  acid  (also  fermentation  lactic  acid),  i(ric  acid.,  jecorin 
^according  to  Baldi,"  in  the  human  brain),  and  the  diamin  nenridi?i, 
CJI,,X, ,  discovered  by  BRiE(iER*  and  which  is  most  interesting  because  of 
its  appearance  in  the  putrefaction  of  animal  tissues  or  in  cultures  of  the 
typhoid  bacillus.     Under  pathological  conditions  leiicin  and  nrea  have  been 

'  Thmiiclmni.  GrundzHge  der  auatom.  und  klin.  Cbem.,  Berlin,  1886,  aud  Journ.  f. 
prakt.  Cliem.  (N.  F.).  Bd.  53. 

'  Du  Bois-Reymond's  Arch.,  1890. 

«  Ibid..  1887/Siipplbd. 

*  Brieger,  Uchcr  Ptomaine.     Berlin,  1885  aud  1886. 


360  BBAIN  AND  NERVES. 

fouud  in  the  brain.  Urea  is  also  a  physiological  constituent  of  the  brain  of 
cartilaginous  fishes.  According  to  the  researches  of  Gulewitsch  '  no 
nenrin  occurs  in  fresh  ox-brains,  nor  ia  it  formed  in  the  cleavage  of  pro- 
tagon.  The  different  results  obtained  by  Liebreich  depends,  according  to 
him,  upon  his  not  having  analyzed  a  pure  preparation  of  cholin  platinum 
chloride.  GuLEWiTSCH  found  urea  and  two  not  studied  leucomaines  in 
the  watery  extract  of  brains. 

Of  the  above-mentioned  constituents  of  me  nerve-sabstance  protagon 
and  its  decomposition  products,  the  cerebrins  or  cerebrosides,  must  be 
specially  described. 

Protagon.  This  body,  which  was  discovered  by  Liebreich,  is  a  nitrog- 
enized  and  phosphorized  substance  whose  elementary  composition,  accord- 
ing to  Gamgee  and  Blaxkenhorn,  is  C  66.39,  H  10.69,  IST  2.39,  and 
P  1.068  per  cent.  Baumstark  and  Euppel  obtained  the  same  figures,  while 
Liebreich  found  an  average  of  2.80^  N  and  1.23^  P.  Kossel  and 
Frettag,°  who  obtained  still  higher  figures  for  the  nitrogen,  namely,  3.25^,. 
and  somewhat  lower  figures  for  the  phosphorus,  0.97^,  found  some  sulphur, 
an  average  of  0.51^,  regularly  in  the  protagon.  Euppel  also  found  some 
sulphur,  but  in  such  small  quantity  that  he  considered  it  as  a  contamina- 
tion. 0n  boiling  with  baryta-water  protagon  yields  the  decomposition 
prodncts  of  lecithin,  namely,  fatty  acids,  glycerophosphoric  acid,  and  cholin 
(neurin?),  and  besides  this  also  cerebrin.  Kossel  and  Freytag  found  that 
protagon  not  only  yielded  cerebrin  in  its  decomiDosition,  but  two  and  perhaps 
indeed  three  cerebrosides  (see  below),  namely,  cerebri^,  kerasiist  (homo- 
cerebrin),  and  encephalic.  Because  of  this  behavior,  and  also  because  of 
the  varying  elementary  composition  although  the  greatest  care  was  taken  in 
the  i^reparation,  Preytag  considers  it  very  probable  that  there  are  several 
protagons. 

On  boiling  with  dilute  mineral  acids,  protagon  yields  among  other  sub- 
stances a  reducing  carbohydrate.  On  oxidation  with  nitric  acid  protagon 
yields  higher  fatty  acids. 

Protagon  appears,  when  dry,  as  a  loose  white  powder.  It  dissolves  in 
alcohol  of  85  vols,  per  cent  at  +  45°  C,  but  separates  on  cooling  as  a  snow- 
white,  flaky  precipitate,  consisting  of  balls  or  groups  of  fine  crystalline 
needles.  It  decomposes  on  heating  even  below  100°  C.  It  is  hardly  soluble 
in  cold  alcohol  or  ether,  but  dissolves  on  warming.  It  swells  in  little  water, 
and  partly  decomposes.  With  more  water  it  swells  to  a  gelatinous  or  pasty 
mass,  which  with  much  water  yields  an  opalescent  liquid.  On  fusing  with 
saltpetre  and  soda,  alkali  phosphates  are  obtained. 

>  Zeitschr.  f.  pbysiol,  Chem.,  Bd.  27. 

*  Gamgee  and  BlankenborD,  Zeitschr.  f.  physiol.  Chem.,  ;Bd.  3  ;  Baumstark,  1.  c.;. 
Ruppel,  Zeitschr.  f.  Biologic,  Bd.  31;  Liebreich,  Anual.  d.  Chem.  u.  Pbarm.,  Bd.^ 
134;  Kossel  and  Freytag,  Zeitschr,  f.  pbysiol.  Chem.,  Bd.  17. 


PROTAGON  AND   CEltEBRIN.  361 

Protagon  is  prepared  in  tlie  following  way:  Au  ox-brain  as  fresh  as 
possible,  with  the  blood  and  membranes  earefull}'  removed,  is  ground  fine 
and  then  extracted  for  several  hours  with  alcohol  of  80  vols,  per  cent  at 
+  45°  C,  iiltered  at  the  same  temperature,  and  the  residue  extracted  with 
warm  alcohol  until  the  filtrate  does  not  yield  a  ])recipitate  at  0°  C.  The 
several  alcoholic  extracts  are  cooled  to  0°  C.  and  the  precipitates  united  and 
conij)letely  extracted  with  cold  ether,  whicli  dissolves  the  cholesterin  and 
lecithin-like  bodies.  The  residue  is  now  strongly  pressed  between  filter- 
paper  and  allowed  to  dry  over  sulphuric  acid  or  phosphoric  anhydride.  It 
is  now  ])iilverized,  digested  with  alcohol  at  +  -^5°  C,  filtered  and  slowlv 
cooled  to  0°  C.  The  crystals  which  separate  may  be  purified  when  necessary 
by  recrystallization. 

The  same  steps  are  taken  when  we  wish  to  detect  the  presence  of 
protagon. 

On  decomposing  protagon  or  the  protagons  by  the  gentle  action  of 
alkalies  we  obtain  as  cleavage  products,  as  above  stated,  one  or  more  bodies, 
which  TiiUDiciiUM  has  embraced  under  the  name  cerehrosides.  The  cere- 
brosides  are  nitrogenous  substances  free  from  phosphorus,  whicli  yield  a 
reducing  variety  of  sugar  (galactose)  on  boiling  with  dilute  mineral  acids. 
On  fusing  with  potash  or  by  oxidation  with  nitric  acid  they  yield  higher 
fatty  acids,  palmitic  or  stearic  acids.  The  cerehrosides  isolated  from  the 
brain  are  cerebrin,  kerasin,  and  encephalin.  The  bodies  isolated  by  Kossel 
and  Fkeytag  from  pus,  pyosiu  and  pyogenin  also  belong  to  the  cere- 
hrosides. 

Cerebrin;  Under  this  name  W.  Muller*  first  described  a  nitrogenous 
substance,  free  from  phosphorus,  which  he  obtained  by  extracting  a  brain- 
mass,  which  had  been  previously  boiled  with  baryta-water,  with  boiling 
alcohol.  Following  a  method  essentially  the  same,  but  differing  somewhat, 
Geoghegan^  prepared  from  the  brain  a  cerebrin  with  the  same  properties 
as  MuLLEu's,  but  containing  less  nitrogen.  According  to  Parous'  the 
cerebrin  isolated  by  Geogiiegan  as  well  as  by  Muller  consists  of  a  mixture 
of  three  bodies,  "  cerebrin,"  "  homocerebriu,"  and  "  encephalin."  KossEL 
and  Freytag  isolated  two  cerehrosides  from  protagon  which  were  identical 
with  the  cerebrin  and  homocerebriu  of  Parous.  According  to  these  inves- 
tigators the  two  bodies  phrenosin  and  kerasin  as  described  by  Thudichum 
seem  to  be  identical  with  cerebrin  and  homocerebriu. 

Cerebrin,  according  to  Parous,  has  the  following  composition:  C  69.08, 
H  11.47,  N  2.13,  0  17.32j^,  which  corresponds  with  the  analyses  made  by 
Kossel  and  Freytag.  No  formula  has  been  given  to  this  body.  In  the 
dry  state  it  forms  a  pure  white,  odorless,  and  tasteless  powder.  On  heating 
it  melts,  decomposes  gradually,  smells  like  burnt  fat,  and  burns  with  a 

1  Annal.  d.  Chem.  u.  Pbarm.,  Bd.  105. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  3. 

=  Parcus,  Ueber  einige  iieue  Gehirustoffe.     luaug.-Diss.  Leipzig,  1881. 


362  BRAIN  AND  NERVES. 

luminous  flame.  It  is  insoluble  in  water,  dilute  alkalies,  or  baryta-water. 
It  is  also  insoluble  in  cold  alcohol  and  in  cold  or  hot  ether.  On  the  con- 
trary, it  is  soluble  in  boiling  alcohol  and  separates  as  a  flaky  precipitate  on 
cooling,  and  this  is  found  to  consist  of  a  mass  of  balls  or  grains  on  micro- 
scopical examination.  Cerebrin  forms  witli  baryta  a  compound,  insoluble 
in  water,  which  decomposes  by  the  action  of  carbon  dioxide.  Cerebrin 
dissolves  in  concentrated  sulphuric  acid,  and  on  warming  the  solution  it 
becomes  blood-red.  The  variet}^  of  sugar  split  off  on  boiling  with  mineral 
acids — the  so-called  brain-sugar — is,  according  to  Thieefelder,'  galactose. 
Kerasin  (according  to  Thudichum)  or  liomocerehrin  (according  to 
Parous)  has  the  following  composition:  C  70.06,  H  11.00,  IST  2.23,  and 
0  IG.llj^.  Enceplialin  has  the  composition  C  68.40,  H  11.60,  N  3.09,  and 
0  16.91^.  Both  bodies  remain  in  the  mother-liquor  after  the  impure 
cerebrin  has  precipitated  from  the  warm  alcohol.  These  bodies  have  the 
tendency  of  separating  as  gelatinous  masses.  Kerasin  is  similar  to  cerebrin, 
but  dissolves  more  easily  in  warm  alcohol  and  also  in  warm  ether.  It  may 
be  obtained  as  extremely  flne  needles.  Encephalin  is,  according  to  Parcus, 
a  transformation  product  of  cerbrin.  In  the  perfectly  pure  state  it  crystal- 
lizes in  small  lamellae.  It  swells  into  a  pasty  mass  in  warm  water.  Like 
cerebrin  and  kerasin,  it  yields  a  reducing  substance  (probably  galactose)  on 
boiling  with  dilute  acid. 

The  cerebrins  are  generally  prepared  according  to  Muller's  method. 
The  brain  is  first  stirred  with  baryta-water  until  it  appears  like  thin  milk, 
and  then  it  is  boiled.  The  insoluble  parts  are  removed,  pressed,  and 
repeatedly  boiled  with  alcohol,  which  is  filtered  while  boiling  hot.  The 
impure  cerebrin  which  separates  on  cooling  is  freed  from  cholesterin  and  fat 
by  means  of  ether,  and  then  purified  by  repeated  solution  in  warm  alcohol. 
According  to  Parcus  this  repeated  solution  in  alcohol  is  continued  until  no 
gelatinous  separation  of  homocerebrin  or  encephalin  takes  place. 

According  to  Geoghegan's  method  the  brain  is  first  extracted  with  cold 
alcohol  and  ether  and  then  boiled  with  alcohol.  The  precipitate  which 
separates  on  tbe  cooling  of  the  alcoholic  filtrate  is  treated  with  ether  and 
then  boiled  with  baryta-water.  The  insoluble  residue  is  purified  by  repeated 
solution  in  boiling  alcohol. 

The  cerebrin  may  also  be  obtained  from  other  organs  by  employing  the 
above  methods.  The  quantitative  estimation,  when  such  is  desired,  may  be 
performed  in  the  same  way. 

KossEL  and  Freytag  prepare  cerebrin  from  protagon  by  saponifying  it 
in  a  solution  in  methyl  alcohol  with  a  hot  solution  of  caustic  baryta  in 
methyl  alcohol.  The  precipitate  is  filtered  off  and  decomposed  in  water  by 
carbon  dioxide,  and  the  cerebrin  or  cerebroside  extracted  from  the  insoluble 
residue  by  hot  alcohol. 

Neuridin,  CiUmNs,  is  a  noii-poisonous  tliamin  discovered  by  Biueger,  and  wliich 
was  obiaiued  by  Lira  iu  the  putrefaction  of  meal  and  gelatin,  and  from  cultures  of  the 
typhoid  bacillus.  It  also  occurs  under  physiological  conditions  in  the  brain,  and  as 
traces  in  the  yolk  of  the  egg. 

'  Zeitschr.  f.  physiol.  Cheoi.,  Bd.  14. 


COMPOSITION  OF   THE  DUAIN.  863 

Noiiridiii  dissolvos  in  water,  and  yields  on  Ijoilini^  wltli  alkalies  a  niixtiirc  of 
<liinetliylaniiu  and  trimetliylaniin.  It  dissolves  with  diilicidty  in  ;iniyl-alcoliol.  It  is 
insoluble  in  etlier  or  absolute  alcoiiol.  In  the  free  stale  neuiidin  has  a  ])eculiar  odoi, 
sufjijesting  semen.  Willi  hydroehloiic  acid  it  {iiv«s  a  combination  ciystaliizing  in  loni^ 
needles.  Willi  platinic  chloride  or  gold  chloride  it  gives  ciysialli/.ubie  double  combina- 
lions  which  are  valuable  in  iis  preparation  and  deieciion. 

The  so-called  roupnsci'i.A  amyt,ack.\,  which  occur  on  the  upper  surface  of  tlie 
brain  and  in  llie  pituitary  gland,  are  colored  more  or  less  pure  violet  by  iodine  and 
more  blue  by  sulphuric  acid  and  iodine.  They  consist,  peiliaps,  of  the  same  subsiuucu 
as  certain  prostatic  calculi,  but  they  have  not  been  closely  investigated. 

Quantitative  Comjwsition  of  the  Brain.  The  quantity  of  water  is 
greater  in  the  gray  than  in  the  white  substance,  and  greater  in  new-born 
or  young  individuals  than  in  adults.  The  brain  of  the  fcptus  contains 
870-020  p.  m.  water.  According  to  the  observations  of  Weisrach  '  the 
quantity  of  water  in  the  several  parts  of  tlie  brain  (and  in  the  medulla)  varies 
at  different  ages.  The  following  figures  are  in  1000  parts — A  for  men  and 
B  for  women: 

20-.30  Years.  30-.".0  Year.<.  50-70  Yea r.s.  TO-94  Ye;,rs 

Whitesubstanceof  the  brain  695.6  682.9  683.1  703.1  701.9  689.6  7136  1  7',''2.0 

Gray  ditto 833.6  826  3  836.1  830.6  838.0  838.4  847  8  839.5 

Gyri -...784  7  792  0  795.9  772.9  796.1  796  9  802.3  801.7 

Cerebellum   788.3  794.9  778  7  789.0  787.9  784.5  803.4  797.9 

Pons  Varolii 734.6  740.3  725.5  722.0  720.1  714.0  727.4  724.4 

Medulla  ol)longata 744.3  740.7  732.5  729.8  722.4  730.6  736.2  733.7 

Quantitative  analyses  of  the  brain  have  also  been  made  by  Petrowsky' 
on  an  ox-brain,  and  by  Baumstark  on  the  brain  of  a  horse.  In  the  analysis 
of  Petkowsky  the  protagon  has  not  been  considered,  and  all  organic,  phos- 
phorized  substances  were  calculated  as  lecithin.  On  these  grounds  these 
analyses  are  not  of  much  value  from  a  certain  standpoint.  In  Baumstaiik's 
analyses  the  gray  and  the  white  substance  could  not  be  sufficiently  separated, 
and  these  analyses,  on  this  account,  show  partly  an  excess  of  white  and 
partly  an  excess  of  gray  substance;  nearly  one  half  of  the  organic  bodies, 
chielly  consisting  of  bodies  soluble  in  ether,  could  not  be  exactly  analyzed, 
Keither  of  these  analyses  gives  sufficient  explanation  of  the  quantitative 
composition  of  the  brain. 

The  analyses  made  up  to  the  present  time  give,  as  above  stated,  an 
unequal  division  of  the  organic  constituents  in  the  gray  and  white  substance. 
In  the  analyses  of  Petrowsky  the  quantity  of  proteids  and  gelatin-forming 
substances  in  the  gray  matter  was  somewhat  more  than  one  half,  and  in  the 
white  about  one  quarter,  of  the  solid  organic  substances.  The  quantity  of 
cholesterin  in  the  white  was  about  one  half,  and  in  the  gray  substance  about 
one  fifth,  of  the  solid  bodies.  A  greater  quantity  of  soluble  salts  and 
extractive  bodies  was  found  in  the  gray  substance  than  in  the  white 
(Baumstark).     The  following  analyses  of  Baumstark  give  the  most  im- 

«  Cited  from  K.  B.  Hofmann's  Lehrb.  d.  Zoocbemie  (Wien.  1876),  S.  121. 
'  Pfliiger's  Arch.,  Bd.  7. 


364  BRAIN  AND  NERVES. 

portant  known  constituents  of  the  brain  calculated  in  1000  parts  of  the 
fresh,  moist  brain.  A  represents  chiefly  the  white,  and  B  chiefly  the  gray, 
substance. 

A.  B. 

Water 695.35  769.97 

Solids 304.65  230.03 

ProtJigon 25.11  10.80 

Insoluble  proteid  aud  couaective  tissue 50.03  60.79 

Cbolesteriu,  free 18.19  6.30 

combined •.  26.96  17.51 

Nucleiu 2.94  1.99 

Neurokeratin ,. 18.93  10.43 

Mineral  bodies  5.23  5.62 

The  remainder  of  the  solids  probably  consists  chiefly  of  lecithin  and 
other  pliosphorized  bodies.  Of  the  total  amount  of  phosphorus  15-20 
p.  m.  belongs  to  the  nuclein,  oO-GO  p.  m.  to  the  protagon,  150-1  GO  p.  m. 
to  the  ash,  and  770  p.  m.  to  the  lecithin  and  the  other  phosphorized  organic 
substances. 

The  quantity  of  neurokeratin  in  the  nerves  and  in  the  different  parts  of 
the  brain  has  been  car.efully  determined  by  Kuhne  and  Chittenden".! 
They  found  3.16  p.  m.  in  the  plexus  brachialis,  3.12  p.  m.  in  the  edge  of 
the  cerebellum,  22.434  p.  m.  in  the  white  substance  of  the  cerebrum, 
25.72-29y02  p.  m.  in  the  white  substance  of  the  corpus  callosum,  and  3.27 
p.  m.  m.  the  gray  substance  of  the  edge  of  the  cerebrum  (when  free  as 
possible  from  Avhite  substance).  The  white  is  very  considerably  richer  in 
neurokeratin  than  the  peripheric  nerves  or  the  gray  substance.  According 
to  Griffiths'^  neurochi tin  replaces  neurokeratin  in  insects  and  Crustacea, 
the  quantity  of  the  first  being  lO.G-12  p.  m. 

The  quantity  of  mineral  constitents  in  the  brain  amounts  to  2.95-7.08 
p.  m.  according  to  Geoghegan.  He  found  in  1000  parts  of  the  fresh, 
moist  brain  0.43-1.32  CI,  0.956-2.010  PO,,  0.244-0.79G  CO3,  0.102-0.220 
SO,,  0.01-0.098  Fe,(POJ,,  0.005-0.022  Ca,  0.016-0.072  Mg,  0.58-1.778 
K,  0.450-1.114  Na.  The  gray  substance  yields  an  alkaline  ash,  the  white 
an  acid  ash. 

Appeudix. 

The  Tissue  and  Fluids  of  the  Eye. 

The  retina  contains  in  all  865-899.9  p.  m.  water,  57.1-84.5  p.  m.. 
^roteid  bodies — myosin,  albumin,  and  mucin  (?),  9.5-28.9  p.  m.  lecithin, 
and  8.2-11.2  p.  m.  salts  (Hoppe-Seyler  and  Cahn").  The  mineral  bodies 
consist  of  422  p.  m.  Na,IIPO,  and  352  p.  m.  NaCI. 

Those  bodies  which  form  the  different  segments  of  the  rods  and  cones 

'  Zeitsclir.  f.  Biologie,  Bd.  26. 

'  Compt.  rend.,  Tome  115. 

*  Zeitscbr.  f.  physiol.  Cbem.,  Bd.  5. 


VISUAL   PURPLE.  365 

have  not  been  closely  studied,  and  the  greatest  interest  is  therefore  con- 
nected with  the  coloring  matters  of  the  retina. 

Visual  purple,  also  called  rhodopsin,  erythropsin,  or  visual  red,  is  the 
pigment  of  the  rods.  Boll'  observed  in  1870  that  the  layer  of  rods  in  the 
retina  during  life  had  a  purplish-red  color  which  was  bleached  by  the  action 
of  light.  KuuNE  '  showed  later  that  this  red  color  might  remain  for  a  long 
time  after  the  death  of  the  animal  if  they  eye  was  protected  from  daylight 
or  investigated  by  a  sodium  light.  lender  these  conditions  it  was  also 
possible  to  isolate  and  closely  study  this  substance. 

Visual  red  (Boll)  or  visual  purple  (Kuiixe)  has  become  known  mainly 
by  the  investigations  of  Kuiixe.  The  pigment  occurs  chiefly  in  the  rods 
and  only  in  their  outer  parts.  In  animals  whose  retina  has  no  rods  the 
visual  purple  is  absent,  and  is  also  necessarily  absent  in  the  macula  lutea. 
In  a  variety  of  bat  [rhinolophus  Jiipposideros),  in  hens,  pigeons,  and  new- 
born rabbits,  no  visual  purple  has  been  found  in  the  rods. 

A  solution  of  visual  purple  in  Avater  which  contains  2-5^  crystallized 
bile,  which  is  the  best  solvent  for  it,  is  purple-red  in  color,  quite  clear,  and 
not  fluorescent.  On  evaporating  this  solution  in  vacuo  we  obtain  a  residue 
similar  to  ammonium  carminate  which  contains  violet  or  black  grains.  If 
the  above  solution  is  dialyzed  with  water,  the  bile  diffuses  and  the  visual 
purple  separates  as  a  violet  mass.  Under  all  circumstances,  even  when  still 
in  the  retina,  the  visual  purple  is  quickly  bleached  by  direct  sunlight,  and 
with  diffused  light  with  a  rapidity  corresponding  to  the  intensity  of  the 
light.  It  passes  from  red  and  orange  to  yellow.  Red  light  bleaches  the 
visua'  purple  slowly;  the  ultra-red  ligbt  does  not  bleach  it  at  all.  A  solu- 
tion of  visual  purple  shows  no  special  absorption-bands,  but  only  a  general 
absorption  which  extends  from  the  red  side,  beginning  at  D,  to  the  line  G. 
The  strongest  absorption  is  found  at  F. 

KoETTGEN  and  ABEL8DOISF  5  luive  showD  that  we  have,  in  accordance  with  Kuhne's 
views,  two  variities  of  visual  purple,  tlie  one  occurriu!^  in  uiauiinals,  birds,  and  amiiliib- 
ians,  and  the  other,  whicli  is  more  violet-red,  in  fishes.  The  first  has  its  maximum 
absorption  in  the  green,  and  the  other  in  the  yellowish  green. 

Vi.sual  purple  when  heated  to  52-53°  C.  is  destroyed  after  several  hours, 
and  almost  instantly  when  heated  to  +  76°  C.  It  is  also  destroyed  by 
alkalies,  acids,  alcohol,  ether,  and  chloroform.  On  the  contrary,  it  resists 
the  action  of  ammonia  or  alum  solution. 

As  the  visual  purple  is  easily  destroyed  by  light,  it  must  therefore  also 
be  regenerated  during  life.     Kuhne  has  also  found  that  the  retina  of  the 

'  Monatsschr.  d.  Berl.  Akad.,  13  Nov.,  1876. 

'  The  investigations  of  Klihne  and  his  pupils  Ewald  and  Ayres  on  tlie  visual  purple 
will  be  found  in  Untersuchungen  aus  dem  phjsiol.  Institiit  der  Universitiit  Heidelberg, 
Bdd.  1  und  2.  and  in  Zeitschr.  f.  IJiologie,  Bd.  .'^2. 

•  Centralbl.  f.  Phj'.Mol.,  Bd.  9,  also  Maly's  Jahresbcr.,  Bd.  25,  S.  351. 


366  BBAIN  AND  NERVES. 

eye  of  the  frcg  becomes  bleached  when  exposed  for  a  long  time  to  strong 
suulio-ht.,  and  that  its  color  gradually  retnrns  when  the  animal  is  placed  in 
the  dark.  This  regeneration  of  the  visual  pnrple  is  a  function  of  the  living 
cells  in  the  layer  of  the  pigment-epithelium  of  the  retina.  This  may  be 
inferred  from  the  fact  that  a  detached  piece  of  the  retina  which  has  been 
bleached  by  light  may  have  its  visual  purple  restored  if  the  detached  piece 
of  the  retina  be  carefully  laid  on  the  chorioidea  having  layers  of  the 
pigment-epithelium  attached.  The  regeneration  has,  it  seems,  nothing  to 
do  with  the  dark  pigment,  the  melanin  or  fnscin,  in  the  epithelium-cells. 
A  partial  regeneration  seems,  according  to  Kuhn"e,  to  be  possible  in  the 
completely  removed  retina.  On  account  of  this  property  of  the  visual 
purple  of  being  bleached  by  light  during  life  we  may,  as  Kuhne  has  shown, 
under  special  conditions  and  by  observing  special  precautions,  obtain  after 
death  by  the  action  of  intense  light  or  more  continuous  light  the  picture  of 
brio-ht  objects,  such  as  windows  and  the  like — so-called  optograms. 

The  physiological  importance  of  visual  purple  is  unknown.  It  follows 
that  the  visual  pnrple  is  not  essential  to  sight,  since  it  is  absent  in  certain 
animals  and  also  in  the  cones. 

Visual  purple  must  always  be  prepared  exclusively  in  a  sodium  light. 
It  is  e^racted  from  the  net  membrane  by  means  of  a  watery  solution  of 
crystallized  bile.  The  filtered  solution  is  evaporated  in  vacuo  or  dialyzed 
until  the  visual  purple  is  separated.  To  prepare  a  visual-purple  solution, 
perfectly  free  from  hemoglobin,  the  solution  of  visual  purple  in  choliates  is 
precipitated  by  saturating  with  magnesium  sulphate,  washing  the  precipitate 
with  a  saturated  solution  of  magnesium  sulphate,  and  then  dissolving  in 
water  by  the  aid  of  the  simultaneously  precipitated  choliates." 

The  Pigments  of  the  Cones.  In  the  inner  segments  of  the  cones  of  llbirds,  reptiles, 
and  fishes  a  small  fat-globule  of  varying  color  is  found.  Ktdhne'  has  isolated  from  this 
fat  a  green,  a  yellow,  and  a  red  pigment  called  respectively  cMuroplian,  xanthopan,  and 
rhodophdn. 

The  dark  pigment  of  the  epithelium- cells  of  the  net  membrane,  which  was  for- 
merly called  7nelanin,  but  since  named /(wcm  by  Kvjhne  and  May,^  dissolves  in  concen- 
trated caustic  alkalies  or  concentrated  sulphuric  acid  on  warming,  but,  like  melauins  in 
general  (see  Chapter  XVI).  has  been  little  studied.  The  pigment  occurring  in  the 
pigmeut-cclls  of  the  chlorioidea  seems  to  be  identical  with  the  fusciu  of  the  reiina. 

The  vitreous  humor  is  often  considered  as  a  variety  of  gelatinous  tissue. 

The  membrane  consists,  according  to  0.   Morner,'  of  a  gelatin-forming 

substance.     The  fluid  contains  a  little  proteid  and  a  mucoid,  hyalomucoid, 

which  was  first  shown  by  Morner,  and  which  is  not  precipitated  by  acetic 

acid.     This  contains  12.27,'^  N  and  1.19^  S.     Among  the  extractives  we 

find  a  little  lirea— according  to  Pica.rd'  5  p.  m.,  according  to  Rahlmank  ' 

>  Kuhne,  Zeitschr.  f.  Biologip,  Bd.  32. 

»  Kliiine.  Die  nichtbcslilndigen  Farben  der  Nelzhaut.     Untersuch.  aus  dem  physiol. 
Institut  Heidelberg,  Bd.  1.  S.  341. 
»  Kiihne,  ibid.,  Bd.  2,  S   324. 

*  Zeitschr.  f.  physiol.  Ohcm.,  Bd.  18. 

*  Gam  gee's  Physiol.  Chcm.,  p.  454. 
6  Maly'3  Jahresber.,  Bd.  6,  S.  219. 


CRYSTALIJyK  LENS.  367 

0.04  p.  m.  Pactz  '  fonnd  besides  some  urea  also  paralactic  acid,  and,  ia 
confirmation  of  tlie  statements  of  Chabbas,  Jesnkr,  and  Kuiix,  also 
glucose  in  the  vitreons  hnmor  of  oxen.  The  reaction  of  the  vitreons  humor 
is  alkaline,  and  the  quantity  of  solids  amounts  to  about  1 1  p.  m.  Tlie 
quantity  of  mineral  bodies  is  about  9  p.  m.,  and  the  albuminous  bodies  0.7 
p.  m.     In  reirard  to  the  aqueous  liumor  see  page  104. 

The  Crystalline  Lens.  That  substance  which  forms  the  capsule  of  tiie 
lens  has  been  recently  investigated  by  C.  ;Morxp:i{.  It  belongs,  accord- 
ing to  him,  to  a  special  group  of  proteins,  called  inevihranins.  The 
membranin  bodies  are  insoluble  at  the  ordinary  temperature  in  water,  salt 
solutions,  dilute  acids,  and  alkalies,  and,  like  the  mucins,  yield  u  reducing 
substance  on  boiling  with  dilute  mineral  acids.  They  contain  sulphur, 
which  blackens  lead.  The  membranins  are  colored  a  very  beautiful  red  by 
MiLLOX's  reagent,  but  give  no  characteristic  reaction  with  concentrated 
hydrochloric  acid  or  Adamkiewicz's  reagent.  They  are  dissolved  with 
great  difficulty  by  pepsin-hydrochloric  acid  or  trypsin  solution.  Thev  are 
dissolved  by  dilute  acids  and  akalies  in  the  warmth.  Membranin  of  the 
capsule  of  the  lens  contains  14.10,''^  X  and  0.83^  S,  and  is  a  little  less  soluble 
than  that  from  Descemet's  membrane. 

The  chief  mass  of  the  solids  of  the  crystalline  lens  consists  of  proteids, 
whose  nature  has  been  investigated  by  C.  Mokner.'  Some  of  these  proteids 
are  insoluble  in  dilute  salt  solution,  and  others  soluble  therein. 

The  Insoliible  Proteid.  The  lens-fibres  consist  of  a  proteid  substance 
which  is  insoluble  in  water  and  salt  solution  to  which  Mokxer  has  o-iven 
the  name  albumoid.  It  dissolves  readily  in  very  dilute  acids  or  alkalies. 
Its  solution  in  caustic  potash  of  0.1^  is  very  similar  to  an  alkali-albuminate 
solution,  but  coagulates  at  about  50°  C.  on  nearly  complete  neutralization 
and  addition  of  8^  XaCI.  Albnmoid  has  the  following  composition: 
C  53.12,  H  6.8,  N  1G.62,  and  S  0.79^.  The  lens-fibres  themselves  contain 
1(5.61^  N  and  0.77^  S,  The  inner  parts  of  the  lens  are  considerably  richer 
in  albumoid  than  the  outer.  The  quantity  of  albnmoid  in  the  entire  lens 
amounts  on  an  average  to  about  48^  of  the  total  weight  of  proteids  of  the 
lens. 

Tlie  Soluble  Proteid  consists,  exclusive  of  a  very  small  cr.antity  of 
ALBUMix,  of  two  globulins,  a-  and  /?-crystallix.  These  two  globulins 
differ  from  each  other  in  this  manner:  o'-crystallin  contains  10,68^  X  and 
O.oG,'^  S;  /^-crystallin,  on  the  contrary,  17.04^  X  and  1.27^  S.  The  first 
coagulates  at  about  72°  C,  and  the  other  at  03°  C.  Besides  this,  /S-crvstal- 
lin  is  precipitated  from  salt-free  solution  with  greater  difficulty  bv  acetic 
acid  or  carbon  dioxide.     These  globulins  are  not  precipitated  by  an  excess 


'  Zeitschr.  f.  Biologic.  Bd.  31.     A  complete  index  of  literature  may  be  found  here. 
*  Zeitscbr.  f.  physiol.  Chem..  Bd.  18.     This  contain.s  also  the  pertinent  literature. 


368  BRAIN  AND  NERVES. 

ot  NaCl  at  either  the  ordinary  temperature  or  30°  C.    Magnesium  or  sodium 

sulphate   in    substance   precipitates    both    globulins,    on    the   contrary,    at 

30°  C.     These  two  globulins  are  not  equally  divided  in  the  mass  of  the  lens. 

The  quantity  of  «f-crystallin  diminishes  in  the  lens  from  without  inwards; 

/^-crystallin,  on  the  contrary,  from  within  outwards. 

ABechamp'  distinguishes  the  two  following  albuminous  bodies  in  the  watery 
extract  of  the  crystalline  lens:  p7iacozi/mase, which  coagulates  at  +  55°  C.  and  contains 
a  diastatic  enzyme,  and  has  a  specitic  rotatory  power  of  {cx)j  =  —  41°,  and  the  crystal- 
humin,  with  a  specific  rotatory  power  of  {a)j  =  —  80°. 3.  From  the  residue  of  the  lens, 
which  was  insoluble  in  water,  Bechamp  extracted,  by  means  of  hydrochloric  acid,  an 
albuminous  body  having  a  specific  rotatory  power  of  {a)j  =  —  80°. 2  which  is  called 
crystaliibrin. 

The  lens  does  not  seem  to  contain  any  proteid  bodies  which  coagulate 
spontaneously  like  fibrinogen.  That  cloudiness  which  appears  after  death 
depends,  according  to  Kuhne,  upon  the  unequal  changing  of  the  concen- 
tration of  the  contents  of  the  lens-tubes.  This  change  is  produced  by  the 
altered  ratio  of  diffusion.  A  cloudiness  of  the  lens  may  also  be  produced  in 
life  by  a  rapid  removal  of  water,  as,  for  example,  when  a  frog  is  plunged 
into  a  salt  or  sugar  solution  (Kuistde").  The  appearance  of  cloudiness  in 
diabetes  has  been  attributed  by  some  to  the  removal  of  water.  The  views 
on  this  subject  are,  however,  contradictory. 

Thy  average  results  of  four  analyses  made  by  LAPTSCHiisrsKY '  of  the 
lens  of  oxen  are  here  given,  calculated  in  parts  per  1000: 

Proteids    349.3 

Lecithin 2.3 

CliolesLerin 2.2 

Fat 2.9 

Soluble  salts 5.3 

Insoluble  salts , 2.3 

In  cataract  the  amount  of  proteids  is  diminished  and  the  amount  of 
cholesterin  increased. 

The  quantity  of  the  different  proteids  in  the  fresh  moist  lens  of  oxen  is 
as  follows,  according  to  Mornek  * : 

Albumoid  (lens-fibres) 170  p.  m. 

/?-crystalliii 110     " 

a-crystailin 68     " 

Albumin 2     " 

The  corneal  tissue  has  been  previously  treated  of  (page  320).  The 
sclerotic  has  not  been  closely  investigated,  and  the  choroid  coat  is  chiefly 
of  interest  because  of  the  coloring  matter,  melanin,  it  contains  (see  Chap. 
XVI). 

Tea  IIS  consist  of  a  water-clear,  alkaline  fluid  of  a  saltish  taste.     Accord- 

'  Compt.  rend.,  Tome  90. 

'  Kiihiie,  Lehrbuch  d.  physiol.  Chem. ,  S.  405  ;  Kunde,  cited  from  Klihne. 

'Plluger's  Arch.,  Bd.  13. 

♦  L.  c. 


FLUIDS   OF  TlIK  INNKli   EAR.  369 

itig  to  the  analyses  of  Lliuji  '  they  contuiu  982  p.  ni.  water,  18  p.  in.  solids, 
with  5  p.  ni.  albumin  and  i;i  p.  m.  NaCl. 

The  Fluids  of  the  Inner  Ear. 

The  perilymph  and  endolymph  are  alkaline  fluids  which,  besides  salts, 
contain — in  the  same  amounts  as  in  transudations — traces  of  p7'oteid,  and  in 
certain  animals  (codfish)  also  viucin.  The  quantity  of  mucin  is  greater  in 
the  perilympli  than  in  the  endolymph. 

Otoliths  contain  745-795  p,  m.  inorganic  substance,  which  consists 
chiefly  of  crystallized  calcium  carbonate.  The  organic  substance  is  very 
like  mucin. 

'  Cited  from  Gorup-Besanez,  Lehrb.  d.  physiol.  Cbem.,  4.  Aufl.,  S.  401. 


CHAPTER   XIII. 
ORGANS  OP   GENERATION. 

(a)  Male  Generative  Secretions. 

l.Hi!]  testis  have  been  little  investigated  chemically.  We  find  in  the 
testis  of  animals  proteid  bodies  of  different  kinds,  sercdbumin,  alkali  albu- 
minate (?),  and  an  albaminous  body  related  to  Rovidas'  hyaline  suhstancBy 
also  leucin,  tyrosiii,  creatin,  xanthin  bodies,  cholesteriti,  lecithin,  inosit,  and 
fat.  In  regard  to  the  occurrence  of  glycogen  the  statements  are  somewhat 
contradictory.  Dareste'  found  in  the  testis  of  birds  starch-like  granules, 
which  were  colored  blue  with  difficulty  by  iodine. 

The  semen  as  ejected  is  a  white  or  whitish-yellow,  viscous,  sticky  fluid 
of  a  milky  appearance,  with  whitish,  non-transparent  lumps.  The  milky 
appearance  is  due  to  spermatozoa.  Semen  is  heavier  than  water,  contains 
proteids,  has  a  neutral  or  faintly  alkaline  reaction  and  a  peculiar  specific 
odor.  Soon  after  ejection  semen  becomes  gelatinous,  as  if  it  were  coagn- 
lated,  but  afterwards  becomes  more  fluid.  When  dihited  with  water  white 
flakes  or  shreds  separate  (Henle's  j^Zrm).  According  to  the  analyses  of 
Vauquelin  ^  human  semen  contains  900  p.  m.  water  and  100  p.  m.  solids, 
with  GO  p.  m.  organic  and  40  p.  m.  inorganic  substance,  of  which  30  p.  m. 
is  calcium  phosphate.  Among  the  albuminous  bodies  Posj^er  '  claims  that 
alburnose    (propeptone)  occurs  even  in  the  absence  of  the  spermato?;oa. 

The  semen  in  the  vas  deferens  differs  chiefly  from  the  ejected  semen  in 
that  it  is  without  the  peculiar  odor.  This  last  depends  on  the  admixture 
with  the  secretion  of  the  prostate.  This  secretion,  according  to  Iversen,* 
has  a  milky  appearance  and  ordinarily  an  alkaline  reaction,  very  rarely  a 
neutral  one,  and  contains  small  amounts  of  proteids  and  mineral  bodies, 
especially  NaCl.  Besides  these  it  contains  a  crystalline  combination  of 
phosphoric  acid  with  a  base,  C^HjlS".  Tliis  combination  has  been  called 
Bottcher's  spermin  crystals,  and  it  is  claimed  that  tiie  si^ecific  odor  of  the 
semen  is  due  to  a  partial  decomposition  of  these  crystals. 

'  Compt.  rend.,  Tome  74. 

«  Cited  from  Lehmann's  Lehrb.  d,  physiol.  Chein.  (Leipzig,  1853),  Bd.  2,  S.  303. 
»  Berlin,  klin.  Wocbenschr.,  1888,  No.  21,  and  Centralbl.  f.  d.  med.  Wissensch.,  1890^ 
S.  497. 

*  Nord.  med.  Ark.,  Bd.  6  ;  also  Maly's  Jahresber.,  Bd.  4,  S.  358. 

370 


SPERMATOZOA.  371 

The  crystals  which  appear  on  slowly  evaporating  the  semen,  and  whiclx 
are  also  observed  in  anatomical  preparations  kept  in  alcoliol  and  in  desiccated 
egg-albumin,  are  identical,  according  to  Schreinek,  with  Charcot's 
crystals  found  in  tlie  blood,  and  in  the  lymphatic  glands  in  lenca?niia,  but 
this  has  not  been  proved.  They  are,  according  to  Schrkiner,'  a  combina- 
tion of  phosphoric  acid  with  a  base,  sj)ernimy  C,II,N,  which  he  discovered. 

Spermin.  The  views  in  regard  to  the  nature  of  tliis  base  are  not  unanimous.  Accord- 
ing to  the  investigations  of  LADENBUUd  and  Aijkl,  it  is  not  improbable  that  spermin  is 
identical  with  ethyleuimin  ;  but  tliis  identity  is  disputed  by  Ma.ieut  and  A.  Schmidt, 
and  also  by  Poehl.  The  compound  of  spermin  with  phosphoric  acid — lioTiciiER's 
spermin  crystals — is  insoluble  in  alcohol,  ctiicr,  and  chloroform,  soluble  with  difficulty 
in  cold  water,  but  more  readil}'  in  hot  water,  and  easily  soluble  in  dilute  acids  or  alka- 
lies, also  alkali  carbonates  and  ammonia.  The  base  is  precipitated  by  tannic  acid, 
mercuric  chloride,  gold  chloride,  platinic  chloride,  potassium-bismuthic  iodide,  and 
phospho-tuugstic  acid.  Spermin  has  a  tonic  action,  and  according  to  Poehl'  it  has  & 
marked  action  on  the  oxidation  processes  of  the  animal  body.' 

The  spermatozoa  show  a  great  resistance  to  chemical  reagents  in  general. 
They  do  not  dissolve  completely  in  concentrated  sulphuric  acid,  nitric  acid, 
acetic  acid,  nor  in  boiling-hot  soda  solutions.  They  are  soluble  in  a  boiling- 
hot  caustic-potash  solution.  They  resist  putrefaction,  and  after  drying 
they  may  be  obtained  again  in  their  original  form  by  moistening  them  with 
a  1^  common-salt  solution.  By  careful  heating  and  burning  to  an  ash  the 
shape  of  the  spermatozoa  may  be  seen  in  the  ash.  The  quantity  of  ash  is 
about  50  p.  m.  and  consists  mainly  (f )  of  potassium  phosphate. 

The  spermatozoa  show  well-known  movements,  but  the  cause  of  this  is 
not  known.  This  movement  may  continue  for  a  very  long  time,  as  under 
some  conditions  it  may  be  observed  for  several  days  in  the  body  after  death, 
and  in  the  secretion  of  the  uterus  longer  than  a  week.  Acid  liquids  stop 
these  movements  immediately;  they  are  also  destroyed  by  strong  alkalies, 
especially  ammoniacal  liquids,  also  by  distilled  water,  alcohol,  ether,  etc. 
The  movements  continue  for  a  longer  time  in  faintly  alkaline  liquids, 
especially  in  alkaline  animal  secretions,  and  also  in  properly  diluted  neutral- 
salt  solutions. 

Spermatozoa  are  nucleus  formations  and  hence  are  rich  in  nucleic  acid, 
which  exists  in  the  heads.  The  tails  contain  proteid  and  are  besides  this  rich 
in  lecithin,  cholesterin,  and  fat,  which  bodies  only  occur  to  a  small  extent 
(if  at  all)  in  the  heads.  The  tails  seem  by  their  composition  to  be  closely 
allied  to  the  non-mednllated  nerves  or  the  axis-cylinders.  In  the  various 
kinds  of  animals  investigated,  the  head  contains  nucleic  acid,  and  this  is 

'-  Schreiner,  Annal.  de  Chem.  u.  Pharm.,  Bd.  194.  See  also  Tb.  Cohn,  Deutsch. 
Arch.  f.  klin.  Med.,  Bd.  54. 

'  Ladenburg  and  Abel,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  21  ;  ^lajert  and  A. 
Schmidt,  ibid.,  Bd.  24  ;  Poehl,  Compt.  rend.,  Tome  115,  Berlin,  klin.  Wochenschr.,  1891 
and  1893,  Deutsch.  med.  Wochenschr..  1893  and  1895.  and  Zeitschr.  f.  klin.  :Med.,  1894. 

» In  regard  to  the  so-called  Florence's  semen  renction  see  Posuer,  Berlin,  klin. 
Wochenschr.,  1897,  and  Richter,  Wien.  klin.  Wochenschr.,  1897. 


S72  ORGANS  OF  GENERATION. 

united  witli  protamin  (or  salmin  and  starin)  in  certain  fishes  (salmon, 
herring,  and  stargeon).  In  other  animals,  such  as  the  carp,  ball,  and  boar, 
proteid-like  substances  occur  with  the  nucleic  acid,  bat  no  protamin.  The 
same  is  trae  for  the  sea-urchin,  arbacia,  whose  spermatozoa  contain  nacleic 
^cid  in  combination  with  a  histon-like  body,  arbacin. 

Our  knowledge  of  the  chemical  composition  of  spermatozoa  has  been 
greatly  enhanced  by  the  important  investigations  of  Miescher  '  on  salmon 
roe.  The  intermediate  fluid  of  the  spermatozoa  of  Rhine  salmon  is  a  dilate 
salt  solution  containing  1.3-1.9  p.  m.  organic  bodies  and  6,5-7.5  p.  m. 
inorganic.  The  last  consist  chiefly  of  sodium  chloride  and  carbonate,  besides 
some  potassium  chloride  and  sulphate.  It  only  contains  traces  of  proteid, 
b»ut  no  peptone.  The  tails  consist  of  419  p.  m.  proteid,  318.3  p.  m.  lecithin, 
and  262.7  p.  m.  cholesterin  and  fat.  The  heads  extracted  with  alcohol- 
ether  contain  on  an  average  960  p.  m.  nucleic  acid  protamin,  which  never- 
theless is  not  uniform,  but  is  so  divided  that  the  outer  layers  consist  of  basic 
nucleic  acid  protamin,  while  the  inner  layers,  on  the  contrary,  consist  of  acid 
nucleic  acid  protamin.  Besides  the  nucleic  acid  protamin  we  have  in  the 
heads,  although  to  a  very  slight  extent,  unknown  organic  substances.  The 
unripe  salmon  spermatozoa,  while  developing,  also  contain  nucleic  acid,  but 
no  protamin,  with  a  proteid  substance,  "  alhuminose,''''  which  probably  is  a 
.■step  in  the  formation  of  protamin. 

As  in  the  salmon  so  in  the  herring  the  spermatozoa  heads  contain  nucleic 
^cid  protamin,  according  to  Kossel  and  Mathews,'  and  they  are  free  from 
{proteid.  Mathews,  who  investigated  the  spermatozoa  of  the  sea-urchin, 
has  substantiated  Miescher's  statement  that  protamin  does  not  exist  in  the 
bull-spermatozoa.  According  to  him  boar-spermatozoa  are  also  free  from 
protamin. 

Spermatin  is  a  name  which  haa  been  given  to  a  constituent  similar  to  alkali  albumin- 
ate, but  it  h;is  not  been  closely  studied. 

Prostatic  concrements  are  of  two  kinds.  One  is  very  small,  generally  oval  in  shape, 
■with  concentric  layers.  In  younir  but  not  in  older  persons  they  are  colored  blue  by 
iodine  (Iversen^).  The  other  kind  is  larger— sometimes  the  size  of  the  head  of  a  pin, 
and  consisting  chiefly  of  calcium  phosphate  (about  700  p.  m.),  with  only  a  very  small 
^amount  (about  160  p.  m.)  organic  substance. 

(b)  Female  Generative  Organs. 

The  stroma  of  the  ovaries  are  of  little  interest  from  a  physiologico- 
chemical  standpoint,  and  the  most  important  constituent  of  the  ovaries,  the 
Graafian  follicles  with  the  ovum,  have  thus  far  not  been  the  subject  of  a 
careful  chemical  investigation.     The  fluid  in  the  follicles  (of  the  cow)  does 

'  See  Miescher,  "  Die  histochemischeu  und  physiologischeu  Arbeiten  von  Friedrich 
Miescher,  gesammelt  und  herausgegeben  von  seineu  Freunden."    Leipzig,  1897. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  33. 
3  L.  c. 


SEliUUS  AMJ  J'JiOLJFEIlOf.s   CVSTS.  375 

not  contain,  as  lias  been  stated,  the  peculiar  bodies,  paralbumin  or  metalbu- 
min,  which  are  found  in  certain  pathological  ovarial  iluids,  but  seems  to  be  a 
serous  liquid.  The  corpora  hitea  are  colored  yellow  by  an  amorphous  pigs 
ment  called  hiiein.  Besides  this,  another  coloring  matter  sometimes  occur- 
which  is  not  .soluble  in  alkali;  it  is  crystalline,  but  not  identical  with 
bilirubin  or  ha-matoidin;  but  it  may  be  identified  as  a  lutein  by  its  spectro- 
scopic behavior  (Piccolo  and  Likben,  Kijhxe  and  EwaliV). 

The  cysts  often  occurring  in  the  ovaries  are  of  special  pathological 
interest,  and  these  may  have  essentially  different  contents,  depending  upon 
their  variety  and  origin. 

The  serous  cysts  (Hydrops  folliculorum  Graafii),  which  are  formed 
by  a  dilation  of  the  Graafian  follicles,  contain  a  serous  liquid  which  has  a 
specific  gravity  of  1.005-1.022.  A  specific  gravity  of  1.020  is  less  frequent. 
Generally  the  specific  gravity  is  lower,  1.005-1.014,  with  10-40  p.  m.  solids. 
As  far  as  is  known,  the  contents  of  these  cysts  do  not  essentially  differ  from 
other  serous  liquids. 

The  proliferous  cysts  (myxoid  cysts,  colloid  cysts),  which  are 
developed  from  Pfluger's  epithelium-tubes,  may  have  a  contents  of  a  very 
variable  composition. 

We  sometimes  find  in  small  cysts  a  semi-solid,  transparent,  or  somewhat 
cloudy  or  opalescent  mass  which  appears  like  solidified  glue  or  quivering- 
jelly,  and  which  has  been  called  colloid  because  of  its  physical  i)ro})erties.. 
In  other  catrtb  the  cysts  contain  a  thick,  tough  mass  which  can  be  drawn  out 
into  long  threads,  and  as  this  mass  in  the  different  cysts  is  more  or  lesss. 
diluted  with  serous  liquids  their  contents  may  have  a  variable  consistency. 
In  still  other  cases  the  small  cysts  may  also  contain  a  thin,  watery  fluid.. 
The  color  of  the  contents  is  also  variable.  Sometimes  they  are  bluish  white,, 
opalescent,  and  again  they  are  yellow,  yellowieh  brown,  or  yellowish  with  a 
shade  of  green.  They  are  often  colored  more  or  less  chocolate-brown  or 
red-brown,  due  to  the  decomposed  blood-coloring  matters.  The  reaction  is 
alkaline  or  nearly  neutral.  The  specific  graviiy,  which  may  vary  consider-- 
ably,  is  generally  1.015-1. 030,  but  may  occasionally  be  1.005-1.010  or 
1.050-1.055.  The  amount  of  solids  is  very  variable.  In  rare  cases  thejr 
amount  to  only  10-20  p.  m. ;  ordinarily  they  vary  between  50-70-100  p.  m.. 
In  a  few  instances  150-200  p.  m.  solids  have  been  found. 

As  form-elements  we  find  red  and  white  blood-corpvscles,  granular  cells^ 
partly  fat-degenerated  epithelium  and  partly  large  so-called  Glfge's  cor- 
puscles, fine  granular  masses^  epiihelivm-celh^  cholesierin  crystals,  and 
colloicl  corpuscles — large,  circular,  highly  refractive  formations. 

Though  the  contents  of  the  proliferous  cyst  may  have  a  variable  compo- 
sition, sitll  it  may  be  characterized  in   typical  cases  by  its  slimy  or  ropy 

'  See  Chapter  VI,  page  152. 


374  OBGANS  OF  GENERATION. 

consistency ;  by  its  grayish -yellow,  chocolate-brown,  sometimes  whitish-gray 
color;  and  by  its  relatively  high  specific  gravity,  1.015-1.025.  Such  a 
liquid  does  not  ordinarily  show  a  spontaneous  fibrin-coagulation. 

"We  consider  colloid,  metalhumin,  aud  paralbumin  as  characteristic  con- 
stituents of  these  cysts. 

Colloid.  This  name  does  not  designate  any  particular  chemical  sub- 
stance, but  is  given  to  the  contents  of  tumors  with  certain  physical  proper- 
ties similar  to  gelatin  jelly.  Colloid  is  found  as  a  morbid  product  in 
several  organs. 

Colloid  is  a  gelatinous  mass,  insoluble  in  water  and  acetic  acid;  it  is 
dissolved  by  alkalies  and  gives  a  liquid  which  is  not  precipitated  by  acetic 
ficid  or  by  acetic  acid  and  potassium  ferrocyanide.  According  to  Pfanisten"- 
STIEL '  such  a  colloid  is  designated  /J-pseudomucin.  Sometimes  a  colloid  is 
found  which,  when  treated  with  a  very  dilute  alkali,  gives  a  solution  similar 
to  a  mucin  solution.  On  boiling  with  acids  colloid  gives  a  reducing  sub- 
stance. It  is  related  to  mucin,  and  it  is  considered  by  certain  investigators 
as  a  transformed  mucin.  A  colloid  found  by  Wurtz  ^  in  the  lungs  contains 
C  -18.09,  H  7.47,  N  7.00,  and  0  37.44^.  Colloids  of  different  origin  seem 
to  be  of  varying  composition. 

Meiallumin.  This  name  Scherer'  gave  to  a  protein  substance  found 
hy  him  in  an  ovarial  fluid.  The  metalbumin  was  considered  by  Scherer 
to  be  an  albuminous  body,  but  it  belongs  to  the  mucin  group,  and  it  is  for 
"this  reason  cdlledL  pseudomucin  by  Hammarsten.'' 

Pseudomucin.  This  body,  which,  like  mucins,  gives  a  reducing  substance 
when  boiled  with  acids,  is  a  mucoid  of  the  following  composition:  C  49.75, 
H  G.98,  N  10.28,  S  1.25,  0  31.74^  (HammaRsten).  AVith  water  pseudo- 
mucin gives  a  slimy,  ropy  solution,  and  it  is  this  substance  which  gives  the 
fluid  contents  of  the  ovarial  cysts  their  typical  ropy  proj^erty.  Its  solutions 
do  not  coagulate  on  boiling,  but  only  become  milky-opalescent.  Unlike 
mucin  solutions,  pseudomucin  solutions  are  not  precipitated  by  acetic  acid. 
With  alcohol  they  give  a  coarse  flocculent  or  thready  precipitate  which  is 
soluble  even  after  having  been  kept  nnder  water  or  alcohol  for  a  long  time. 

Paralbumin  is  another  substance  discovered  by  Scherer,^  and  which 
occurs  in  ovarial  liquids  and  also  in  ascites  fluids  with  the  simultaneous 
presence  of  ovarial  cysts  and  rupture  of  the  same.  It  is  therefore  only  a 
mixture  of  pseudomucin  with  variable  amounts  of  proteid,  and  the  reactions 
of  paralbumin  are  correspondingly  variable. 

'  Arch.  f.  Gynak.,  Bd.  38. 

*  See  Lebert,  Beitr.  zur  Kenntniss  des  G.'illertkrcbscs,  Viicliow's  Aicli.,  Bd.  4. 
'  Verb.  d.  pbysik.-med.  Gcsellscb.  inWurzbuig,  Bd.  2,  and  Sitzungsber.  der  physik.- 
med.  Gesellsch.  in  Wilrzbnrg  fQr  1864-1865  ;  Wiirzburg  med.  Zeitschr.,  Bd.  7. 
«  Zeitschr.  f.  physiol.  Cbem.,  Bd.  6. 
»L.  c,  Verb.,  etc.,Bd.  2. 


PSEUDOMUCIN.  375 

Mit.iikoff'  lias  isolntcd  nnd  invest igiitod  ji  colloid  from  nn  ovnrial  ryst.  Il  Imd  the 
foUowiiii;  com  posit  ion  :  C  51.76,  117  7(>,  N.  10.7.  W  1  09,  nnd  ()  •..'8.<J9;^.  und  diiren-d 
fniiu  naicin  and  pseudouuicin  by  icducinj;  Fkhmng's  solution  before  boiling  with  acid. 
It  must  bo  reniiu  kod  tliat  pseudomiicin,  on  boiling  siillicienlly  long  with  alkiili,  or  by 
the  nsc  of  a  concentrated  solution  of  caustic  alkali,  also  splits  and  causes  a  reduction. 
This  reduction  is  nevertheless  weak  as  compared  with  that  produced  after  boiling  with 
an  acid.     The  body  isolated  by  Mit.iukofk  is  called  parnnturin. 

The  detection  of  metalbnmin  tiiul  panilbnmiu  is  naturally  connected 
with  the  detection  of  pseitdonincin.  A  typical  ovarial  fluid  containinf^ 
pseudomuciti  is,  as  a  rule,  stiflicieiitly  characterized  by  its  physical  proper- 
ties, and  a  special  ciiemical  investigation  is  only  necessary  in  cases  where  a 
serous  Uuid  contains  very  small  amounts  of  pseudomucin.  We  proceed  in 
the  following  way:  The  proteid  is  removed  by  heating  to  boiling  with  the 
addition  of  acetic  acid;  the  filtrate  is  strongly  concentrated  and  precijiitated 
by  alcohol.  The  precij)itate  is  carefully  washed  with  alcohol,  and  then 
dissolved  in  water.  A  part  of  this  solution  is  digested  with  saliva  at  the 
temperature  of  the  body  and  then  tested  for  glucose  (derived  from  glycogen 
or  dextrin).  If  glycogen  is  present,  it  will  be  converted  into  glucose  by  the 
saliva;  precipitate  again  with  alcohol  and  then  2)roceed  as  in  the  absence  of 
glycogen.  In  this  last-mentioned  case,  first  add  acetic  acid  to  tlie  solution 
of  the  alcohol  jirecipitate  in  water  so  as  to  precipitate  any  existing  mucin. 
The  precipitate  produced  is  filtered,  the  filtrate  treated  with  -i^c  HCi,  and 
warmed  on  the  water-bath  until  the  liquid  is  deep  brown  in  color.  In  the 
presence  of  pseudomucin  this  solution  gives  Trommer\s  test. 

The  other  protein  bodies  wdiich  have  been  found  in  cystic  fluids  are 
serglobiilin  and  seralbumin^  peptone  (/),  niucin,  miicin-peptone  (?).  Fibrin 
occurs  only  in  exceptional  cases.  Tlie  quantity  of  mineral  bodies  on  an 
average  amounts  to  about  10  p.  m.  The  amount  of  extractive  bodies 
{cholesterin  and  iirea)  and  fat  is  ordinarily  2-4  p.  m.  The  remaining  solids, 
which  constitute  the  chief  mass,  are  albuminous  bodies  and  pseudomucin. 

The  intraligamentary,  papillary  cysts  contain  a  yellow,  yellowish-green, 
or  brownish-green  liquid  which  contains  either  no  pseudomucin  or  very 
little.  The  specific  gravity  is  generally  rather  high,  1.032-1.036,  with 
90-100  p.  m.  solids.  The  principal  constituents  are  the  albuminous  bodies 
of  blood-serum. 

The  rare  tubo-ovarial  cysts  contain  as  a  rule  a  watery,  serous  fluid  con- 
taining no  pseudomucin. 

The  parovarial  cysts  or  the  cysts  of  the  ligamp:xta  lata  may  attain  a 
considerable  size.  In  general,  and  when  quite  typical,  the  contents  are 
watery,  mostly  very  pale  yellow-colored,  water-clear  or  only  slightly  opalescent 
liquids.  The  specific  gravity  is  low,  1.002-1.009;  and  the  solids  only 
amount  to  10-20  p.  m.  Pseudomucin  does  not  occur  as  a  typical  constit- 
uent; proteid  is  sometimes  absent,  and  when  it  does  occur  the  quantity  is 
very  small.  The  principal  part  of  the  solids  consists  of  salts  and  extractive 
bodies.  In  exceptional  cases  the  fluid  may  be  rich  in  proteid  and  may  show 
a  higher  specific  gravity. 

•  K.  MitjukofT,  Arch.  f.  Gyniikol.,  Bd.  49. 


376  ORGANS  OF  GENERATION. 

la  regard  to  the  qaantitative  composition  of  the  fluid  from  ovarial  cysts 

we  refer  the  reader  to  the  Avork  of  OERUii.' 

E.  LrowiG  aud  R.  v.  Zeynek'  have  recently  investigated  the  fat  from  dermoid  cysts. 
Besides  a  little  arachidic  acid,  they  found  oleic,  stearic,  palmitic,  and  myristic  acids, 
cetylalcohol,  and  a  cholesterin-like  substance. 

The  Ovum. 

The  small  ova  of  man  and  mammals  cannot,  for  evident  reasons,  be  the 
subject  of  a  searching  chemical  investigation.  Up  to  the  present  time  the 
eggs  of  birds,  amphibians,  and  fishes  have  been  investigated,  but  above  all 
the  hen's  egg.  We  will  here  occupy  ourselves  with  the  constituents  of  this 
last. 

The  Yolk  of  the  Hen's  Egg.  In  the  so-called  white  yolk,  which  forms 
the  yeriii  with  a  process  reaching  to  the  centre  of  the  yolk  {latebra),  and  also 
forms  a  layer  between  the  yolk  and  yolk-membrane,  we  find  proteidy  nuclem, 
lecithin,  audi  potassium  (Liebeemaxk"  ^).  The  occurrence  of  glycogen  is 
doubtful.  The  yolk-membrane  consists  of  an  albumoid  similar  in  certain 
respects  to  keratin  (Liebermaxk). 

The  principal  part  of  the  yolk — the  nutritive  yolk  or  yellow — is  a 
viscous,  non-transparent,  pale-yellow  or  orange-yellow  alkaline  emulsion 
of  a  mild  taste.  The  yolk  contains  vitellm,  lecithin,  cholesteri^i,  fat,  color- 
ing matters,  traces  of  neuridin  (Beieger^),  ghicose  in  very  small  quantities, 
and  mineral  bodies.  The  occurrence  of  cerebrin  and  of  granules  similar  to 
starch  (Dareste  ^)  has  not  been  positively  proved. 

Ovovitellin.  This  body  is  generally  considered  as  a  globulin,  but  it 
resembles  a  nucleoalbumin  more.  The  question  as  to  what  relationship 
other  protein  substances  which,  like  the  aleuron-grains  of  certain  seeds  and 
the  yolk  spherules  of  the  eggs  of  certain  fishes  and  amphibians,  are  related 
to  ovovitellin,  bear  to  this  substance,  is  a  question  which  requires  further 
investigation. 

The  ovovitellin  which  has  been  prepared  from  the  yolk  of  eggs  is  not  a 
pare  albuminous  body,  but  always  contains  lecithin.  Hoppe-Seyler  found 
25^  lecithin  in  vitellin  and  also  some  psendonuclein.  The  lecithin  may  be 
removed  by  boiling  alcohol,  but  the  vitellin  is  changed  thereby,  and  it  is 
therefore  probable  that  the  lecithin  is  chemically  united  with  the  vitellin 
(Hoppe-Seyler").     Bunge'  prepared  a  psendonuclein  by  digesting  the 

'  Kemiske  Studier  over  Ovariecystevcedsker,  etc.  Koebenhavn,  1884.  See  also 
Maly's  Jahresber..  Bd.  14,  S.  4.59. 

^  Zeitschr.  f.  physiol.  Chein.,  Bd.  23. 
»  Pfluger's  Arch.,  Bd.  43. 

*  Uebor  Ptomaine.     Berlin,  1885. 

*  Compt.  rend..  Tome  72. 
•Med.  chem.  Untersuch.,  S.  21G. 
'Zeitschr.  f.  physiol.  Chem.,  Bd.  0. 


THE  OVUM.  877 

yolk  Avith  gastric  juice,  and  this  pseuilomiclein,  according  to  liim,  is  of  great 
importance  in  the  formation  of  the  blood,  and  on  these  grounds  he  called  it 
hcvmatogen.  This  hsematogen — whose  composition  is  as  follows:  C  42.11, 
JI  G.08,  N  14.;;5,  S  0.55,  V  5.10,  Fe  0.29,  and  O  31.05^— seems  to  be  a 
decomposition  product  of  vitellin. 

Vitellin  is  similar  to  the  globulins  in  that  it  is  insoluble  in  water,  but 
on  the  contrary  soluble  in  dilute  neutral-salt  solutions  (although  the  solution 
is  not  quite  transparent).  It  is  also  soluble  in  hydrochloric  acid  of  1  p.  )ii, 
and  in  very  dilute  solutions  of  alkalies  or  alkali  carbonates.  It  is  precipi- 
tated from  its  salt  solution  by  diluting  with  water,  and  when  allowed  to 
stand  some  time  in  contact  with  water  the  Yitellin  is  gradually  changed, 
forming  a  substance  more  like  the  albuminates.  The  coagulation  tempera- 
ture for  the  solution  containing  salt  (NaCl)  lies  between  -|-  70°  and  75°  C.  • 
or,  when  heated  very  rapidly,  at  about  -f-  80°  C.  Vitellin  differs  from  the 
globulins  in  yielding  pseudonuclein  by  pepsin  digestion.  It  is  not  always 
comi>letely  precipitated  by  NaCl  in  substance. 

The  chief  points  in  the  preparation  of  ovovitellin  are  as  follows :  The 
yolk  is  thoroughly  agitated  with  ether;  the  residue  is  dissolved  in  a  10^ 
common-salt  solution,  fdtered,  and  the  vitellin  precipitated  by  adding  an 
abundance  of  water.  The  vitellin  is  now  ])urified  by  repeatedly  redissolving 
in  dilute  common-salt  solutions  and  precipitating  with  water. 

Ichthulin,  wliicli  occurs  in  the  eggs  of  the  carp  aud  otlier  fishes,  is,  according  to 
KossKi.  and  Wai/i'ek,'  an  aniorplious  modification  of  tlie  crystalline  body  iclithidin, 
wliicli  occurs  in  the  eggs  of  the  carp.  Ichtliulin  is  precipitated  on  diluting  with  water. 
It  used  to  be  considered  as  a  vitellin.  According  to  Wai/fku  it  yields  a  pseudonuclein 
on  peptic  digestion;  and  this  pseudonuclein  gives  a  reducing  carbohydrate  on  boiling 
Aviljj  sulpluiric  acid.  Ichtliulin  has  tlie  followinc:  composition:  C  53.42  ;  117.63; 
N  15.G3  ;  O  22.19  ;  S0.41  ,  P  0.43.     It  also  contains  "iron. 

The  yolk  also  contains,  besides  vitellin,  alkali-albuminate  and  albumin. 

The  fat  of  the  yolk  of  the  egg  is,  according  to  Liebermaxn,  a  mixture 
of  a  solid  and  a  liquid  fat.  The  solid  fat  consists  chiefly  of  tripalmitin  with 
some  stearin.  On  the  saponification  of  the  egg-oil  Liebekmann  obtained 
40^  oleic  acid,  38.04^  palmitic  acid,  and  15.21^  stearic  acid.  The  fat  of 
the  yolk  of  the  Qgg  contains  less  carbon  than  other  fats,  which  may  depend 
on  the  presence  of  monoglycerides  and  diglycerides,  or  on  a  quantity  of 
fatty  acid  deficient  in  carbon  (Liehermann). 

Lutein.  Yellow  or  orange-red  amorphous  coloring  matters  occur  in  the 
yellow  of  the  Ggg  and  in  several  other  places  in  the  animal  organism;  for 
instance,  in  the  blood-serum  and  serous  fluids,  fatty  tisues,  milk-fat,  corpora 
Jiitea,  and  in  the  fat-globules  of  the  retina.  These  coloring  matters,  which 
also  occur  in  the  vegetable  kingdom  (Tuudichum  "),  have  been  called  hUehies 
or  lipochromes. 


'  Zeilschr  f.  physiol.  Chem.,  Bd.  15. 

«  Centralbl.  f.  d.  med.  Wissensch.,  1869,  No.  1. 


378  OBOANS  OF  GENERATION. 

The  luteins,  which  among  themselves  show  somewhat  different  proper- 
ties, are  all  soluble  in  alcohol,  ether,  and  chloroform.  They  differ  from  the 
bile-pigment,  bilirubin,  in  that  they  are  not  separated  from  their  solution 
in  chloroform  by  water  containing  alkali,  and  also  in  that  they  do  not  give 
the  characteristic  play  of  colors  with  nitric  acid  containing  a  little  nitrous 
acid,  but  give  a  transient  blue  color,  and  lastly  they  give  an  absorption- 
spectrum  of  ordinarily  two  bands,  of  which  one  covers  the  line  F,  and  the 
other  lies  between  the  lines  i^and  G.  The  luteines  withstand  the  action 
of  alkalies  so  that  they  are  not  changed  when  we  remove  the  fats  present  by 
means  of  saponification. 

Lutein  has  uot  been  prepared  pure.  Maly'  has  found  two  pigments  free  from  iron 
in  the  eggs  of  a  water-spider  {maja  squinado) — one  a  red  {vitellurubin)  and  the  other  a 
yellow  pigment  {vUellolutein).  Both  of  these  pigments  are  colored  blue  by  nitric  acid 
containing  nitrous  acid,  and  beautifully  green  by  concentrated  sulphuric  acid.  The 
absorption-bauds,  especially  of  the  vitellolutein,  correspond  very  nearly  with  those  of 
ovoluteiu. 

The  mineral  bodies  of  the  yolk  of  the  egg  consist,  according  to  Poleck,* 
of  51.2-65.7  parts  soda,  89.3-80.5  potash,  122.1-132.8  lime,  20.7-21.1 
magnesia,  14.5-11.90  iron  oxide,  638.1-667.0  phosphoric  acid,  and  5.5-14.0 
parts  silicic  acid  in  1000  parts  of  the  ash.  We  find  phosphoric  acid  and 
lime  thy  most  abundant,  and  then  potash,  which  is  somewhat  greater  in 
quantity  than  the  soda.  These  results  are  not,  however,  quite  correct,  first, 
because  no  dissolved  phosphate  occurs  in  the  yolk  (Liebermann"),  and 
secondly,  in  burning,  phosphoric  and  sulphuric  acids  are  produced  and  these 
drive  away  the  chlorine,  which  is  not  accounted  for  in  the  j)receding 
analyses. 

The  yolk  of  the  hen's  egg  weighs  about  12-18  grms.  The  quantity  of 
■water  and  solids  amounts,  according  to  Parkes,'  to  471.9  p.  m.  and  528.1 
p.  m.  respectively.  Among  the  solids  he  found  156.3  p.  m.  proteid,  3.53 
p.  m.  soluble  and  6.12  p.  m.  insoluble  salts.  The  quantity  of  fat,  according 
to  Parkes,  is  228.4  p.  m.,  the  lecithin,  calculated  from  the  amount  of 
phosphorns  in  the  organic  substance  in  the  alcohol-ether  extract,  was  107.2 
p.  m.,  and  the  cholesterin  17.5  p.  m. 

The  white  of  the  egg  is  a  faint-yellowish  albuminous  fluid  enclosed  in  a 
framework  of  thin  membranes;  and  this  fluid  is  in  itself  very  liquid,  but 
seems  viscous  because  of  the  presence  of  these  fine  membranes.  That  sub- 
stance which  forms  the  membranes,  and  of  which  the  chalaza  consists,  seems 
to  be  a  body  nearly  related  to  horn  substances  (Liebermanx). 

The  white  of  the  egg  has  a  specific  gravity  of  1.045  and  always  has  an 
alkaline  reaction.  It  contains  850-880  ]).  m.  water,  100-130  p.  m.  proteid 
bodies,  and  7  p.  m.  salts.     Among  the  extractive  bodies  Lehmakn"  found  a 

'  Monatsbefte  f.  Chem.,  Bd.  2. 

'  Cited  from  Gorup-Besanez,  Lehrbuch  d.  physiol.  Chem.,  4.  Auil.,  8.  740. 

»  Hoppe-Seyler,  Med.  chem.  Untersuc;h.,  Ileft  2,  8.  209. 


OVALBUMIN.  379 

fermentable  varietij  of  sugar  wliich  amounted  to  o  p.  m.  or,  according  to 

Meissxek,  80  p.  m.  of  the  solids.'     Besides  these,  we  tind  in  the  white  of 

the  egg  traces  of  fats,  soaps,  lecithin,  and  cholesterin. 

Tlie  white  of  the  cirg  during;  incubiitiou  becoiiu's  tninsparcnt  on  boiling  and  acts  in 
many  respects  like  alkali-ulbuininate.    This  albumin  TAUcnANOFF'  called  "  tntalhumin." 

The  albuminous  bodies  of  the  white  of  the  egg  belong  partly  to  the 
globulin  and  partly  to  the  albumin  gronp.  Besides  these,  tiie  white  of  the 
egg  contains  a  mucoid  substance.  Eiciiholz'  has  described  a  substance 
belonging  to  the  mucin  group,  called  ovomucin,  which  occurs  in  the  white 
of  the  egg  and  which  is  precipitated  from  the  same  on  diluting  with  4  vols, 
water.  It  may  be  purified  by  dissolving  in  soda  solution  and  precipitating 
with  acetic  acid. 

The  ovoglohuJin  is,  according  to  Dillxer,*  closely  related  to  serglobnlin. 
On  diluting  the  white  of  the  egg  with  water  it  parti}'  separates.  It  is  also 
precipitated  by  magnesium  sulphate.  The  quantity  of  globulins  in  the 
white  of  the  egg  is  on  an  average  0.67  p.  m.,  or  about  67  p.  m.  of  the  total 
proteids.  According  to  Corix  and  Berard,^  we  have  two  globulins  in  the 
white  of  the  egg.^  one  coagulating  at  +  57.5°  C,  and  the  other  at  -f  67°  C. 

Ovalbumin,  or  the  albumin  of  the  white  of  the  egg.  Ovalbumin  was 
first  obtained  in  a  crystalline  form  by  IIokmeister,  by  allowing  its  solution 
in  a  half-saturated  ammonium-sulphate  solution  to  evaporate  very  slowly. 
This  crystalline  ovalbumin  is  later  further  studied  by  Gabriel,  Boxdzyxski 
and  Zo.TA,  and  the  two  last-mentioned  investigators  were  able,  by  fractional 
crystallization,  to  show  that  ovalbumin  was  probably  a  mixture  of  several 
albumins  of  about  the  same  elementary  composition  but  with  somewhat 
different  coagulation-temperature,  solubility,  and  specific  rotation.  In  the 
main  these  results  are  in  accord  with  the  views  of  many  other  investigators, 
such  as  Gautier,  Bechamp,  Corix  and  Berard,'  on  the  occurrence  of 
several  albumins,  but  in  details  they  do  not  agree  very  well.  According  to 
Gautier  and  Bechamp  ovalbumin  is  a  mixture  of  two  albumins  with  the 
coagulation-temperature  of  00-63°  and  71-74°  C.  respectively,  while 
according  to  Corix  and  Berard  it  is  a  mixture  of  three  albumins  with  the 
coagulation-temperature  of  67,  72,  and  82°  C,  respectively.  According  to 
Bo-VDZYXSKi  and  Zo.ta  the  portion  which  dissolves  with  difficulty  coagulates 
at  04.5°,  while  the  readily  soluble  portion  coagulates  at  55.5-56°  C.     The 

>  Cited  from  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  739. 

'  PflQger's  Arch..  Bdd.  31,  33,  and  39. 

» .Journ.  of  Physiol..  Vol.  23. 

*  Upsala  Lakarefs.  FOrh.,  Bd.  20  ;  also  Maly's  Jahresber..  Bd.  15,  S.  31. 

'  Travaux  du  laboratoire  de  I'Universite  de  Lifge,  Tome  2  ;  also  Maly's  Jahresber., 
Bd.  18,  S.  13. 

«  Hofmeister,  Zeitschr.  f.  physiol.  Chem..  Bdd.  14,  16,  and  24;  Gabriel,  ibul.,  Bd. 
15;  Boudzynski  and  Zoja,  ibid.,  Bd.  19  ;  Gautier,  Bull.  soc.  cbim.,  Tome  14;  Bechamp, 
^■bid..  Tome  21;  Coriu  aod  Berard,  1  c. 


380  ORGANS  OF  generation: 

elementary  composition  of  ovalbumin  lias  not  been  positively  established, 
BoxDZYXSKi  and  Zoja  found  C  52.07-52.44,  H  G. 95-7.26,  N  15.11-15.58, 
and  S  l.Gl-1.70,'^  for  four  different  fractions,  which  agree  well  with  the 
results  of  Hammaestex,  namely,  C  52.25,  n  6.90,  X  15.26,  S  1.67-1.93^. 
HoFMETSTER,  ou  the  Contrary,  has  never  observed  the  occurrence  of  several 
crystalline  albumins  with  different  solubilities,  aud  he  is  of  the  view  that  the 
crystalline  ovalbumin  prepared  by  Boxdzyxski  and  Zoja  was  not  quite 
pure.  Corresponding  to  this  he  has  found  a  lower  amount  of  sulphur, 
average  1.18,';^,  for  crystalline  ovalbumin.  The  crystalline  ovalbumin 
analyzed  by  Hofmeister,'  which  had  the  composition  C  53.28,  H  7.26, 
X  15.0,  S  1.18,  and  0  23.38,  seems,  however,  to  be  a  glycoproteid,  because 
it  readily  splits  off  a  carbohydrate  group  by  acids.  According  to  Hof- 
meister's  calculation  the  quantity  of  carbohydrate  is  15^.  Paxormow* 
has  prepared  a  crystalline  ovalbumin  which  showed  a  specific  rotatory  power 
of  oi{J))  =  23.6°  after  five  recrystallizations.  Other  investigators  have 
arrived  at  different  figures.  Boxdzyxski  and  Zoja  found  25.8-26.2°, 
29.16°,  34.18°,  and  42.54°  for  various  fractions.  Ovalbumin  has  the 
properties  of  the  albumins  in  general,  but  differs  from  seralbumin  in  the 
following:  Its  specific  rotation  is  lower.  It  is  quickly  rendered  insoluble 
by  alcoh0l.  It  is  precipitated  by  a  sufficient  quantity  of  hydrochloric  acid, 
but  dissolves  with  greater  difficulty  than  seralbumin  in  an  excess  of  the 
acid.  Ovalbumin  in  solution,  when  introduced  into  the  blooi-circulation, 
pases  into  the  urine,  which  is  not  the  case  with  seralbumin. 

Ovalbumin,  or,  more  correctly,  the  mixture  of  albumins,  may  be 
obtained,  according  to  Starke,"  by  precipitating  the  globulins  by  MgSO^ 
at  20°  C.  and  saturating  the  filtrate  with  Na^SO^  at  the  same  temperature. 
The  ovalbumin  which  separates  is  filtered,  pressed,  dissolved  in  water,  and 
freed  from  salts  by  dialysis.  The  dialyzed  solution  is  then  evaporated  in  a 
vacuum  or  at  40-50°  C.  It'  precipitated  with  alcohol,  albumin  becomes 
quickly  insoluble. 

To  prepare  crystallized  ovalbumin  mix  the  white  of  egg,  previously 
beaten  and  separated  from  the  foam,  with  an  equal  volume  of  a  saturated 
solution  of  ammonium  sulphate,  filter  off'  the  globulin,  and  allow  the  filtrate 
to  evaporate  slowly  in  not  too  thin  layers  at  the  temperature  of  the  room. 
The  mass,  which  separates  after  a  time,  is  dissolved  in  water,  treated  with 
ammonium  sulphate  solution  until  a  cloudiness  commences,  and  then 
allowed  to  stand.  After  repeated  recrystallizations  the  mass  is  treated  either 
with  alcohol,  which  makes  the  crystals  insoluble,  or  they  are  dissolved  in 
water  and  purified  by  dialysis.  The  albumin  does  not  crystallize  from  this 
solution  on  spontaneous  evaporation.  (See  also  page  131,  Hopkixs  and 
PiXKUs'  method.) 

Ovomucoid.     This  substance,  first  observed  by  Neumeister  and  consid- 


>  Hofnieister,  Zeitscbr.  f.  physiol.  Chem.,  Bd.  24,  S.  166. 
»  See  Maly's  .Jahresber.,  Bd.  26,  S.  15. 
»  See  Muly's  Juhrcsber.,  Bd.  11,  S.  17. 


OVOMUCOID.  381 

ered  by  him  as  a  psendo-peptone  and  tlien  later  studied  by  Salkowski,  is, 
according  to  C.  Tii.  Moknkk,'  a  mucoid  with  12.05;^  nitrogen  and  2.20^ 
sulphur.  On  boiling  with  dilate  mineral  acids  it  yields  a  reducing  sub- 
stance. Ovomucoid  exists  to  a  great  extent  in  hens'  eggs,  the  solids  of 
which,  in  raund  numbers,  contain  iOfc, 

A  solution  of  ovomucoid  is  not  precipitated  by  mineral  acids  nor  by 
organic  acids,  with  the  exception  of  phosphotangstic  acid  and  tannic  aciu. 
It  is  not  precipitated  by  metallic  salts,  but  basic  lead  acetate  and  ammonia 
give  a  precipitate.  Ovomucid  is  precipitated  by  alcohol,  but  sodium 
chloride,  sodium  sulphate,  and  magnesium  sulphate  give  no  precipitates 
either  at  the  ordinary  temperature  nor  when  added  to  saturation  at  30"  C. 
Its  solutions  are  not  precipitated  by  an  equal  volume  of  a  saturated  solution 
of  ammonium  sulphate,  but  are  precipitated  on  adding  more  salt  thereto. 
The  substance  is  not  precipitated  on  boiling,  but  the  part  wliich  has  become 
insoluble  in  cold  water  and  then  dried  is  precipitated  when  dissolved  in 
boiling  water.  Zanetti'  has  prepared  a  glucosamin  on  splitting  ovomucoid 
with  concentrated  hydrochloric  acid.  Seemaxx  has  also  recently  prepared 
&  glucosamin  from  ovomucoid  (and  as  it  seems  also  from  ovalbumin). 

Ovomucoid  may  be  prepared  by  removing  all  the  proteids  by  boiling  with 
the  addition  of  acetic  acid,  and  then  concentrating  the  filtrate  and  precipi- 
tating with  alcohol.  The  substance  is  purified  by  repeated  solution  in  water 
and  precipitating  with  alcohol. 

The  mineral  bodies  of  the  white  of  the  eg^  have  been  analyzed  bv 
PoLECK  and  Weber.'  They  found  in  1000  parts  of  the  ash:  276. 6-284.5 
grms.  potash,  235.6-329.3  soda,  17.4-20  lime,  16-31.7  magnesia,  4.4-5.5 
iron  oxide,  238.4-285.6  chlorine,  31.6-48.3  phosphoric  acid  (P,OJ, 
13.2-26.3  sulphuric  acid,  2.8-20.4  silicic  acid,  and  96.7-116  grms.  carbon 
dioxide.  Traces  of  fluorine  have  also  been  found  (Xickles  *).  The  ash  of 
the  white  of  the  Qgg  contains,  as  compared  with  the  yolk,  a  greater  amount 
of  chlorine  and  alkalies,  and  a  smaller  amount  of  lime,  phosphoric  acid,  and 
iron. 

The  Shell-membrane  and  the  Egg-shell.  The  shell-membrane  consists, 
as  above  stated  (page  51),  of  a  keratin  substance.  The  shell  contains  very 
little  organic  substance,  36-65  p.  m.  The  chief  mass,  more  than  900 
p.  m.,  consists  of  calcium  carbonate;  besides  this  there  are  very  small 
amounts  of  magnesium  carbonate  and  earthy  phosphates. 

>  R  Neumeister,  Zeitschr.  f.  Biologie,  Bd.  27,  S.  369  ;  Salkowski,  Centralbl.  f.  d. 
med.  Wisseusch.,  1893,  S.  513  aud  706  :  C.  Mbrncr.  Zeitschr.  f.  pbysiol.  Chem.,  I'd.  18. 

'  See  Chem.  Ceutralbl.,  1898,  Bd.  1,  S.  624;  Seeiiiaun,  Archiv  f.  Verdauuugskrank- 
heit  von  Boas,  1898,  Bd.  4. 

*  Cited  from  Iloppe-.Seyler,  Physiol.  Chem.,  S.  778. 

*  Compt.  rend.,  Tome  43. 


382  ORGANS  OF  GENERATION. 

The  diverse  coloring  of  birds'  eggs  is  due  to  several  different  coloring  matters. 
Among  these  we  find  a  red  or  reddish-brown  pigment  called  "  oorodein"  by  Sorby,* 
which  is  perhaps  identical  with  Lsematopoiphyrin.  The  green  or  blue  coloring  matter, 
Sorby's  oocyan,  seems,  according  to  Liebermaxn,^  and  Krukenberg^  to  be  partly 
biliverdin  and  partly  a  blue  derivative  of  the  hile-pigments. 

The  eggs  of  birds  have  a  space  at  their  blunt  end  filled  with  gas;  this 
gas  contains  on  an  average  18.0-19.9^  oxygen  (Hufxer*). 

The  weight  of  a  hen's  egg  varies  between  40-60  grammes  and  may 
sometimes  weigh  TO  grms.  The  shell  and  shell-membrane  together,  when 
carefally  cleaned,  bnt  still  in  the  moist  state,  weigh  5-8  grms.  The  yolk 
weighs  12-18  and  the  white  23-34  grms.,  or  about  double. 

The  white  of  the  egg  of  cartilaginous  and  bony  fishes  contains  only  traces  of  true 
albumin,  and  the  cover  of  the  frog's  egg  consists',  according  to  Giacosa,'  of  mucin. 
The  crystalline  formations  (yolk-spherules  or  dotterpldttchen)  which  have  been  observed  ia 
the  egg  of  the  tortoise,  frog,  ray,  shsirk,  and  other  fishes,  and  which  are  described  by 
Valexcienxes  and  Fremy^' under  the  names  emydin,  ichthin,  ichlJiidln,  and  ichthidin, 
seem,  as  above  stated  in  connection  with  ichthulin,  to  consist  chiefly  of  phosphoglyco- 
proteids.  The  egg  of  the  river-crab  and  the  lobster  contain  the  same  pigment  as  the 
shell  of  the  animal.  This  pigment,  called  cyanocrystallia,  becomes  red  on  boiling  in 
water. 

In  fossil  eggs  (of  aptenodytes,  pelecakus,  and  hall^us)  in  old  guano  deposits,  a 
yellowish-white,  silky,  laminated  combiratiou  has  been  found  which  is  called  giianovuUt, 
(NHJ2SO4  +  2KqS04^  3KHSO4  + 4H2O,  and  which  is  easily  soluble  in  water,  but  is 
insoluble  in  alcohol  and  ether. 

Those  eggs  which  develop  outside  of  the  mother-organism  must  contain 
all  the  elements  necessary  for  the  young  animals.  One  finds,  therefore,  in 
the  yolk  and  white  of  the  egg  an  abundant  quantity  of  albuminous  bodies 
of  different  kinds,  and  especially  a  phosphorized  proteid  in  the  yolk. 
Further,  we  also  find  lecithin  in  the  yolk,  which  seems  habitually  to  occur 
in  the  developing  cell.  The  occurrence  of  glycogen  is  doubtful,  and  the 
carbohydrates  are  perhaps  represented  by  a  very  small  amount  of  sugar  and 
glycoproteids.  On  the  contrary,  the  egg  contains  a  large  proportion  of  fat, 
which  doubtless  is  an  important  source  of  nutrition  and  respiration  for  the 
embryo.  The  cholesterin  and  the  lutein  can  hardly  have  a  direct  influence 
on  the  development  of  the  embryo.  The  egg  also  seems  to  contain  the 
mineral  bodies  necessary  for  the  development  of  the  young  animal.  The 
lack  of  phosphoric  acid  is  compensated  by  an  abundant  amount  of  phos- 
phorized organic  substance,  and  the  nucleoalbumin  containing  iron,  from 
which  the  haematogen  (see  page  377)  is  formed,  is  doubtless,  as  Buxge 
claims,  of  great  importance  in  the  formation  of  the  haemoglobin  containing 
iron.  The  silicic  acid  necessary  for  the  development  of  the  feathers  is  also 
found  in  the  egg. 

'  Cited  from  Krukeuberg,  Verb.  d.  phys.-chera.  Gesellsch.  in  Wiirzburg,  Bd.  17. 
'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  11. 
'L.  c. 

*  Du  Bois-Reymond's  Arch.,  1892. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  7. 

*  Cited  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  77. 


INCUBATION  OF  THE  EOO.  383 

During  the  period  of  incubation  the  egg  loses  weight,  chielly  due  to  loss 
of  water.  The  quantity  of  solids,  especially  the  fat  and  the  proteids, 
diminislies  and  the  egg  gives  ofY  not  only  carbon  dioxide,  but  also,  as 
LiEBEKMAXN  '  has  sliown,  nitrogen  or  a  nitrogenous  substance.  The  lo.-s 
is  compensated  by  the  absorption  of  oxygen,  and  it  is  found  that  during 
incubation  a  respiratory  exchange  of  gas  takes  place.  AVhile  the  quantity 
of  dry  substance  in  the  egg  during  this  period  always  decreases,  the  quantity 
of  mineral  bodies,  proteid,  and  fat  always  increases  in  the  embryo.  The 
increase  in  the  amount  of  fat  in  the  embryo  depends,  according  to  Liehkr- 
MAXX,  in  great  part  upon  a  taking  up  of  the  nutritive  yolk  in  the  abdominal 
cavity.  The  weight  of  the  shell  and  the  quantity  of  lime-salts  contained 
therein  remains  unchanged  during  incubation.  The  yolk  and  white 
together  contain  the  necessary  quantity  of  lime  for  development. 

The  most  complete  and  careful  chemical  investigation  on  the  develop- 
ment of  the  embryo  of  the  hen  has  been  made  by  Liekermaxn.  From  his 
researches  we  may  quote  the  following:  lu  the  earlier  stages  of  the  develop- 
ment, tissues  very  rich  in  water  are  formed,  but  on  the  continuation  of  the 
development  the  quantity  of  water  decreases.  The  absolute  quantities  of  the 
bodies  soluble  in  water  increase  with  the  development,  while  their  relative 
quantities,  as  compared  with  the  other  solids,  continually  decrease.  The 
c[uantities  of  the  bodies  soluble  in  alcohol  quickly  increase.  A  specially  im- 
portant increase  is  noticed  in  the  fat,  whose  quantity  is  not  very  great  even 
on  the  fourteenth  day,  but  after  that  it  becomes  considerable.  The  quantities 
of  albuminous  bodies  and  albuminoids  insoluble  in  water  grow  continually 
and  regularly  in  such  a  way  that  their  absolute  quantity  increases,  while 
their  relative  quantity  remains  nearly  nnchanged.  Ltebermaxn  found  no 
gelatin  in  the  embryo  of  the  hen.  The  embryo  does  not  contain  any 
gelatin-forming  substance  until  the  tenth  day,  and  from  the  fourteenth  day 
on  it  contains  a  body  which  when  boiled  with  water  gives  a  substance  similar 
to  chondrin.  A  body  similar  to  mucin  occurs  in  the  embryo  when  about 
six  days  old,  but  then  disappears.  The  quantity  of  haemoglobin  shows  a 
continual  increase  compared  with  the  weight  of  the  body.  Liebermaxx 
found  that  the  relationship  of  the  hajmoglobin  to  the  bodily  weight  was 
1  :  7:28  on  the  eleventh  day  and  1  :  421  on  the  twenty-first  day. 

The  tissue  of  the  placenta  lias  not  thus  far  been  the  subject  of  detailed  chemical 
investigation.  In  the  edges  of  the  ji'acenta  of  bitches  and  of  cats  a  crystullizable  orange, 
colored  pigment  (bilirubin?)  has  been  fdiind,  and  also  a  green  amorphous  pignient- 
Meckki/s  hamdtochlorin,  which  is  considered  as  biliverdin  by  Etti.'  Preterm  ques- 
tions ilie  identity  of  these  pigments  with  biliverdin. 

From  the  cotyledons  of  the  placentain  ruminantsa  white  or  faint  rose-colored  crer.my 
fluid,  tlie  uteriiw  milk,  can  be  obtained  by  pressure.  It  is  alkaline  in  reaction,  but 
becomes  acid  (piickly.     Its  specitic  gravity  is  1.033-1.040.     It  contains  as  form-elements 


'  Pfliiger's  Arch.,  Bd.  43. 

'  Maly's  Jahresber.,  Bd.  2,  S.  287. 

'  Die  BhUkrystalle  (Jena.  1871).  S.  189. 


384  OBGANS  OF  GENERATION. 

fat-globules,  small  grauules,  and  epithelium-cells.  We  have  found  81.2-120.9  p.  m. 
solids,  61.2-105.6  p.  m.  proteid,  about  10  p.  m.  fat,  and  3.7-8.2  p.  m.  ash  in  the  uterine 
milk. 

The  Huid  occurring  in  the  so-called  grape-mole  (mola  racemosa)  has  a  low  specific 
gravity,  1.009-1.012,  and  contains  19.4-26.3  p.  m.  solids  with  9-10  p.  m.  protein  bodies 
and  6-7  p.  ni.  ush. 

The  amniotic  fluid  in  women  is  thin,  whitish,  or  pale  yellow;  sometimes 
it  is  somewhat  yellowish  brown  and  cloudy.  White  flakes  separate.  The 
form-elements  are  viuciis-coijmscles,  ejyitheliiwi-ceUs,  fat-drops^  and  lanugo 
hair.  The  odor  is  stale,  the  reaction  neutral  or  faintly  alkaline.  The 
specific  gravity  is  1„002-1,028. 

The  amniotic  fluid  contains  the  constituents  of  ordinary  transudations. 
The  amount  of  solids  at  birth  is  hardly  20  p.  m.  In  the  earlier  stages  of 
pregnancy  the  fluid  contains  more  solids,  especially  proteids.  Among  the 
albuminous  bodies  Weyl  '  found  one  substance  similar  to  vitellin,  and  with 
great  probability  also  seralbumin^  besides  small  quantities  of  mucin. 
Sugar  is  regularly  found  in  the  amniotic  fluid  of  cows,  but  not  in  human 
beings.  On  the  contrary,  the  human  amniotic  fluid  contains  some  iirea 
and  allantoin.  The  quantity  of  these  may  be  increased  in  hydramnion 
(Prochownick,"  Harnack"),  which  depends  on  an  increased  secretion  by 
the  kidneys  and  skin  of  the  foetus.  Creatin  and  lactates  are  doubtful 
constituents  of  the  amniotic  fluid.  The  quantity  of  urea  in  the  amniotic 
fluid  is,  according  to  Prochownick,  0.16  p.  m.  In  the  fluid  in  hydram- 
nion, Prochownick  and  Harnack  found  respectively  0.34  and  0.48  p.  m. 
nrea.  The  chief  mass  of  the  solids  consists  of  salts.  The  quantity  of 
chlorides  (IS'aCl)  is  5.7-6.6  p.  m. 

'  Du  Bois-Reymond's  and  Reichert's  Arch.,  1876. 

»  Arch.  f.  Gynak.,  Bd.  11 ;  also  Maly's  Jahresber.,  Bd.  7,  S.  155. 

»  Berlin  klin.  Wochenschr.,  1888,  No.  41. 


CHAPTER   XIV. 
MILK. 

The  chemical  constituents  of  the  mammary  glands  have  been  little 
studied.  The  cells  are  rich  in  proteid  and  nucleoproteids.  Among  the 
latter  we  have  one  that  yields  a  not  well  studied  reducing  substance  on 
boiling  with  dilute  mineral  acids  which  gives  the  pentose  reactions.  The 
relation  this  nucleoproteid  bears  to  lactose  or  the  mother-substance  of  the 
same  has  not  been  determined.  According  to  15i:kt  '  the  secreting  glandg 
contain  a  body  which  on  boiling  with  dilute  mineral  acids  yields  a  reducing 
substance.  Such  a  substance,  which  acts  as  a  step  towards  the  formation  of 
lactose,  has  also  been  observed  by  Thierfeldkr.'  Fat  seems  to  be  a  never- 
failing  constituent  of  the  cell,  at  least  in  the  secreting  gland,  and  this  fat 
may  be  observed  in  the  protoplasm  as  large  or  small  globules  similar  to 
milk-globules.  The  extractive  bodies  of  the  mammary  glands  have  been 
little  investigated,  but  among  them  we  find  considerable  amounts  of  xanthin 
bodies. 

As  human  milk  and  the  milk  of  animals  are  essentially  of  the  same  con- 
stitution, it  seems  best  to  speak  first  of  the  one  most  thoroughly  inves- 
tigated, namely,  cow's  milk,  and  then  of  the  essential  properties  of  the 
remaining  important  kinds  of  milk. 

Cow's  Milk. 

Cow's  milk,  like  every  other  kind,  forms  an  emulsion  which  consists  of 
very  finely  divided  fat  suspended  in  a  solution  consisting  chiefly  of  proteid 
bodies,  milk-sugar,  and  salts.  Milk  is  non-transparent,  white,  whitish 
yellow,  or  in  thin  layers  somewhat  bluish  white,  of  a  faint,  insipid  odor  and 
mild,  faintly  sweetish  taste.  The  specific  gravity  is  1.038  to  1.0345  at 
+  15°  C. 

The  reaction  of  perfectly  fresh  milk  is  generally  amphoteric.  The 
extent  of  the  acid  and  alkaline  part  of  this  amphoteric  reaction  has  been 
determined  by  different  investigators,  especially  Tuorxer,  Sebelien,  and 
CouRANT."*     The  results  vary  with  the  indicators  used,  and  moreover  the 

'  Coinpt.  rend..  Tome  98. 

»  Pflugei's  Arcb.,  Bd.  32,  aud  Maly's  Jahiesber.,  Bd.  13.  S.  15G. 
»  Thorner,  Maly's  Jabresber.,  Bd.  23;  Sebeleiu,  ibid.;  Courant,  Pliilger's  Arcb.,  Bd. 
50. 

385 


386  MILK. 

uiilk  from  different  animals,  as  well  us  that  from  the  same  animal  at  differ- 
ent  times  during  the  lactation  period,   varies  somewhat.     CouRAi^T  has 

Is" 
determined  the  alkaline  part  by  —  sulpharic  acid,  nsing  bine  lacmoid  as 

indicator,  and  the  acid  part  by  —  caustic  soda,  using  phenolphthalein  as  in- 
dicator. He  found,  as  average  for  the  first  and  last  portions  of  the  milking 
of  twenty  cows,  that  100  c.c.  milk  had  the  same  akaline  reaction  for  blue 

N 
lacmoid  as  41  c.c.   —  caustic  soda,  and  the   same  acid  reaction  for  phe- 

nolphthalein  as  19.5  c.c,  —  sulphnric  acid. 

Milk  gradually  changes  when  exposed  to  the  air,  and  its  reaction 
becomes  more  and  more  acid.  This  depends  on  a  gradual  transformation, 
of  the  milk-sugar  into  lactic  acid,  caused  by  micro-organisms. 

Entirely  fresh  amphoteric  milk  does  not  coagulate  on  boiling,  but  forms 
a  skin  consisting  of  coagulated  casein  and  lime-salts,  which  rapidly  re-forms 
after  being  removed.  Even  after  passing  a  current  of  carbon  dioxide 
through  the  fresh  milk  it  does  not  coagulate  on  boiling.  In  jiroportion  as 
the  formatioa  of  lactic  acid  advances  this  behavior  changes,  and  soon  a 
stage  is  reached  when  the  milk,  which  has  previously  had  carbon  dioxide 
passed  through  it,  coagulates  on  boiling.  At  a  second  stage  it  coagulates 
alone  on  heating;  then  it  coagulates  by  passing  carbon  dioxide  alone  Avith- 
out  boiling;  and  lastly,  when  the  formation  of  lactic  acid  is  suflEicient,  it 
coagulates  spontaneously  at  the  ordinary  temperature,  forming  a  solid  mass. 
It  may  also  happen,  especially  in  the  warmth,  that  the  casein-clot  contracts 
and  a  yellowish  or  yellowish-green  acid  liquid  (acid  whey)  separates. 

Milk  may  undergo  various  fermentations.  Lactic-acid  fermentiilioii.  brought  about 
by  HuPPE's  lactic-acid  bacillus,  and  also  other  varieties  takes  first  place.  In  the  spon- 
taneous souring  of  milk  we  generally  consider  the  formation  of  lactic  acid  as  the  most 
essential  product.  Salkowski  and  Bltjmenthal  *  claim  that  a  formation  of  succinic 
acid  may  also  take  place,  and  in  certain  bacterial  decompositions  of  milk  they  claim  suc- 
cinic acid  and  no  laciic  acid  is  formed.  The  materials  from  which  these  two  acids  are 
forme  1  are  lacto.'^e  and  lacto-pbosphocaruic  acid.  Besides  lactic  and  succinic  acids, 
volatile  fatty  acids,  such  as  acetic  acid,  butyric  acid,  and  otliers,  may  be  formed  in  tlie 
bacterial  decomposition  of  milk. 

Milk  sometimes  undergoes  a  peculiar  kind  of  coagulation,  being  converted  into  a 
thick,  ropy,  slimy  mass  (thick  milk).  This  conversion  depends  upon  a  peculiar  change 
in  wliich  tlie  milk-sugar  is  made  to  undergo  a  slimy  transformation.  This  transforma- 
tion is  caused  by  a  special  organized  ferment.'' 

If  the  milk  is  sterilized  by  heating  and  contact  with  micro-organisms 
prevented,  the  formation  of  lactic  acid  may  be  entirely  stopped.  The 
formation  of  acid  may  also  be  prevented,  at  least  for  some  time,  by  many 


•  Virchow's  Arch.,  Bdd.  137  and  146. 

'  See  Schmidt-Mulheim,  PUuger's  Arch.,  Bd.  27,  and  G.  Leichmann,  Maly's  Jahres- 
l)er.,  Bd.  24,  S.  244. 


MILK-GLOBULES.  387 

antiseptics,  snch  as  salicylic  acid  (1  :  5000),  thymol,  boracic  acid,  and  otiier 
bodies. 

If  freshly  drawn  amphoteric  milk  is  treated  with  rennet,  it  coagulates 
quickly,  especially  at  the  temperature  of  tlie  body,  to  a  solid  mass  (curd) 
from  which  a" yellowish  iluid  (sweet  whey)  is  gradually  pressed  out.  This 
coagulation  occurs  without  any  change  in  tlie  reaction  of  the  milk,  and 
therefore  it  is  distinct  from  the  acid  coagulation. 

In  cow's  milk  we  find  as  form-elements  a  few  colostrum  corpuscles  (see 
Colostrum)  and  a  few  pale  nucleated  cells.  The  number  of  these  form- 
elements  is  very  small  compared  with  the  immense  amount  of  the  most 
essential  form-constituents,  the  milk-globules. 

The  Milk-globules.  These  consist  of  extremely  small  drops  of  fat  whose 
number  is,  according  to  Woll,'  l.OG-5.75  million  in  1  c.mm.,  and  whose 
diameter  is  0.00"^ 4-0. 004G  mm.  and  0.00;5T  mm.  as  average  for  different 
kinds  of  animals.  It  is  unquestionble  that  the  milk-globules  contain  fat, 
and  we  consider  it  as  positive  that  all  the  milk-fat  exists  in  them.  Another 
and  disputed  question  is  whether  the  milk-globules  consist  entirely  of  fat  or 
whether  they  also  contain  proteid. 

According  to  the  observations  of  Aschersox,'  drops  of  fat,  when 
dropped  in  an  alkaline  proteid  solution,  are  covered  with  a  fine  albuminous 
coat,  a  so-called  haptogen-memhrane.  As  milk  on  shaking  with  ether  does- 
not  give  up  its  fat,  or  only  very  slowly,  in  the  presence  of  a  great  excess  or 
ether,  and  as  this  takes  place  very  readily  after  the  addition  of  acids  or 
alkalies,  which  dissolve  proteids,  it  was  formerly  thought  that  the  fat- 
globules  of  the  milk  were  enveloped  in  a  proteid  coat.  A  true  membrane 
has  not  been  detected;  and  since,  when  no  means  of  dissolving  the  proteid 
is  resorted  to — for  example,  when  the  milk  is  precipitated  by  carbon  dioxide 
after  the  addition  of  very  little  acetic  acid,  or  when  it  is  coagulated  by 
rennet — the  fat  can  be  very  easily  extracted  by  ether,  the  theory  of  a  speciaL 
albuminous  membrane  for  the  fat-globules  has  been  generally  abandoned. 
The  observations  of  Quincke'  on  the  behavior  of  the  fat-globnles  in  an 
emulsion  prepared  with  gum  have  led,  at  the  present  time,  to  the  conclusion 
that  each  fat-globule  in  the  milk  is  surrounded  by  a  stratum  of  casein  solu, 
tion  by  means  of  molecular  attraction,  and  this  prevents  the  globules  front 
uniting  with  each  other.  Everything  that  changes  the  physical  property  of 
the  casein  in  the  milk  or  precipitates  it  must  necessarily  help  the  solution 
of  the  fat  in  ether,  and  it  is  in  this  way  that  the  alkalies,  acids,  and  rennet 
work. 


'  On  the  Conditions  influpncincr  tlie  Number  and  Size  of  Fat-globules  in  Cow's  Milk. 
Wisconsin  Expt.  Station.  Vol.  6.  1893. 
'*  Arcb.  f.  Auat.  u.  Physiol.,  1840. 
2  Pfliicrer's  Arch.,  Bd.  19. 


388  .  MILK. 

Storch  has  shown,  in  opposition  to  these  views,  that  the  milk-globules 
are  surrounded  by  a  membrane  of  a  special  slimy  substance.  This  substance 
is  very  insoluble,  contains  14.2-14.79^  nitrogen,  and  yields  a  sugar,  or  at 
least  a  reducing  substance,  on  boiling  with  hydrochloric  acid.  It  is  neither 
casein  nor  lactalbnmin,  but  seems  to  all  appearances  to  be  identical  with 
the  so-called  "stroma  substance"  detected  by  Eadenhause^st  and  Dani- 
LEWSKY.  Storch  was  able  to  show  that  this  substance  enveloped  the  fat- 
globules  like  a  membrane  by  staining  the  same  with  certain  dyes,' 

The  miXk-fat  has  a  rather  variable  specific  gravity,  which  according  to 
BoHR^  is  0.949-0.996  at  +  15°  C.  The  milk-fat,  which  is  obtained  under 
the  name  of  butter,  consists  in  great  part  of  the  neutral. fats  j9a?mi7»;z,  olein^ 
and  stearin.  Besides  these  it  contains,  as  triglycerides,  myristic  acid.,  small 
quantities  of  lutyric  acid  and  ca2Jroic  acid,  traces  of  caprylic  acid,  capric 
acids,  lauric  acid,  and  arachidic  acids.  Butter  which  has  been  exposed  to 
the  action  of  sunlight  contains  also  formic  acid  (Duclaux).  Milk-fat  also 
contains  a  small  quantity  of  lecithin  and  cholesterin,  also  a  yellow  coloring 
matter.  The  quantity  of  volatile  fatty  acids  in  butter  is,  according  to 
Duclaux,'  on  an  average  about  70  p.  m.,  of  which  37-51  p.  m.  is  butyric 
acid  and  20-33  p.  m.  is  caproic  acid.  The  non-volatile  fat  consists  of  ^V~tV 
olein/and  the  remainder  of  a  mixture  of  palmitin  and  stearin.^ 

The  milk-plasma,  or  that  fluid  in  which  the  fat-globules  are  suspended, 
contains  several  albuminous  bodies,  caseiii,  lactoglohulin,  and  lact  album  in, 
and  a  little  opalisin  (see  Human  Milk),  and  two  carbohydrates,  of  which 
only  one,  the  milh-sugar,  is  of  great  importance.  The  milk-plasma  also 
contains  extractive  bodies,  traces  of  urea,  creatin,  creatinin,  liypoxantliin  {?), 
lecithin,  cholesterin,  citric  acid  (Soxhlet  and  IIen"KEl),^  and  lastly  also 
mineral  bodies  and  gases. 

Casein.  This  protein  substance,  which  thus  far  has  been  detected  posi- 
tively only  in  milk,  belongs  to  the  nucleoalbumins,  and  differs  from  the 
albuminates  chiefly  by  its  containing  phosphorus  and  by  its  behavior  with 
the  rennet  en/, /me.  Casein  from  cow's  milk  has  the  following  composition: 
C  53.0,  H  7.0,  N  15.7,  S  0.8,  P  0.85,  and  0  22.65^.  Its  specific  rotation 
is,  according  to  IIoppe-Seyler,"  somewhat  variable;  in  neutral  solution  it 
is  «(D)  =  —  80°.     The  question  whether  the  casein  from  different  kinds 

'  V.  Storch,  see  Maly's  Jahresber.,  Bd.  27  ;  Radeiibauseu  and  Danilewsky,  For- 
schuugea  auf  dem  Gebiete  der  Viehlialtuug  (Bremen,  1880),  Heft  9. 

«  Maly's  Jahresber.,  Bd.  10,  S.  182. 

'  Compt.  rend..  Tome  104. 

■•  Various  statements  as  to  the  composition  of  milk-fat  can  be  found  in  Kocfoed, 
Bull.  d.  I'Acad.  Danoi.se,  1891,  and  Wanklyu,  Chemical  News,  Vol.  63. 

'"  Cited  from  F.  Soldner,  Die  Salze  der  Milch.,  etc.  Laudwirthsch.  Versuchsstation, 
Bd.  35.     Separatabziig,  S.  18. 

'  Handb.  d.  physiol,  u.  pathol.  chem.  Analyse,  6.  Aull.,  S.  259. 


CASEIN.  389 

of  milk  is  identical  or  whether  tl^.ere  aro  several  different  caseins  lias  not 
been  positively  determined. 

Casein  when  dry  appears  like  a  fine  white  powder  which,  after  heating  to 
100°  C.  or  somewhat  above,  shows  the  properties  and  Bolnbilities  of  freshly 
precipitated,  still-moist  casein.  Casein  is  only  slightly  solu])le  in  water  or 
in  nentral-salt  solutions.  According  to  Arthus'  it  is  rather  easily  soluble 
in  a  I'fo  solution  of  sodium  flnoride,  ammonium,  or  potassium  oxalate.  It  , 
acts  like  a  rather  strong  acid,  dissolves  readily  in  water  on  the  addition  of 
very  little  alkali,  forming  a  neutral  or  acid  liquid,  and  lastly  it  dissolves  in 
water  in  the  presence  of  calcium  carbonate,  from  which  it  expels  the  carbon 
dioxide.  If  casein  is  dissolved  in  lime-water  and  this  solution  carefully 
treated  with  very  dilute  phosphoric  acid  until  it  is  neutral  in  reaction,  the 
casein  appears  to  remain  in  solution,  but  is  probably  only  swollen  as  in 
milk,  and  the  liquid  contains  at  the  same  time  a  large  quantity  of  calcium 
phosphate  without  any  precipitate  or  any  suspended  particles  being  visible. 
The  casein  solutions  containing  lime  are  opalescent  and  have  on  warming 
the  appearance  of  milk  deficient  in  fat.  Therefore  it  is  not  impossible  tliat 
the  white  color  of  the  milk  is  due  partly  to  the  casein  and  calcium  phos- 
phate. SoLDXER  has  prepared  two  calcium  combinations  of  casein  with 
1.55  and  2.36/'©  CaO,  and  these  combinations  are  designated  di-  and 
tricalcium  casein  by  Courant.' 

Casein  solutions  do  not  coagulate  on  boiling,  but  are  covered,  like  milk, 
with  a  skin.  They  are  precipitated  by  very-  little  acid,  but  the  presence  of 
neutral  salts  retards  the  precipitation.  A  casein  solution  containing  salt  or 
ordinary  milk  requires,  therefore,  more  acid  for  precipitation  than  a  salt- 
free  solution  of  casein  of  the  same  concentration.  The  precipitated  casein 
dissolves  very  easily  again  in  a  small  excess  of  hydrochloric  acid,  but  less 
easily  in  an  excess  of  acetic  acid.  These  acid  solutions  are  precipitated  by 
mineral  acids  in  excess.  Casein  is  precipitated  from  neutral  solutions  or 
from  milk  by  common  salt  or  magnesium  sulphate  in  substance  without 
changing  its  properties."  Metallic  salts,  such  as  alum,  zinc  sulphate,  and 
copper  sulphate,  completely  precipitate  the  casein  from  neutral  solutions. 

The  property  which  is  the  most  characteristic  of  casein  is  tliat  it  coagu- 
lates with  rennet  in  the  presence  of  a  sufficiently  great  amount  of  lime-salts. 
In  solutions  free  from  lime-salts  the  casein  does  not  coagulate  with  rennet; 
but  it  is  changed  so  that  the  solution  (even  if  the  enzyme  is  destroyed  by 

'  M.  Arthus,  Theses  presentees  tl  la  faculte  des  sciences  de  Paris,  1893.  { 

'  Soldncr,  Die  Sulze  der  Milcli,  etc.;  Courant,  1.  c.     In  regard  to  the  salts  of  casein 

see  the  recent  investigations  of  Soldncr,  ^Maly's  Jahrcsber.,  Bd.   25,   and  J.   ROhmann. 

Berlin,  klin.  Wochenschr.,  1895. 

^  Moniczewski  obtained  microscopical  spheroliths,  consisting  of  proteid  and  45':^  asb 

from   an  animoniacal  solution  of  casein  and  magnesium  chloride  (Zeitschr.  f.  physiol. 

Chem.,  Bd.  21). 


390  MILE. 

heating)  yields  a  coagulated  mass,  having  the  properties  of  curd,  if  lime- 
salts  are  added.  The  rennet  enzyme,  rennin,  has  therefore  an  action  on 
casein  even  in  the  absence  of  lime-salts,  and  these  last  are  only  necessary 
for  the  coagulation  or  the  separation  of  the  curd.  This  fact,  which  was 
first  jjroved  by  Hammarsten",^  has  lately  been  confirmed  by  Arthus  and 
Pages.' 

The  curd  formed  on  the  coagulation  of  milk  contains  large  quantities  of 
calcium  phosphate.  According  to  Soxhlet  and  Soldner,  the  soluble 
lime-salts  are  of  essential  importance  only  in  coagulation,  while  the  calcium 
phosphate  is  without  importance.  According  to  Courant  the  calcium 
casein  on  coagalation  may  carry  down  with  it,  if  the  solution  contains 
dicalcinm  phosphate,  a  part  of  this  as  tricalciam  phosphate,  leaving  mono- 
calcium  phosphate  in  the  solution.  The  chemical  processes  which  take 
place  in  the  rennet  coagulation  have  not  been  thoroughly  investigated ;  still 
several  observations  seem  to  show  that  casein  splits  partly  into  a  difiicultly 
soluble  body,  paracaaein  or  curd.,  whose  composition  closely  resembles  that 
of  casein  and  which  forms  the  chief  product,  and  partly  into  an  easily 
soluble  substance,  similar  to  albumose,  lohey-proteid,  which  is  deficient  in 
carbon  and  nitrogen  (50.3^  C  and  13.2^  N,  Koster^)  and  which  is  pro- 
duced in  very  small  quantities.  Paracasein  Ms  not  further  changed  ^  by  the 
rennet  enzyme,  and  it  has  not  the  property,  to  the  same  extent,  of  holding 
calcium  phosphate  in  solution  as  casein  has.  In  regard  to  other  enzymes 
acting  like  rennin  see  Chapter  IX. 

In  the  digestion  of  casein  with  pepsin  hydrochloric  acid  pseudonuclein  is 
split  off,  and  the  quantity  thus  split  off  is  very  variable,  as  shown  by  the 
researches  of  Salkowski,  Hahn,  Moraczewski  and  Sebelien.  °  The 
amount  of  phosphorus  in  the  obtained  pseudonncleins  also  varies  consider- 
ably. According  to  Salkowski  the  quantity  split  off  is  dependent  upon 
the  relationship  between  the  casein  and  digestion  fluid,  namely,  the  quantity 
of  pseudonncleins  diminishes  as  the  pepsin  hydrochloric  acid  increases.  In 
the  presence  of  500  grms.  pepsin  hydrochloric  acid  to  1  grm.  casein  Sal- 
kowski digested  the  casein  completely  without  obtaining  any  pseudonuclein. 

'  Muly's  Jahresber.,  Bdd.  2  and  4  ;  also  Haramarsten,  Zur  Keuntuissdes  Kaseius  mid 
der  Wirkuug  des  Labfennentes.  Nova  Acta  Rcsr.  Soc.  Scient.  Upsala,  1877.  Festschrift. 

'  Arch,  de  Physiol.  (5),  Tome  2,  and  Mem.  Soc.  biol.,  Tome  43. 

=  See  Maly's  Jahresber.,  Bd.  11,  S.  14. 

"•  It  has  been  recently  proposed  to  designate  the  ordinary  casein  as  caseiuogen,  and 
the  curd  as  casein.  Although  such  a  proposition  is  theoretically  correct,  it  leads  in 
practice  to  confusion.  On  this  account  the  author  calls  the  curd  paracasein,  according 
to  Schulze  and  ROse  (Landwirthsch.  Versuchsstat.,  Bd.  31). 

'  See  llanimarsten,  Zeitschr.  f.  physiol.  Chem.,  Bd.  22.  In  regard  to  recent  work 
on  the  coagulation  of  milk  we  must  mention  Hillmann,  Milchzeituug,  Bd.  25  ;  Benja- 
min, Virchow's  Arch.,  Bd.  145  ;  and  Liirc^ber,  PUllgcr's  Arcli.,  Bd.  69.* 

•  Salkowski  and  llahn,  Pfltlger's  Arch.,  Bd.  59  ;  Salkowski,  ibid.,  Bd.  63  ;  v.  Mora- 
czewski, Zeitschr.  f.  physiol.  Chem.,  Bd.  20  ;  Sebelien,  ibid.,  Bd.  20. 


L  ACT  ALBUM  IN  AND   MILK-SUGAR.  391 

In  peptic  as  well  as  tryptic  digestion  a  part  of  the  organic  combined 
phosphorus  is  split  off  as  orthoplios})horic  acid;  the  (jtiantity  increasing  as 
the  digestion  progresses.  Another  part  of  the  phosphorus  is  retained  in 
orgunic  combination,  in  the  albumoses  as  well  as  in  the  true  peptone 
(Salkowski,  Bii'Fi,  Alexandkii  '). 

Casein  may  be  prepared  in  the  following  way:  The  milk  is  diluted  with 

4  vols,  water  and  the  mixture  treated  with  acetic  acid  to  0.75  to  1  p.  m. 
Casein  thus  obtained  is  i>urilied  by  repeated  solution  in  water  with  the  aid 
of  the  smallest  quantity  of  alkali  possible,  by  filtrating  and  reprecipitating 
with  acetic  acid,  and  thoroughly  washing  with  water.  Most  of  the  milk-fat 
is  retained  by  the  filter  on  the  first  filtration,  and  the  casein  contaminated 
with  traces  of  fat  is  purified  by  treating  with  alcohol  and  ether. 

Ladoglobulin  was  obtained  by  Sebelein  from  cow's  milk  by  saturating 
it  with  ^aCl  in  substance  (which  precipitated  the  casein),  and  saturating 
the  filtrate  with  magnesium  sulphate.  As  far  as  it  has  been  investigated  it 
liad  the  properties  of  serglobulin;  the  globulin  isolated  by  Tiemann'  from 
colostrum   had    nevertheless  a  markedly  low  quantity  of  carbon,   namely, 

Lactalbumin  was  first  prepared  in  a  pure  state  from  milk  by  Sebelein.* 
Its  composition  is,  according  to  Sebelein,  C   52.19,  H  7.18,  N  15.77, 

5  1.73,  0  'l'i.Vo<^.  Lactalbumin  has  the  properties  of  the  albumins.  It 
coagulates,  according  to  the  concentration  and  the  amount  of  salt  in  solu- 
tion, at  +  '^'^°  to  8-4°  C.  It  is  similar  to  seralbumin,  but  differs  from  it  in 
having  a  considerably  lower  specific  rotatory  power:  <a'(D)  =  —  87°. 

The  principle  of  the  preparation  of  lactalbumin  is  the  same  as  for  the 
preparation  of  seralbumin  from  serum.  The  casein  and  the  globnlin  are 
removed  by  MgSO,  in  substance,  and  the  filtrate  treated  as  previously  stated 
(page  131). 

The  occurrence  of  other  albuminous  bodies,  such  as  albumose  and  peptones,  in  milk 
lias  not  been  positively  proved.  These  bodies  are  easily  produced  as  laboratory  products 
from  the  other  proteids  of  the  milk.  Such  a  laboratory  product  is  Millon's  and  Co- 
m.\ille'8  Uicioprotein.  which  is  a  mi>;ture  of  a  little  casein  with  changed  albumin,  and 
albumose,''  wliich  is  formed  by  chemical  action.  In  regard  to  opalisin  see  Human 
Milk,  i>age  398. 

Milk  also  contains,  according  to  Siegfiiied,'  a  nudeon,  related  to  phosphocarnic 
acid,  and  which  yields  fermentation  lactic  acid  (instead  of  paralactic  acid)  and  a  special 
caruic  acitl,  orj/lic  acid  (instead  of  muscle  carnic  acid"),  as  cleavage  products.  Lacto- 
phospliocarnic  acid  maybe  precipitated  as  an  iron  combination  from  the  milk  freed  from 
casein  and  coagulable  proteids  as  well  as  earthy  phosphates. 

Milk-sugar,  lactose,  C,  JI„0,,  -f  11,0.  This  sugar  with  the  absorption 
of  water  can  be  split  into  two  glucoses,  dextrose  and  galactose.     It  yields 

•  Salkowski,  1.  c;  Biffi,  Virchow's  Arch.,  Bd.  152;  Alexander,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  25. 

'  Zeitschr.  f.  physiol.  Chem..  Bd.  25. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  9.  , 

*  See  Hammarsten,  Ueber  das  Laktoproteiu,  Nord.  med.  Arkiv.,  Bd.  8,  No.  10  ;  also 
Maly's  Jahresber.,  Bd.  6.  S.  13. 

»  Zeitschr.  f.  physiol.  Chem.,  Bdd.  21  and  22. 


392  MILE. 

macic  acid,  besides  other  organic  acids,  by  the  action  of  dilute  nitric  acid^ 
Levulinic  acid  is  formed,  besides  formic  acid  and  hnmin  substances,  by  the 
stronger  action  of  acids.  By  the  action  of  alkalies  amongst  other  products 
we  find  lactic  acid  and  pyrocatechin. 

Milk-sngar  occurs,  as  a  rule,  only  in  milk,  but  it  has  also  been  found  in  . 
the  urine  of  jjregnant  women  on  stagnation  of  milk,  as  well  as  in  the  urine 
after  partaking  of  large  quantities  of  the  same  sugar.     According  to  tiie 
statements  of  Pappel  and  Richmond  '  the  milk  of  the  Egyptian  buffalo 
does  not  contain  milk-sugar,  but  a  sugar  called  tewfihose. 

Milk-sngar,  of  which,  according  to  Taneet,  we  have  three  modifications 
(see  Chapter  III),  occurs  ordinarily  as  colorless  rhombic  crystals  with  1  mol. 
of  water  of  crystallization,  which  is  driven  off  by  slowly  heating  to  100°  C.,_ 
but  more  easily  at  130-140°  C.  At  170°  to  180°  C.  it  is  converted  into  a 
brown  amorphous  mass,  lactocaramel,  C^Hj^O^.  On  quickly  boiling  down 
a  milk-sugar  solution,  anhydrous  milk-sugar  separates  out.  Milk-sugar 
dissolves  in  6  parts  cold  or  in  2.5  parts  boiling  water;  it  has  a  faintly 
sweetish  taste.  It  does  not  dissolve  in  ether  or  absolute  alcohol.  Its  solu- 
tions are  dextrogyrate.  The  rotatory  power,  which  on  heating  the  solution 
to  100°  C.  becomes  constant,  is  «'(D)  =  +  52.5°.  Milk-sugar  combines 
with  bases;  the  alkali  combinations  are  insoluble  in  alcohol. 

Milk-sugar  is  not  fermentable  with  pure  yeast.  It  undergoes,  on  the 
contrary,  alcoholic  ferment-ation  by  the  action  of  certain  schizomycetes,  and 
according  to  E.  Eischer^  the  milk-sugar  is  first  split  into  glucose  and 
galactose  by  an  enzyme,  lactase,  existing  in  the  yeast.  The  preparation  of 
milk-wine,  '■^  Tciimyss,''''  from  mare's  milk  and  '■'■  IcepMr''''  from  cow's  milk 
is  based  upon  this  fact.  Other  micro-organisms  also  take  part  in  this 
change,  causing  a  lactic-acid  fermentation  of  the  milk-sugar. 

Lactose  responds  to  the  reactions  of  grape-sugar,  such  as  Moore's, 
Trommer's,  and  Eubxer's,  and  the  bismuth  test.  It  also  reduces  mer- 
curic oxide  in  alkaline  solutions.  After  warming  with  phenylhydrazin 
acetate  it  gives  on  cooling  a  yellow  crystalline  precipitate  of  phenyl- 
lactosazon,  C^JIj^lNr^O^.  It  differs  from  cane-sugar  by  giving  positive 
reactions  with  Moore's  or  Trommer's  and  the  bismuth  test,  and  also  in  that 
it  does  not  darken  when  heated  with  anhydrous  oxalic  acid  to  100°  C.  It 
differs  from  grape-sugar  and  maltose  by  its  solubility  and  crystalline  form, 
but  especially  by  its  not  fermenting  with  yeast  and  by  yielding  mucic  acid 
with  nitric  acid. 

Eor  the  preparation  of  milk-sugar  we  make  use  of  the  by-product  in  the 
preparation  of  cheese,  the  sweet  whey.  The  proteid  is  removed  by  coagula- 
tion with  heat,  and  the  filtrate  evaporated  to  a  syrup.  The  crystals  which 
separate  after  a  certain  time  are  recrystallized  from  water  after  decolorizing 

'  Journ  Cbem.  Soc,  London,  1894,  p.  754. 
'  Ber.  (1.  (leutsch.  chem,  Gesellsch.,  Bd.  27. 


ANALYSIS   OF  MILK.  393 

with  animal  charcoal.  A  pnre  preparation  may  be  obtained  from  the  com- 
mercial milk-sugar  by  repeated  recrystallizatioii.  The  quantitative  estima- 
tion of  milk-sugar  may  in  part  be  performed  by  the  polaristrobometer  and 
partly  by  means  of  titration  with  Fi:hlin(;'s  solution.  10  c.c.  of  FKHLiN(i's 
solution  corresjiotuls  to  0.0070  grm.  milk-sugar  in  O.o-l.oj^  solution  and 
boiling  for  G  Hiinutes  (in  regard  to  Feiilix(;\s  solution  and  the  titration  of 
sugar  see  Chapter  XV). 

RiTTHAirsKN  lijis  foiiiul  another  curbnliydrale  in  milk  which  is  soluble  in  w.-iler, 
nou-cryst:tlli/.al)if,  which  has  a  faint  -educing  action,  and  which  yields  on  boiling  wiili 
an  acid  a  body  having  a  greater  reducing  power.  Landweuk  considers  this  as  animal 
gum,  and  Bkc  uamt  '  as  dextrin. 

The  ir.iiwral  bodies  of  milk  will  be  treated  in  connection  with  its  quanti- 
tative composition. 

The  methods  for  the  quantitative  analysis  of  milk  are  very  numerous, 
and  as  they  cannot  all  be  treated  of  here,  we  will  give  the  chief  points  of  a 
few  of  the  most  trustworthy  and  most  frequently  employed  methods. 

In  determining  the  solids  a  carefully  weighed  quantity  of  milk  is  mixed 
with  an  equal  weight  of  heated  quartz  sand,  fine  glass  powder,  or  asbestos. 
The  evaporation  is  first  done  on  the  water-bath  and  finished  in  a  current  of 
carbon  dioxide  or  hydrogen  not  above  100°  C. 

The  mineral  bodies  are  determined  by  ashing  the  milk,  using  the  i)re- 
cautions  mentioned  in  the  text-books.  The  results  obtained  for  the  phos- 
phoric acid  are  incorrect  on  account  of  the  burning  of  phosphorized  bodies, 
such  as  casein  and  lecitliin.  We  must  therefore,  according  to  Soldxer, 
subtract  'lb<fc  from  the  total  phosphoric  acid  found  in  the  milk.  The 
quantity  of  sulphate  in  the  ash  also  depends  on  the  burning  of  the  proteids. 

In  the  determination  of  the  total  amount  of  proteids  we  make  use  of 
Rittiiausen's  method,  namely,  precipitate  the  milk  with  copper  sulphate 
according  to  the  modification  suggested  by  Munk.^  He  precipitates  all 
the  proteids  by  means  of  copper  oxyhydrate  at  boiling  heat,  and  determines 
the  nitrogen  in  the  precipitate  by  means  of  K.teldaiil's  method.  This 
modification  gives  exacter  results. 

The  older  method  of  Puls  and  Stexberg,'  where  the  precipitant  is 
alcohol,  is  too  complicated  and  not  sufficiently  reliable.  Sebelien*  has 
suggested  a  very  good  modification.  3-4  grms.  of  milk  are  diluted  with  an 
equal  volume  of  water,  a  little  common-salt  solution  added,  and  precipitated 
with  an  excess  of  tannic  acid.  The  precipitate  is  washed  with  cold  water, 
and  then  the  quantity  of  nitrogen  determined  by  Kjeldaiil's  method. 
The  total  nitrogen  found  when  multiplied  by  G.37  (casein  and  lactalbumin 
contain  both  15.7^  nitrogen)  gives  the  total  quantity  of  albuminous  bodies. 
This  method,  which  is  readily  performed,  gives  very  good  results.  I.  Muxk 
used  this  method  in  the  analysis  of  Avoman's  milk.  In  this  case  the  quantity 
of  nitrogen  found  must  be  multiplied  by  0.34.  The  objection  to  this  and 
other  methods  where  the  proteids  are  precipitated,  is  that  perhaps  other 

'  Ritthauscn.  Joiirn.  f.  prakt.  Chem.  (N.  F  ).  Bd.  15  ;  Landwehr,  foot-note  2,  page 
46  ;  Bechamp,  Bull.  sec.  chim.  (3),  Tome  6. 

*  Ritthauseu,  Journ.  f.  prakt.  Cbem.  (N.  F.),  Bd.  15  :  I.  Munk,  Virchow's  Arch.,  Bd. 
134. 

»  Puis,  PflUger's  Arch.,  Bd.  13  ;  Stenberg,  Maly's  Jahresber.,  Bd.  7,  S.  169. 

^Zeitachr.  f.  physiol.  Chem.,  Bd.  13. 


394  MILK. 

bodies  (extractives)  may  be  carried  down  at  the  same  time  (Camerer  and 
SoLDXER  ').     It  is  undecided  to  what  extent  this  takes  place. 

Apiirt  of  the  nitiogeu  in  the  milk  exists  as  extractives,  and  this  nitrogen  is  calculated 
as  the  difference  between  the  total  nitrogen  and  the  protein  nitrogen.  According  to 
Mcnk's  analyses  about  y\  of  the  total  nitrogen  belongs  to  the  extractives  in  cow's  milk, 
and  t'y  in  woman's  milk.  Camerek  and  Soldner  determine  the  nitrogen  in  the  filtrate 
from  the  tanuic-acid  precipitate  by  Kjeldahl's  method,  and  also  according  to  Hufner's 
method  (hypobromite).  In  this  way  they  found  11  milligrammes  nitrogen  as  urea,  etc. 
(nitrogen  according  to  Hupner),  in  100  grammes  woman's  milk.  Of  the  remaining 
nitrogen  SS%  came  from  the  proteids  and  the  remainder  from  nitrogenous  extractives. 
In  cow's  milk  they  found  18  milligrammes  nitrogen  according  to  Hufner,  and  98^ 
of  the  remainder  belonged  to  the  proteid  bodies. 

To  determine  the  casein  and  alhumins  separately  we  may  make  use  of 
the  method  first  stiggested  by  Hoppe-Seyler  and  Tolmatscheff,"  in  which 
the  casein  is  precipitated  by  magnesitim  snlphate.  According  to  tSEBELiEisr, 
the  milk  is  diluted  with  its  own  volume  of  a  saturated  magnesium-sitlphate 
solution,  then  saturated  with  the  salt  in  substance,  and  the  precipitate  then 
filtered  and  washed  with  a  saturated  magnesium-sulphate  soltttion.  The 
nitrogen  is  determined  in  the  precipitate  by  Kjeldahl's  method,  and  the 
qtiantity  of  casein  determined  by  multiplying  the  result  by  6. 37.  The  quan- 
tity of  lactalbnmin  may  be  calculated  as  the  difference  between  the  casein 
(+  globulin)  and  the  total  proteids  found.  The  lactalbumin  may  also  be 
precipitated  by  tannic  acid  from  the  filtrate  containing  MgSO^  from  the 
casein  precipitate,  diluted  with  water,  and  the  nitrogen  determined  by 
K.teldahl's  method  and  the  result  multiplied  by  G.37. 

Schlossmaxn  '  suggests  an  alum  solution,  which  precipitates  the  casein, 
in  separating  the  casein  from  the  other  proteids.  The  proteid  can  be  pre- 
cipitated from  the  filtrate  by  tannic  acid.  The  precipitate  is  used  to  deter- 
mine the  nitrogen  by  K.jeldahl's  method. 

The/a^  is  gravimetrically  determined  by  thoroughly  extracting  the  dried 
milk  with  ether,  evaporating  the  ether  from  the  extract,  and  weighing  the 
residue.  The  fat  may  be  determined  by  aerometric  means  by  adding  alkali 
to  the  milk,  shaking  with  ether,  and  determining  the  specific  gravity  of  the 
fat  solution  by  means  of  Soxhlet's  apparatus.  In  determining  the  amount 
of  fat  in  a  large  number  of  samples  the  lactocrit  of  De  Laval  may  be  used 
with  success.  The  milk  is  first  mixed  with  an  equal  volume  of  a  mixture 
of  glacial  acetic  and  concentrated  sulphuric  acid,  warmed  7-8  minutes  on 
the  water-bath,  the  mixture  placed  in  graduated  tubes,  and  these  in  the 
centrifugal  machine  at  +  50°  C.  The  height  of  the  layer  of  fat  gives  its 
quantity.  The  numerous  and  very  exact  analyses  of  Nilson  have  shown 
that  with  milks  containing  small  quantities  of  fat,  below  1.5^,  the  older 
corrections  are  unnecessary,  and  that  this  method  gives  excellent  results  if 
we  use  lactic  acid  treated  with  ofo  hydrochloric  acid  instead  of  the  above 
mixture  of  glacial  acetic  acid  and  sulphuric  acid.  There  are  numerous  other 
methods  for  determining  milk-fat,  among  them  Gottlieb's  method,  which 
is  simple  and  exact  (Weibull''). 

In  determining  the  milk-sugar  the  proteids  are  first  removed.     For  this 

'  Zeitschr.  f.  Biologie,  Bdd.  33  and  36. 
^  Hoppe-Seyler,  Med.-chem.  Untersuch.,  S.  272. 
3  Zeitschr.  f.  physiol.  Chera.,  Bd.  22. 

*Nllson,  Maly's  Jahresber.,  Bd.  21;  Gottlieb,  Maly's  Jahresber.,  Bd.  20;  "Weibull, 
Landtburcks.  akad.  Handl.  o.  tidskr.  Stockholm,  1898. 


coMPOsirroy  of  co^y's  milk.  396 

purpose  we  precipitate  either  with  alcohol,  which  must  be  evaporated  from 
the  filtrate,  or  by  dilntiiifr  witl)  water,  and  removing  the  casein  by  tlie 
addition  of  a  little  acid,  and  the  lactalbumin  by  coagfulation  at  boiling  heat. 
The  sugar  is  determined  by  titration  with  Fehlixg's  or  Kxapp's  solution 
(see  Chap.  XV).  The  principle  of  titration  is  the  same  as  for  the  titration 
of  sugar  in  urine:  10  c.c.  of  Feeling's  solution  corresponds  to  0.0G7G 
grm.  milk-sugar;  10  c.c.  of  Kxapp's  solution  corresponds  to  0.0311-0.0310 
grm,  milk-sugar,  when  the  saccharine  liquid  contains  about  \-\'i  sugar. 
In  regard  to  the  modus  opermidi  of  the  titration  we  must  refer  the  reader 
to  more  complete  works  and  to  Chapter  XV. 

Instead  of  these  volumetric  determinations  other  methods  of  estimations, 
such  as  Allien 's  method,  the  polariscope  method,  and  others,  may  be  used. 
In  calculating  the  analysis  it  is  of  importance,  as  suggested  by  Camereu  and 
SoLDNER,  in  determining  the  solids  that  the  milk-sugar  in  the  residue  is 
anhydrous. 

The  quantUative  composition  of  cow's  milk  is  naturally  very  variable. 
The  average  obtained  by  Konig  '  is  as  follows  in  1000  parts: 

Water.  Solids.  Casein.  Albumin.  Fats.  Sugar.  Salts. 

871.7  128.3  30.2  5.3  36.9  48.8  7.1 


35.5 

The  quantity  of  mineral  bodies  in  1000  parts  of  cow's  milk  is,  according 
to  the  analyses  of  Soldner,  as  follows:  K,0  1.72,  Na,0  0.51,  CaO  1.98, 
MgO  0.20,  P,Oj  1.82  (after  correction  for  the  pseudonuclein),  CI  0.98  grms. 
Bunge'  found  0.0035  grm.  Fe„03.  According  to  Solijner,  the  K,  Xa, 
aii.l  CI  are  found  in  the  same  quantities  in  whole  milk  as  in  milk-serum. 
Of  the  total  phosphoric  acid  36-56,i;  and  of  the  lime  53-72;:^  is  not  in  solution. 
A  i^rt  of  this  lime  is  combined  with  the  casein;  the  remainder  is  found 
nnited  with  the  phosphoric  acid  as  a  mixture  of  dicalcium  and  tricalcium 
phosphate,  which  is  kept  dissolved  or  suspended  by  the  casein.  The  bases 
are  in  excess  of  the  mineral  acids  in  the  milk-serum.  The  excess  of  the  first 
is  combined  with  organic  acids,  which  correspond  to  2.5  p.  m,  citric  acid 
(Soldner). 

The  gases  of  the  milk  consist  chiefly  of  CO, ,  besides  a  little  N  and  traces 
of  0.  Pfluger'  found  10  vols,  per  cent  C0„  and  0.6  vol.  per  cent  N, 
calculated  at  0°  C.  and  760  mm.  pressure. 

The  variation  in  the  composition  of  cow's  milk  depends  on  several  cir- 
cumstances. 

The  colostnim,  or  the  milk  which  is  secreted  before  calving  and  in  the 
first  few  days  after,  is  yellowish,  sometimes  alkaline,  but  often  acid,  of 
higher  specific  gravity,  1.0-16-1. 080,  and  richer  in  solids  than  ordinary 
milk.  The  colostrum  contains,  besides  fat-globules,  an  abundance  of  colos- 
trum-corpuscles— nucleated  granular  cells  0.005-0.025   mm.   in   diameter 

'  Cbeuiie  der  raenscblichen  Niihrungs-  unci  Genussmittel,  3.  Aufl. 
'  Zeitschr.  f.  Biologic,  Bd.  10. 
'PflUger's  Arch.,  Bd.  2. 


396  MILK. 

■with  abundant  fat-granales  and  fat-globnles.  The  fat  of  colostrum  has  a. 
somewhat  higher  melting-point  and  is  poorer  in  volatile  fatty  acids  than  the 
fat  from  ordinary  milk  (NiLSOX  ').  The  quantity  of  cholesterin  and  lecithin 
is  generally  greater.  The  most  apparent  difference  between  it  and  ordinary 
milk  is  that  colostrum  coagulates  on  heating  to  boiling  because  of  the 
absolute  and  relatively  greater  quantities  of  globulin  and  albumin  it  con- 
tains." The  composition  of  colostrum  is  very  variable.  KoNiG  gives  as 
average  the  following  figures  in  1000  j^arts: 

Water.  Solids.  Casein.        Albumin  and  Globulin.        Fat.  Sugar.  Salts. 

746.7  253.3  40.4  136.0  35.9  26.7  15.6 

The  constitution  of  milk  is  changed  during  lactation,  and  it  becomes 
richer  in  casein  but  poorer  in  fat  and  milk-sugar.  The  evening  milk  is 
richer  in  fat  than  the  morning  milk  (Alex.  Muller  and  Eisexstuck^ 
NiLSON  and  others^).  The  breed  of  the  animal  also  has  a  great  influence 
on  the  milk. 

The  influence  food  exercises  upon  the  composition  of  milk  Avill  be  dis- 
cussed in  connection  with  the  chemistry  of  the  milk  secretion. 

In  the  following  we  give  the  average  composition  of  skimmed  milk  and  certain 
other  preparations  of  milk: 

/                                      Water.  Proteids.  Fat.  Sugar.  Lactic  Acid.  Salts. 

Skimmed  milk 906.6  31.1  7.4  47.5  ....  7.4 

Cream 655.1  36.1  267.5  35.2  ....  6.1 

Buttermilk 902.7  40.6  9.3  37.3  3.4  6.7 

AVhey 9:32.4  8.5  2.3  47.0  3.8  6.5 

KuMYSS  and  kephir  are  obtained,  a^;  above  stated,  by  the  alcoholic  and  lactic-acid 
fermentation  of  the  milk-sugar,  the  first  from  mare's  milk  and  the  last  from  cow's  milk. 
Large  quaulitiesof  carbon  dioxide  are  formed  thereby,  and  besides  the  albuminous  bodies 
of  the  milk  :ne  partly  converted  into  albumoses  and  peptones,  which  increase  the  di- 
gestibility. The  quantity  of  lactic  acid  in  these  preparations  may  be  about  10-20  p.  m. 
The  quantity  of  alcohol  varies  from  10  to  35  p.  m. 

Milk  of  other  Animals.  Goat's  milk  has  a  more  yellowish  color  and  another, 
more  specific,  odor  than  cow's  milk.  The  coagulation  obtained  by  acid  or  rennet  is 
more  .solid  and  is  liarder  than  that  from  cow's  milk.  Sheep's  milk  is  similar  to  goat's 
milk,  but  has  a  higher  specific  gravity  and  contains  a  greater  amount  of  solids. 

Make's  milk  is  alkaline  and  contains  a  casein  -which  is  not  precipitated  by  acids  in 
lumps  or  solid  masses,  but,  like  the  casein  from  woman's  milk,  in  fine  flakes.  Thia 
ca.sein  is  only  incompletely  precipitated  l)y  rennet,  and  it  is  very  similar  also  in  other 
respects  to  the  casein  of  human  milk.  According  to  Beil.'»  the  casein  from  mare's  and 
cow's  milk  is  the  .same,  and  the  dillerent  behavior  of  the  two  varieties  of  milk  is  due  to 
different  amounts  of  salts  and  to  a  different  relation  between  the  ca,sein  and  the  albu- 
min. The  milk  of  the  ass  is  claimed  by  older  a\ilhorilies  to  be  similar  to  human  milk, 
hut  Schlossmann  finds  it  considerably  poorer  in  fat.  Reindeer  milk  characterizes 
itself,  according  to  "Wekenskiold,'  l)y  being  very  rich  in  fat,  144.6-197.3  p.  m.,  and 
casein,  80. 6-86.9  p.  m. 

'  Nilson,  1.  c. 

*  See  Sebelien,  Maly's  Jahresber.,  Bd.  18,  and  Tiemann,  Zeitschr.  f.  physiol.  Chem.» 
Bd.  25. 

2  See  Konig,  1.  c,  p.  313,  and  Nilson,  1.  c. 

*  Studien  liber  die  Eiwei.ssstoffe  des  Kumys  und  Kefirs.  St.  Petersburg,  1886. 
(Ricker.) 

*  Schlossmann,  Zeitschr.  f.  physiol.  Chem.,  Bd.  22  ;  Wcrenskiold,  Maly's  .Jahresber., 
Bd.  25. 


HUMAN  MILK.  397 

The  milk  of  carnivora  (tlie  bitcli  and  oit)  arc  acid  in  nactioii  and  very  ritii  in 
solids.  Thf  composiiion  of  the  inilli  of  tliese  aiiiinais  varies  very  much  with  the  com- 
jiosition  of  the  food. 

To  illustrate  the  composiiion  of  the  milk  of  other  animals  the  following  figures,  the 
compilation  of  KitNio,  are  given.  As  the  milk  of  each  kind  of  animals  may  have  a 
variable  composition,  these  ligines  should  only  be  ccjusidered  us  examples  of  the  com- 
position of  milk  of  various  kinds.' 

Milk  of  the  Water.         Solids.      Prnteids.      Fat.         Stipnr        Salts. 

Dog 754.4        245.6        99.1        95.7        bl.9        7.3 

Cat  816.3        183.7        90.8        33.3        49.1        5.8 

Goat S69.1         130.9        36.9        40.9        44.r,        8.6 

Sheep 835.0         165.0         57.4        61.4         39.6        6.6 

Cow 871.7        128.3        35.5        36.9        48.8        7.1 

Horse 900.6  99.4        18.9        10.9        66.5        3.1 

Ass .900.0         100.0        21.0         13.0        63.0         3.0 

Pig »2:!.7         167.3        60.9        64.4        40.4       10.6 

El.phant 678.5        321.5        30.9      195.7        88.4        6.5 

Dolphin 486.7        513.3         ....       437.6         ....        4.6 

Human  Milk. 

Womaa's  milk  is  amphoteric  in  reaction.  According  to  Coukant  its 
reaction  is  relatively  more  alkaline  than  cow's  milk,  but  has  nevertheless  a 
lower  absolnte  reaction  for  alkalinity  as  well  as  acidity.  Couraxt  found  be- 
tween the  tentii  day  and  tlie  fourteenth  month  after  confinement  practically 
constant  results.  The  alkalinity,  as  well  as  the  acidity,  was  a  little  lower  than 
in  childbed.     100  c.c.  of  the  milk  had  the  same  average  alkalinity  as  10.8 

X  .  X       .  . 

c.c.  "-  -  caustic  soda,  and  the  same  acidity  as  3.6  c.c.    -■  acid.     The  relation- 
10  '  "^  10 

ship  between  the  alkalinity  and  the  acidity  in  woman's  milk  was  as  3  :  1, 

and  in  cow's  milk  as  2.1  :  1. 

Human  milk  also  contains  fewer  fat-globules  than  cow's  milk,  but  they 
are  larger  in  size.  The  specific  gravity  of  woman's  milk  varies  between 
1036  and  1036,  generally  between  1028  and  1034.  The  specific  gravity  is 
highest  in  well-fed  and  lowest  in  poorly  fed  women. 

Tlie  fat  of  woman's  milk  has  been  investigated  by  Euppel.  It  forms  a 
yellowish-white  mass,  similar  to  ordinary  butter,  having  a  specific  gravity 
of  0.966  at  -f  15"  C.  It  melts  at  34.0°  and  solidifies  at  20.2°  C.  The 
following  fatty  acids  can  be  obtained  from  the  fat,  namely,  butyric,  caproic, 
capric,  myristic,  palmitic,  stearic,  and  oleic  acids.  The  fat  from  woman's 
milk  is,  according  to  Euppel  and  Laves,"  relatively  poor  in  volatile  fatty 
acids.  The  non-volatile  fatty  acids  consist  of  one  half  oleic  acid,  while 
among  the  solid  fatty  acids  myristic  and  palmitic  acids  are  found  to  a 
greater  extent  than  stearic  acid. 

The  essential  qualitative  difference  between  woman's  and  cow's  milk 
seems  to  lie  in  the  proteids  or  in  the  more  accurately  determined  casein. 

'  Details  in  regard  to  the  milk  of  different  animals  may  be  found  in  Proscher,  Zeit- 
schr.  f.  physiol.  Chem.,  Bd.  24. 

*  Kuppel,  Zeitschr.  f.  Biologic,  Bd.  31  ;  Laves,  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 


398  MILK. 

A  number  of  older  and  yoanger  investigators '  claim  that  the  casein  from 
woman's  milk  has  other  properties  than  that  from  cow's  milk.  The  essential 
differences  are  the  following:  The  casein  from  woman's  milk  is  precipitated 
with  greater  difficalty  with  acids  or  salts;  it  does  not  coagulate  regularly  in 
the  milk  after  the  addition  of  rennet;  it  may  be  precipitated  by  gastric 
juice,  but  dissolves  completely  and  easily  in  an  excess  of  the  same;  the 
casein  precipitate  produced  by  an  acid  is  more  easily  soluble  in  an  excess  of 
the  acid;  and  lastly,  the  clot  formed  from  the  casein  of  woman's  milk  does 
not  appear  in  such  large  and  coarse  masses  as  the  casein  from  cow's  inilk, 
but  is  more  loose  and  flocculent.  This  last-mentioned  fact  is  of  great  im- 
portance, since  it  explains  the  generally  admitted  easy  digestibility  of  the 
casein  from  woman's  milk.  The  question  as  to  whether  the  above-men- 
tioned differences  depend  on  a  decided  difference  in  the  two  caseins  or  only 
on  an  unequal  relationship  between  the  casein  and  the  salts  in  the  two- 
kinds  of  milk,  or  upon  other  circumstances,  has  been  recently  investi- 
gated. According  to  Szontagh*  the  casein  from  human  milk  does  not 
yield  any  psendonuclein  on  pepsin  digestion  and  hence  it  cannot  be  a 
nucleoalbumin.  Wroblewski  '  has  recently  arrived  at  the  same  results, 
and  also  found  that  the  two  caseins  had  a  different  composition.  He  found 
the  follQWing  for  the  composition  of  casein  from  woman's  milk:  C  52.24, 
H  7.32,  N  14.97,  P  0.68,  S  1.117,  0  23.06^.  Woman's  milk  also  contains 
lactalbumin,  besides  the  casein,  and  a  protein  substance,  very  rich  in  sulijhur 
(4.7^)  and  relatively  poor  in  carbon,  which  Wkoblewski  calls  opalisin. 
The  statements  as  to  the  occurrence  of  albumoses  and  peptone  are  disputed 
as  in  many  other  cases.  No  positive  proof  as  to  the  occurrence  of  albumoses 
and  peptone  in  fresh  milk  has  been  given. 

Even  after  those  differences  are  eliminated  which  depend  on  the  imper- 
fect analytical  methods  employed,  the  quantitative  composition  of  woman'' s 
milk  is  variable  to  such  an  extent  that  it  is  impossible  to  give  any 
average  results.  The  recent  analyses,  especially  those  made  on  a  large 
number  of  samples  by  Pfeiffer,  Adriakce,  Camerer  and  Soldner,'  have 


'  See  Biedert,  Untersuchungeu  iiber  die  cbeinischen  Uuterschiede  der  Meuschen-  und 
Kubiuilcli  (Stuttgart,  1884);  Langgaard,  Virchow's  Arch.,  Bd.  65;  Makris,  Studien 
ilbei-  die  Eiweisskorper  der  Frauen-  und  Kubmilcb.     luaug.-Diss.     Strassburg,  1876. 

2  Maly's  Jaiiresber.,  Bd.  22,  S.  168. 

'  "Beitrageznr  Kenutuisse  desFruueiikaseins"  (Iiuing.-Diss.,  Bern,  1894),  and  "Ein 
neiier  eiweissartiger  Bestandtheil  der  Milcli,"  Aiizciger  der  Akad.  d.  Wiss,  in  Krakau, 
1898. 

"  Pfeiffr-r,  Julirb.  f.  Kinderheilkiinde,  Ed.  20;  a'.so  Maly'.s  Jabresber.,  Bd.  13;  V. 
Adriance  and  J.  Adriance,  A  Clinical  R  port  of  tlie  Clieniicai  Examination,  etc.,  Arcbives 
of  Pediatrics,  1897  ;  Camerer  and  SiJldner,  Zcitsciir.  f.  Biologic,  Bdd.  33  and  36.  In  re- 
gard to  the  compcsition  of  woman'.i  nulk  see  also  Biol,  Maly'.s  Jaiiresber  ,  Bd.  4  ;  Cbris- 
tenn,  ibid.,  Bd.  7  ;  Mendes  de  Leon,  ibid.,  Bd.  12  ;  Gerber,  Bull.  soc.  Chim.,  Tome  23 ;. 
Tolmatscbeff,  Hoppe-Seyler's  Med.-chem.  Untersuch.,  S.  272. 


COMPOSITION  OF   WOMAN'S  MILK.  399 

positively  shown  that  woman's  milk  is  essentially  poorer  in  proteids  but 
richer  in  sugar  than  cow's  milk.  The  qnantity  of  proteid  varies  between 
10-20  p.  m.,  often  amounting  to  only  15-17  p.  m.  or  less,  and  is  dependent 
upon  the  length  of  lactation  (see  below).  The  quantity  of  fat  also  varies 
considerably^y  but  ordinarily  amounts  to  30-40  p.  m.  The  quantity  of  sugar 
should  not  be  below  50  p.  m.,  but  may  rise  to  even  80  p.  n).  We  may  consider 
about  00  p.  m.  as  an  average,  but  we  should  bear  in  mind  that  the  quantity 
of  sugar  is  also  dependent  upon  the  length  of  lactation,  as  it  increases  with 
duration.     The  quantity  of  mineral  bodies  varies  between  2  and  4  p.  m. 

The  most  essential  differences  between  woman's  and  cow's  milk  are  as 
follows,  from  a  quantitative  standpoint:  As  compared  with  the  quantity  of 
albumin,  the  qnantity  of  casein  is  not  only  absolutely  but  also  relatively, 
smaller  in  woman's  milk  than  in  cow's  milk,  while  the  latter  is  jioorer  in 
milk-sugar.  Human  milk  is  richer  in  lecithin  and  nucleon.  According  to 
"WiTTMAACK  cow's  milk  contains  0.566  p.  m.  nucleon,  and  woman's  milk 
1.24  p.  m.  Siegfried'  finds  that  the  nucleon  jihosphorus  amounts  to  60 
p.  m.  of  the  total  phosphorus  in  cow's  milk  and  415  p.  m.  in  woman's  milk, 
and  also  that  human  milk  contains  nearly  entirely  organic  combined  phos- 
phorus. Woman's  milk  is  poorer  in  mineral  bodies,  especially  lime,  and  it 
contains  only  one  sixth  of  the  quantity  of  lime  as  compared  with  cow's  milk. 
Human  milk  is  claimed  to  be  also  poorer  in  citric  acid  (Sciieibe'),  although 
this  is  not  an  essential  difference. 

In  regard  to  the  quantity  of  mineral  bodies  in  woman's  milk  the  analyses 
of  BuNGE  are  most  reliable.  lie  analyzed  the  milk  of  a  woman,  fourteen 
days  after  delivery,  whose  diet  contained  very  little  common  salt  for  four 
days  previous  to  the  analysis  (A),  and  again  three  days  later  after  a  daily 
addition  of  30  grms.  KaC'l  to  the  food  (B).  Bunge  found  the  following 
figures  in  1000  parts  of  the  milk: 

A  B 

K,0 0.780  0.703 

Na,0 0.232  0.257 

CaO «  328  0.343 

MgO  0.064  0.065 

Fe.,03 0.004  0.006 

PaOs 0.473  0.469 

CI 0.438  0.445 

The  relationship  of  the  two  bodies,  potassium  and  sodium,  to  each  other 
may,  according  to  Bunge,  vary  considerably  (1.3-4.4  equivalents  potash  to 
1  of  soda).  By  the  addition  of  salt  to  the  food  the  quantity  of  sodium  and 
chlorine  in  the  milk  increases,  while  the  quantity  of  potassium  decreases. 
De  Lange  '  found  more  Na  than  K  in  the  milk  at  the  beginning  of 
lactation. 

>  Wittnuiack,  Zeitscbr.'f.  pbysiol.  Cheui.,  Bd.  22;  Siegfried,  ibid.,  Bd.  22. 

»  Maly's  Jahresber.,  Bd.  21. 

^  Bunge,  Zeitscbr.  f.  Biologic,  Bd.  10  ;  De  Lange,  Maly's  Jahresber.,  Bd.  27. 


400  MILK. 

The  gases  of  woman's  milk  have  been  investigated  by  Kulz.'  He  found 
1.07-1.44  c.c.  oxygen,  2.35-2.87  c.c.  carbon  dioxide,  and  3.37-3.81  c.c. 
nitrogen  in  100  c.c.  milk. 

The  proper  treatment  of  cosv's  milk  by  diluting  with  water  and  by 
certain  additions  in  order  to  render  it  a  proper  substitute  for  woman's  milk 
in  the  nourishment  of  babes  cannot  be  determined  before  the  difference  in 
the  albuminous  bodies  of  these  two  kinds  of  milk  has  been  completely 
studied. 

The  colostrum  has  a  higher  specific  gravity,  1.040-1.060,  a  greater 
quantity  of  coagulable  proteids,  and  a  deeper  yellow  color  than  ordinary 
woman's  milk.  Even  a  few  days  after  delivery  the  color  becomes  less 
yellow,  the  quantity  of  albumin  less,  and  the  number  of  colostrum-corpuscles 
diminishes. 

We  have  the  older  analyses  of  Clemm  '  and  the  recent  investigations  of 
Pfeiffer,  V  and  J.  Adriaistce,  Camerer  and  Soldjster  on  the  changes  in 
the  composition  of  milk  after  delivery.  It  follows,  as  a  unanimous  result 
from  these  investigations,  that  the  quantity  of  proteid,  which  amounts  to 
more  the  first  two  days,  sometimes  amounting  to  more  than  30  p.  m.  at 
first,  rather  quickly  and  then  more  gradually  diminishes  as  long  as  the  lacta- 
tion continues,  so  that  in  the  third  week  it  amounts  to  about  10-18  p.  m. 
Like  the  protein  substances  so  do  the  mineral  bodies  gradually  decrease. 
The  quantity  of  fat  shows  no  regular  or  constant  variation  during  lactation, 
while  the  lactose,  especially  according  to  the  observations  of  V.  and 
J.  Adeiaxce  (120  analyses),  increases  rather  quickly  the  first  days  and  then 
only  slowly  until  the  end  of  lactation.  The  analyses  of  Pfeiffer,  Camerer 
and  SoLDNER  also  show  an  increase  in  the  quantity  of  milk-sugar. 

Tbe  two  mammaiy  glands  of  the  same  woman  may  yield  somewhat  different  milk, 
as  slitnvu  by  Soukdat  and  later  by  Brunneh.^  Likewise  the  different  portions  of  milk 
from  the  same  milking  may  have  varying  composition.  The  first  portions  are  always 
poorer  in  fut. 

According  to  l'Heritieu,  Vernois  and  Becquehel  the  milk  of  blonds  contains 
less  casein  than  that  of  brunettes,  a  difference  which  Tolmatscheff"' could  not  sub- 
stanii;ile.  Women  of  delicate  constitutions  yield  a  miik  richer  in  solids,  especially  in 
casein,  tiiaii  women  with  strong  constitutions  (V.  and  B.)- 

A<c<>rding  to  Veknois  and  13ecqueri;i.,  the  age  of  the  woman  has  an  effect  on  the 
compositiuu  of  the  milk,  so  that  we  find  a  greater  quantity  of  proteidsand  fat  in  women 
15-20  years  old,  and  a  smaller  quaniiiy  of  sugar.  The  smallest  quantity  of  proteids  and 
the  greatest  quantity  of  sugar  are  found  at  20  or  from  25-BO  years  of  age.  According  to 
V.  and  B.,  the  milk  with  the  first-born  is  richer  in  water — with  a  proportionate  diminu- 
tion of  casein,  sugar,  and  fat — than  after  several  deliveries. 

The  influence  of  menstruation  seems  to  slightly  diminish  the  milk-sugar  and  to  con- 
f^iderably  increase  the  fat  and  casein  (V.  and  B.). 


'  Zeitsdir.  f.  Biologie.  Bd.  32. 

«  See  Hoppe-Seyler,  Physiol.  Chem.,  S.  734. 

"  Sourdat,  Conipt.  rend..  Tome  71  ;  Brunner,  Pflliger's  Arch.,  Bd.  7. 

■»  I'Heritier,  cited  from  Hoppe-Scyler.  Physiol.  Chem.,  S.  738  ;  Vernois  and  Bcc- 
querel,  Du  lait  chez  la  femme  dans  I'etat  de  sante,  etc.  (Paris,  1853) ;  Tolmatscheff, 
Hoppe-Seyler,  Med. -chem.  Untersuch.,  S.  272. 


ASH  OF  MILK  AND  ANIMALS.  401 

Witch's  milk  is  the  stciclioii  of  tlio  niaiiimar}'  glands  of  n('\v-l)orn  fhildrni  of  lioth 
sexes  iiimieilial«'lv  after  hiilh.  This  secretion  lias  from  u  qiialitiitive  sliiruiiioinl  the  sume 
constilulioii  as  milk,  but  may  show  imporlaiil  difTeienees  and  vaiialions  fiom  a  quanii- 
iHtive  i)oinl  of  view  .  St'nLosKiiKUoi-;K  mid  IIaikk,  Giiu-kk  and  Qi'Kvknni'.  and  v.  Gk.v- 
SKU  '  iiave  made  analyses  of  this  milk  juid  give  the  following  rcsidts  :  10.r)-28  p.  ni.  pro- 
teids,  8  2-14.ti  p.  m.  fat,  and  9-GO  p.  m.  sugar. 

As  milk  IS  the  only  form  of  iiourislimeiit  diiriii^^  a  certain  period  of  tlie 

life  of  man  and  mammals,  it  must  contain  all  the  nutritious  bodies  necessary 

for  life.     This  fact  is  shown  by  the  milk-containing  representatives  of  the 

three  chief  groups  of  organic  nutritive  substances,  proteids,  carbohydrates, 

and  fat;  and  all  milk  seems  to  contain  without  doubt  also  some  lecithin  and 

nucleoQ.     The  mineral  bodies  in  milk  must  also  occur  in  proper  proportions, 

and  on  this  point  the  experiments  of  Bun(;t-:  on  dogs  are  of  special  interest. 

lie  found  that  the  mineral   bodies  of  the  milk  occur  iti  about  the  same 

relative  proportion  as  cliey  do  in  the  body  of  the  sucking  animiil.     Buxge' 

found  in  1000  parts  of  the  ash  the  following  results  (A  represents  results 

from  the  new-born  dog,  and  B  the  milk  from  the  bitch) : 

A  B 

K,0 114.2  149.8 

Na,0 106.4  88.0 

CaO 295.2  272.4 

MgO 18.2  15.4 

Fe.03 ".3  1.2 

P,06 394.2  342.2 

CI B3.5  169.0 

BuNGE  explains  the  fact  that  the  milk-ash  is  richer  in  potash  and  poorer 
in  soda  than  the  new-born  animal  by  saying  that  in  the  growing  animal  the 
ash  of  the  muscles  rich  in  potash  relatively  increases  and  the  cartilage  rich 
in  soda  relatively  decreases.  In  regard  to  the  amount  of  iron  we  find  an 
nnexpected  condition,  the  ash  of  the  new-born  animal  containing  six  times 
as  much  as  the  milk-ash.  This  condition  Buxge  explains  by  the  fact 
founded  on  his  and  Zalesky's  experiments,  that  the  quantity  of  iron  in 
the  entire  organism  is  highest  at  birth.  Even  at  its  birth,  therefore,  the 
new-born  animal  has  a  supply  of  iron  for  the  growth  of  its  organs.  Abder- 
halden's'  recent  researches  show  in  a  very  striking  manner  the  corre- 
spondence of  the  ash  of  the  sucking  animal  (rabbit)  to  the  corresponding 
milk.  He  has  also  further  given  very  interesting  proof  as  to  the  relationship 
of  the  rapidity  of  growth  of  the  animal  to  the  quantity  of  proteids,  lime, 
and  phosphoric  acid  in  the  milk. 

The  ([uantity  of  mineral  bodies 'in  the  milk,  and  especially  the  quantity 
of   lime   and   phosphoric   acid,   as  shown   by   Bunge   and  Proscher  and 

»  Schlossberger  and  Han ff,  Aunal.  d.  Chem.  u.  Phaim.,  Bd.  96;  Gubler  and  Que- 
venne,  cited  from  Hoppe-Seyler's  Physiol.  Chem.,  S   723;  v.  Genser,  ibid. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  13,  S.  399.  The  recent  investigations  of  De  Lange 
(1.  c.)  on  the  quantity  of  ash  in  human  milk  and  new-born  child  show  that  in  human 
beings  the  conditions  are  different  than  in  dogs. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 


402  MILK. 

Pages,'  stand  in  close  relationsliip  to  the  rapidity  of  growth,  because  the 
quantity  of  these  mineral  constituents  in  the  milk  is  greater  in  animals 
which  grow  and  develop  quickly  than  in  those  which  grow  only  slowly. 
According  to  Proscher  a  similar  relationship  exists  between  the  quantity 
of  proteids  and  rapidity  of  growth. 

The  -influefice  of  the  food  on  the  composition  of  the  milk  is  of  interest 
from  many  points  of  view  and  has  been  the  subject  of  many  investigations. 
Prom  these  investigations  we  learn  that  in  human  beings  as  well  as  in 
animals  an  insufficient  diet  decreases  the  quantity  of  milk  and  the  quantity 
of  solids  while  abundant  food  increases  both.  From  the  observations 
of  Decaisne"  on  nursing  women  during  the  siege  of  Paris  in  1871,  the 
quantity  of  casein,  fat,  sugar,  and  salts,  but  especially  the  fat,  was  found 
to  decrease  with  insufficient  food,  while  the  quantity  of  lactalbumin  was 
found  to  be  somewhat  increased.  Food  rich  in  proteids  increases  the 
quantity  of  milk,  and  also  the  solids  contained,  especially  the  fat.  The 
quantity  of  sugar  in  woman's  milk  is  found  by  certain  investigators  to  be 
increased  after  food  rich  in  proteids,  while  others  claim  it  is  diminished. 
Food  rich  in  fat  may,  as  the  recent  researches  of  Soxhlet'  have  shown, 
cause  a  marked  increase  in  the  fat  of  the  milk  when  the  fat  partaken  is  in  a 
readily  digestible  and  assimilable  form.  The  presence  of  large  quantities  of 
carbohydrates  in  the  food  seems  to  cause  no  constant,  direct  action  on  the 
quantity  of  the  milk-constituents.*  In  carnivora,  as  shown  by  Ssubotin,^ 
the  secretion  of  milk-sugar  proceeds  uninterruptedly  on  a  diet  consisting 
exclusively  of  lean  meat.  "Watery  food  gives  a  milk  containing  an  excess  of 
water  and  having  little  value.  In  the  milk  from  cows  which  were  fed  on 
distillers'  grain  Commaille  °  found  906.5  p.  m.  water,  26.4  p.  m.  casein, 
4.3  p.  m.  albumin,  18.2  p.  m.  fat,  and  33.8  p.  m.  sugar.  Such  milk  has 
sometimes  a  peculiar  sharp  after- taste.' 

Cliemistry  of  Milk-secretion.  That  the  actually  dissolved  constit- 
uents occurring  in  milk  pass  into  the  secretion  not  alone  by  filtration  or 
diffusion,  but  more  likely  are  secreted  by  a  specific  secretory  activity  of  the 

'Proscher,  Zeltschr.  f.  physiol.  Cliera,,  Bd.  24;  Pagfis,  Arch,  de  Physiol.  (5), 
Tome  7. 

'  Cited  from  Hoppe-Seyler,  1.  c,  p.  739. 

'  See  Maly's  Jahresber,,  Bd.  26. 

''  In  regard  to  the  literature  ou  tlie  action  of  various  foods  on  woman's  milk  see 
Zalesky,  "  Ueber  die  Einwirkung  der  Nahrung  auf  die  Zusammensetzung  und  Nahr- 
haftigkeit  der  Frauenmilch,"  Berlin,  klin.  Wochenschr.,  1888,  which  also  contains  the 
literature  on  the  importance  of  the  food  on  the  composition  of  otlier  kinds  of  milk. 
In  regard  to  the  extensive  literature  on  the  inlluence  of  various  foods  on  the  milk  pro- 
duction of  animals,  see  KOnig,  Chem.  d.  monschl.  Nahrungs-  und  Genussmittel,  3.  Aufl.,. 
Bd.  1.  S.  298. 

'  Centralbl.  f.  d.  med.  Wissensch.,  1866,  S.  337. 

6  Cited  from  Konig,  Bd.  2,  S.  235. 

'  See  Beck,  Maly's  Jahresber.,  Bd.  25,  S.  223. 


CHEMISTRY  OF  MILK  SECltKTION.  40:3 

glandular  elements,  is  shown  by  the  fact  that  milk-sugar,  which  is  not  found 
in  the  blood,  is  to  all  appearances  formed  in  the  glands  themselves.  A 
further  proof  lies  in  the  fact  that  the  lactalbumin  is  not  identical  with 
seralbumin;  and  lastly,  as  Bunge  '  has  shown,  the  mineral  bodies  secreted 
by  the  milk  -are  in  <iuite  different  proportions  from  those  in  the  blood- 
eerum. 

Little  is  known  in  regard  to  the  formation  and  secretion  of  the  specific 
constituents  of  milk.  The  older  theory,  that  the  casein  was  produced  from 
the  lactalbumin  by  the  action  of  an  enzyme,  is  incorrect  and  originated 
probably  from  mistaking  an  alkali-albuminate  for  casein.  Better  founded 
is  the  statement  that  the  casein  originates  from  the  protoplasm  of  the 
gland-cells,  which  seem  to  consist  of  casein  or  a  substance  related  to  it. 
The  previously  mentioned  (page  385)  nucleoproteid  of  the  gland-cells 
appears  to  be  related  to  casein,  and  it  may  jiossibly  form  its  mother-sub- 
stance. There  does  not  seem  to  be  any  doubt  that  the  protoplasm  of  the 
cells  takes  part  in  the  secretion  in  such  a  manner  that  it  becomes  itself  a 
constituent  of  the  secretion,  and  this  also  agrees  with  Heidenhaix's  ""  views. 
According  to  Bascii's  ^  researches  the  casein  is  formed  in  the  mammary 
gland  by  the  nucleic  acid  of  the  nucleus  set  free,  uniting  intra-alveolar  with 
the  transudated  serum,  forming  a  nucleoalbumin,  the  casein;  but  strong 
objections  can  be  presented  against  such  a  view. 

That  the  milk-fat  is  produced  by  a  formation  of  fat  in  the  protoplasm, 
and  that  the  fat-globules  are  set  free  by  their  destruction,  is  a  generally 
admitted  opinion,  which,  however,  does  not  exclude  the  possibility  that  the 
fat  is  in  part  taken  up  by  the  glands  from  the  blood  and  eliminated  with 
its  secretion.  That  the  fats  of  the  food  can  pass  into  the  milk  follows  from 
the  investigations  of  Wixternitz,'  as  he  has  been  able  to  detect  the  passage 
of  iodized  fats  in  the  milk.  The  observations  of  Spampani  and  Daddi  '  of 
the  passage  of  sesame-oil  into  the  milk  also  prove  this  fact.  A  formation 
of  fat  from  carbohydrates  in  the  animal  organism  is  at  the  present  day  con- 
sidered as  positively  proved,  and  it  is  likewise  possible  that  the  milk-glands 
also  produce  fats  from  the  carbohydrates  brought  to  them  by  the  blood.  It 
is  a  well-known  fact  that  an  animal  gives  off  for  a  long  time,  daily,  consider- 
ably more  fat  in  the  milk  than  it  receives  as  food,  and  this  proves  that  at  least 
a  part  of  the  fat  secreted  by  the  milk  is  produced  from  proteids  or  carbo- 
hydrates, or  perhaps  from  both.  The  question  as  to  how  far  this  fat  is 
produced  directly  in  the  milk-glands,  or  from  other  organs  and  tissues,  and 
brought  to  the  gland  by  means  of  the  blood,  cannot  be  decided. 

The  origin   of   milk-sugar  is  not  known.      Muntz   calls  attention   to 

'  Lehrbuch  d.  physiol.  und  patliol.  Chem.,  3.  Aufl.,  S.  93. 
'  Hermann's  Ilaiuihiicli,  Bd.  5,  Abtlil.  1.  S.  380. 
'  Jalubucli  f.  Kinderheilkundc,  1898. 
■•  Zeitsclir.  f.  pliysiol.  Chem.,  Bd.  24. 
»  See  Maly's  Jaliresber.,  Bd.  26,  S.  298. 


404  MILK. 

the  fact  that  a  number  of  very  widely  diffused  bodies  in  the  vegetable 
kingdom — vegetable  mucilage,  gums,  pectin  bodies — yield  galactose  as 
products  of  decomposition,  and  he  believes,  therefore,  that  milk-sugar 
may  be  formed  in  herbivora  by  a  synthesis  from  dextrose  and  galactose. 
This  origin  of  milk-sugar  does  not  apply  to  carnivora,  as  they  produce 
milk-sugar  when  fed  on  food  consisting  entirely  of  lean  meat.  The  obser- 
vations of  Bert  and  Thierfelder  '  that  a  mother-substance  of  the  milk- 
sugar,  a  saccharogen,  occurs  in  the  glands  cannot  give  further  explanation  as 
to  the  formation  of  milk-sugar,  as  the  nature  of  this  mother-substance  is  still 
unknown.  The  question  whether  the  above-mentioned  (page  385)  proteid, 
which  yields  a  reducing  substance  when  boiled  with  dilute  acids,  has  any- 
thing to  do  with  the  formation  of  milk-sugar  cannot  be  answered  until 
further  and  more  thorough  investigations  have  been  made  of  this  subject. 

The  passage  of  foreign  substances  into  the  milk  stands  in  close  connec- 
tion with  the  chemical  processes  of  milk-secretion. 

It  is  a  well-known  fact  that  milk  acquires  a  foreign  taste  from  the  food 
of  the  animal,  which  is  in  itself  a  proof  that  foreign  bodies  pass  into  the 
milk.  This  fact  becomes  of  special  importance  in  reference  to  such  injurious 
substances  as  may  be  introduced  into  the  organism  of  the  nursing  child  by 
means  of  the  milk. 

Among  these  substances  may  be  mentioned  opium  and  morphine,  which 
after  large  doses  pass  into  the  milk  and  act  on  the  child.  Alcohol  may  also 
pass  into  the  milk,  but  probably  not  in  such  quantities  as  to  have  any  direct 
action  on  the  nursing  child."  Alcohol  is  claimed  to  have  been  detected  in 
the  milk  after  feeding  cows  with  brewer's  grains. 

Among  inorganic  bodies,  iodine,  arsenic,  bismuth,  antimony,  zinc,  lead, 
mercury,  and  iron  have  been  found  in  milk.  In  icterus  neither  bile-acids 
nor  bile-pigments  pass  into  the  milk. 

Under  disesised  conditions  no  constant  change  has  been  found  in  woman's  milk.  In 
isolated  cases  Schlossbeugek,  Joly  and  Filiiol^  have  ol)served  indeed  a  markedly  ab- 
normal composition,  but  no  positive  conclusion  can  be  derived  therefrom. 

The  changes  in  cow's  milk  in  disease  have  been  lillle  studied.  In  tubei'culosisof  the 
udder  Storcii''  found  Uiljereule  bacilli  in  the  milk,  and  he  also  found  that  the  milk  be- 
came more  and  more  diluted,  during  the  disease,  with  a  serous  liquid  similar  to  blood- 
serum,  so  that  the  glands  finally,  instead  of  yielding  milk,  gave  only  blood-serum  or  a 
serous  fluid.  Husson  '  found  that  milk  from  murrain  cows  contained  more  proteids 
but  considerably  less  fat  and  (in    evere  cases)  h  ss  sugar  than  normal  milk. 

Tlie  milk  may  be  blue  or  red  in  color,  due  to  the  development  of  micro-organisms. 

The  formation  of  concrements  in  the  exit-passages  of  the  cow's  udder  is  often  ob- 
served. They  consist  chiefly  of  calcium  carbonate,  or  of  carbonate  and  phosphate  with 
only  a  small  amount  of  organic  substances. 

'  Muntz,  Compt.  rend.,  Tome  102  ;  Bert  and  Thierfelder,  foot-notes  1  and  2,  page  385. 
'  See  Klingemann,  Virchow's  Arch.,  Bd.  126. 

*  Schlossberger,  Annal.  d.  Chem.  u.  Pliarm.,  Bd.  96;  Joly  and  Filhol,  cited  from 
'Gurup-Besanez,  Lehrb.,  4.  Aufl.,  S.  438. 

'•  See  Bang,  Om  Tubcrkulose  i  Koens  Yver  og  om  tuberkulos  Millk.  Nord.  med.  Ar- 
klv,  Bd.  16,  and  also  Maly'sJahresber.,  Bd.  14,  S.  170  ;  Storch,  Maly's  Jahresber.,  Bd.  14. 

*  Compt.  rend.,  Tome  73. 


CHAPTER   XV. 
URINE. 

Urine  is  the  mosb  important  excretion  of  tlie  animal  organism ;  it  is  tlie 
means  of  eliminating  the  nitrogenous  metabolic  products,  also  tlie  water  and 
the  soluble  mineral  substances;  and  in  many  cases  it  furnishes  important  data 
relative  to  the  metabolism,  quantitatively  by  its  variation,  and  qualitatively 
by  the  appearance  of  foreign  bodies  in  the  excretion.  Moreover  in  many 
cases  we  are  able  from  tlie  chemical  or  morphological  constituents  which  the 
urine  abstracts  from  the  kidneys,  ureters,  bladder,  and  urethra  to  judge  of 
the  condition  of  these  organs;  and  lastly,  urinary  analysis  affords  an  excel- 
lent means  of  deciding  the  question  how  certain  medicines  or  other  foreign 
substances  introduced  into  the  organism  are  absorbed  and  chemically 
changed.  In  this  respect  especially  urinary  analysis  has  furnished  very 
important  particulars  in  regard  to  the  nature  of  the  chemical  processes 
taking  place  within  the  organism,  and  it  is  therefore  not  only  an  important 
aid  in  diagnosis  to  the  physician,  but  it  is  also  of  the  greatest  imjiortance 
to  the  toxicologist  and  the  physiological  chemist. 

In  studying  the  secretions  and  excretions  the  relationship  must  be  souglii^. 
between  the  chemical  structure  of  the  secreting  organ  and  tlie  chemical 
composition  of  its  secreted  products.  Investigations  with  respect  to  the: 
kidneys  and  the  urine  have  led  to  very  few  results  from  this  standpoint.. 
Although  the  anatomical  relation  of  the  kidneys  has  been  carefully  studied, 
their  chemical  composition  has  not  been  the  subject  of  thorough  analytical 
research.  In  cases  in  which  a  chemical  investigation  of  the  kidneys  has 
been  undertaken,  it  has  only  been  in  general  of  the  organ  as  such,  and  not 
of  the  different  anatomical  parts.  An  enumeration  of  the  chemical  con- 
stituents of  the  kidneys  known  at  the  present  time  can,  therefore,  have  onlf 
a  secondary  value. 

In  the  kidneys  we  find  albuminous  bodies  of  different  kinds.  According 
to  IIallihiktox  the  kidneys  do  not  contain  any  albumin,  but  onlv  a 
glohdin  and  a  nuchoproteid.  The  globulin  coagulates  at  about  52°  C,  and 
the  nucleoproteid  contains  0.37^  phosphorus.  According  to  L.  Lieber- 
MAXN  the  kidneys  contain  a  lecithaJMimin,  and  he  ascribes  to  this  body  a 
special  importance  in  the  secretion  of  acid  urines.  The  kidnevs  also 
contain,  according  to  Lonnberg,  a  mucin-like  substance.     This  substance 

405 


406  URINE. 

jields  a  reducing  body  on  boiling  with  acids  and  belongs  chiefly  to  the 
papillae,  and  is,  according  to  Lonnberg,  a  nucleoalbumin  (nucleoproteid '?). 
The  cortical  substance  is  richer  in  another  nucleoalbumin  (aucleoproteid) 
unlike  mucin.  It  has  not  been  decided  what  relationship  this  last  sub- 
stance bears  to  Halliburton's  nucleoproteid.  According  to  Morker  ' 
cliondroitin  sulphuric  acid  occurs  as  traces. 

Fat  occurs  only  in  very  small  amounts  in  the  cells  of  the  tortuous 
urinary  passages.  Among  the  extractive  bodies  of  the  kidneys  we  find 
xatitJmi  bodies,  also  urea,  uric  acid  (traces),  glycogen,  leucin,  inosit,  taurin, 
and  cystin  (in  ox-kidneys).  The  quantitative  analyses  of  the  kidneys  thus 
far  made  possess  little  interest.  Oidtmank  ^  found  810.94  p.  m.  water, 
179.16  p.  m.  organic  and  0.99  p.  m.  inorganic  substance  in  the  kidney  of 
an  old  woman. 

The  fluid  collected  under  pathological  conditions,  as  in  hydronephrosis,  is  thin  with 
a  variable  but  generally  low  specific  gravity.  Usually  it  is  straw-yellow  or  paler  in  color, 
and  sometimes  colorless.  Most  frequently  it  is  clear,  or  only  faintly  cloudy  from  white 
blood-corpuscles  and  epithelium-cells;  in  a  few  cases  it  is  so  rich  in  form-elements  that 
it  appears  like  pus.  Proteid  occurs  generally,  in  small  amounts;  occasionally  it  is  entirely 
absent,  but  in  a  few  rare  cases  the  amount  is  nearly  as  lai-ge  as  in  the  blood-serum. 
Urea  occurs  sometimes  in  considerable  amounts  when  the  parenchyma  of  the  kidneys  is 
only  in  part  atrophied  ;  in  complete  atrophy  the  urea  may  be  entirely  absent. 


I.  Physical  Properties  of  Urine. 

Consistency,  Transparency,  Odor,  and  Taste  of  "Urine.  Under  physio- 
logical conditions  urine  is  a  thin  liquid  and  gives,  when  shaken  with  air,  a 
froth  which  quickly  subsides.  Human  urine  or  urine  from  carnivora,  which 
is  habitually  acid,  appears  clear  and  transparent,  often  faintly  fluorescent, 
immediately  after  voiding.  When  allowed  to  stand  for  a  little  while  human 
urine  shows  a  light  cloud  {nubecula)  which  consists  of  the  so-called 
*'  mucus  "  and  generally  also  contains  a  few  epithelium-cells,  mucus-corpus- 
cles, and  urate-granules.  The  presence  of  a  larger  quantity  of  urates 
renders  the  urine  cloudy,  and  a  clay-yellow,  yellowish-brown,  rose-colored, 
or  often  brick-red  precipitate  {sedimentmn  lateritium)  settles  on  cooling, 
because  of  the  greater  insolubility  of  the  urates  at  the  ordinary  temperature 
than  at  the  temperature  of  the  body.  This  cloudiness  disappears  on  gently 
warming.  In  new-born  infants  the  cloudiness  of  the  urine  during  the  first 
4-5  days  is  due  to  epithelium,  mucus-corpuscles,  uric  acid,  and  urates. 
The  urine  of  herbivora,  which  is  habitually  neutral  or  alkaline  in  reaction, 
is  very  cloudy  on  account  of  tlie  carbonates  of  the  alkaline  earths  present. 
Human  urine  may  sometimes  be  alkaline  under  physiological  conditions. 
In  this  case  it  is  made  cloudy  by  the  earthy  phosphates,  and  this  cloudiness 

'Halliburton,  Journ.  of  Physiol.,  Vol.  13,  Suppl.,  and  Vol.  18;  Liebermann, 
Pflilger's  Arch.,  Bdd.  50  and  54;  Lonnberg,  see  Maly's  Jahresber.,  Bd.  20;  Morner, 
Skand.  Arch.  f.  Physiol.,  Bd.  6. 

'  Cited  from  v.  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  732. 


PHYSICAL  PROPERTIES  OF  URINE.  407 

does  not  disappear  on  warming,  dillering  in  this  respect  from  the  sedimen- 
tum  latcritium.  Urine  has  a  salty  and  faintly  bitter  taste  produced  by 
sodium  chloride  and  urea.  The  odor  of  urine  is  peculiarly  aromatic ;  the 
bodies  which  produce  this  odor  are  unknown. 

The  color  of  urine  is  normally  pale  yellow  when  the  specific  gravity  is 
1.020.  The  color  otherwise  depends  on  the  concentration  of  the  urine  and 
varies  from  pale  straw-yellow,  when  the  urine  contains  small  amounts  of 
solids,  to  a  dark  reddish  yellow  or  reddish  brown  in  stronger  concentration. 
As  a  rule  the  intensity  of  the  color  corresponds  to  the  concentration,  but 
under  pathological  conditions  exceptions  occur,  and  such  an  excejition  is 
found  in  diabetic  urine,  which  contains  a  large  amount  of  solids  and  has  a 
high  specific  gravity  and  a  pale  yellow  color. 

The  reaction  of  urine  depends  essentially  upon  the  composition  of  the 
food.  The  carnivora  void  an  acid,  the  herbivora,  as  a  rule,  a  neutral  or 
alkaline,  urine.  If  a  carnivora  is  put  on  a  vegetable  diet,  its  urine  may 
become  less  acid  or  neutral,  while  the  reverse  occurs  when  an  herbivora  is 
starved,  that  is,  when  it  lives  upon  its  own  flesh,  as  then  the  urine  voided  is 
acid. 

The  urine  of  a  healthy  man  on  a  mixed  diet  has  an  acid  reacfion,  and 
the  sum  of  the  acid  equivalents  is  greater  than  the  sum  of  the  base  equiva- 
lents. This  depends  on  the  fact  that  in  the  physiological  combustion  of 
neutral  substances  (proteids  and  others)  within  the  organism  acids  are  pro- 
duced, chiefly  sulphuric  acid,  but  also  phosphoric  and  organic  acids,  such  as 
hippuric,  uric,  and  oxalic  acid,  aromatic  oxyacids,  and  others.  From  this  it 
follows  that  the  acid  reaction  is  not  due  to  one  acid  alone.  "We  do  not  know 
to  what  extent  any  one  acid  takes  part  in  the  acid  reaction;  but  it  is 
generally  considered  that  the  acid  reaction  of  human  urine  is  caused  by 
di-acid  phosphate.  The  quantity  of  acid-reacting  bodies  or  combinations 
eliminated  by  the  urine  in  24  hours,  when  calculated  as  oxalic  acid  or 
hydrochloric  acid,  is  respectively  2-4  and  1.15-2.. 3  grms. 

The  composition  of  the  food  is  not  the  only  influence  which  afl'ects  the 
degree  of  acidity  of  human  urine.  For  example,  after  taking  food,  at  the 
beginning  of  digestion,  when  a  larger  amount  of  gastric  juice  containing 
hydrochloric  acid  is  secreted,  the  urine  may  be  neutral  or  even  alkaline.' 
The  statements  of  various  investigators  are  rather  contradictory  in  regard 
to  the  time  of  the  appearance  of  the  maximum  and  minimum  of  the  acidity, 
which  may  in  part  be  explained  by  the  different  individuality  and  different 
conditions  of  life  of  the  persons  investigated.  It  has  not  infrequently  been 
observed  that  perfectly  healthy  persons  in  the  morning  void  a  neutral  or 
alkaline  urine  which  is  cloudy  from  earthy  phosphates.  The  effect  of 
muscular  activity  on  the  acidity  of  urine  has  not  been  positively  determined. 

'  Contradictory  statements  are  found  in  Linossier,  Mal.v's  Jabrcsber.,  Bd.  27. 


408  URINE. 

According  to  Hoffmann,  Eingstedt,  Oddi  and  Tarulli  muscular  work 
raises  the  degree  of  acidity,  but  Aducco  '  claims  that  it  decreases  it. 
Abundant  perspiration  reduces  the  acidity  (Hoffmann). 

In  man  and  carnivora  it  seems  that  the  degree  of  acidity  of  the  urine 
cannot  be  increased  above  a  certain  point,  even  though  mineral  acids  or 
organic  acids  which  are  burnt  up  with  difficulty  are  taken  in  large  quantities, 
"When  the  supply  of  carbonates  of  the  fixed  alkalies  stored  up  in  the 
organism  for  this  piirpose  is  not  sufficient  to  combine  with  the  excess  of 
acid,  then  ammonia  is  split  from  the  proteids  or  their  decomposition 
products,  and  the  excess  of  acid  combines  therewith,  forming  ammonium 
salts  which  pass  into  the  urine.  In  herbivora  such  a  combination  of  the 
excess  of  acid  with  ammonia  does  not  seem  to  take  place,  or  not  to  the  same 
extent,'  and  therefore  herbivora  soon  die  when  acids  are  given.  Neverthe- 
less the  degree  of  acidity  of  human  urine  may  be  easily  diminished  so  that 
the  reaction  is  neutral  or  alkaline.  This  occurs  after  the  taking  of  car- 
bonates of  the  fixed  alkalies  or  of  such  alkali  salts  of  vegetable  acids — 
tartaric-acid,  citric-acid,  and  malic-acid  salts — as  are  easily  burnt  into 
carbonates  in  the  organism.  Under  pathological  conditions,  as  in  the 
absorption  of  alkaline  transudations,  the  urine  may  become  alkaline. 

Th&  degree  of  acidity  cannot  be  determined  by  the  ordinary  acidimetric 
process,  since  the  urine  contains  di-hydrogen  phosphate,  MH^PO^,  besides 
hydrogen  di-phosphate,  M^HPO,.  In  the  titration  the  di-hydrogen  phos- 
phate is  changed  gradually  into  M,HPO^,  and  we  obtain  at  a  certain  point 
a  mixture  of  the  two  phosphastes  in  variable  proportions,  which  mixture  is 
not  neutral  but  amphoteric.  As  we  consider  the  quantity  of  phosphoric 
acid  as  di-hydrogen  phosphate  as  a  measure  of  the  acidity  of  the  urine,  the 
determination  of  the  acidity  and  the  determination  of  di-hydrogen  phos- 
phate go  hand  in  hand.  The  methods  resorted  to  will  be  described  in 
connection  with  the  estimation  of  the  total  phosphoric  acid. 

A  urine  with  an  alkaline  reaction  caused  by  fixed  alkalies  has  a  very 
different  diagnostic  value  from  one  whose  alkaline  reaction  is  caused  by  the 
presence  of  ammonium  carbonate.  In  the  latter  case  we  have  to  deal  with 
a  decomposition  of  the  urea  of  the  urine  by  the  action  of  micro-organisms. 

If  we  wish  to  determine  whether  the  alkaline  reaction  of  the  urine  is 
due  to  ammonia  or  fixed  alkalies,  we  dip  a  piece  of  red  litmus-paper  into 
the  urine  and  allow  it  to  dry  exposed  to  the  air  or  to  a  gentle  heat.  If  the 
alkaline  reaction  is  due  to  ammonia,  the  paper  becomes  red  again;  but  if  it 
is  caused  by  fixed  alkalies,  it  remains  blue. 

The  specific  gravity  of  urine,  which  is  dependent  upon  the  relationship 
existing  between  the  quantity  of  water  secreted  and  the  solid  urinary  con- 
stituents, especially  the  urea  and  sodium  chloride,  may  vary  considerably, 
but  is  generally  1.017-1.020.     After  drinking  large  quantities  of  water  it 

'  Hoffmann,  see  Maly's  Jabresber.,  Bd.  14,  S.  313  ;  Ringstedt,  iUd.,  Bd.  30,  S.  196  ; 
Oddi  and  Tarulli,  ihid.,  Bd.  24  ;  Aducco,  ibid.,  Bd.  17. 
^  See  Wiiitorberg,  Zeitschr.  f.  pbysiol.  Cbeni.,  Bd.  25. 


SPECIFIC  a  HA  VITY.  409 

may  fall  to  1.002,  while  after  profuse  perspiration  or  after  drinking  very 
little  water  it  may  rise  to  1.0o5-1.040.  In  new-born  infants  the  specific 
gravity  is  low,  1.007-1.005.  The  determination  of  the  specific  gravity  is 
an  important  means  of  learning  the  average  amount  of  solids  eliminated 
from  the  organism  with  the  urine,  and  on  this  account  the  determination 
becomes  of  true  value  only  when  at  the  same  time  the  quantity  of  urine 
voided  in  a  given  time  is  determined.  The  different  portions  of  urine 
voided  in  the  course  of  the  24:  hours  are  collected,  mixed  together,  the  total 
quantity  measured,  and  then  the  specific  gravity  taken. 

The  determination  of  the  specific  gravity  is  most  accurately  obtair-^d  Avith 
the  pyknometer.  For  ordinary  cases  the  specific  gravity  may  be  determined 
with  sufficient  accuracy  by  means  of  areometers.  The  areometers  found  in 
the  trade,  or  nrinometers,  are  graduated  from  1.000  to  1.040;  for  exact 
observations  it  is  better  to  use  two  urinometers,  one  graduated  from  1.000  to 
1.020,  and  the  other  from  1.020  to  1.040. 

To  determine  the  specific  gravity  of  urine,  if  necessary  filter  the  urine, 
or  if  it  contains  a  urate  sediment,  first  dissolve  it  by  gentle  heat,  then  pour 
the  clear  urine  into  a  dry  cylinder,  avoiding  the  formation  of  froth.  Air- 
bubbles  or  froth,  when  present,  must  be  removed  with  a  glass  rod  or  filter- 
paper.  The  cylinder,  whicii  must  be  about  ^  full,  must  be  wide  enough  to 
allow  the  nrinometer  to  swim  freely  in  the  liquid  without  touching  the 
sides.  The  cylinder  and  urinometer  should  both  be  dry  or  previously 
washed  with  the  urine.  On  reading,  the  eye  is  brought  on  a  level  with  the 
lower  meniscus — which  occurs  when  the  surface  of  the  liquid  and  the  lower 
limb  of  the  meniscus  coincide;  the  reading  is  then  made  from  the  point 
where  this  curved  line  cuts  the  scale  of  the  urinometer.  If  the  eye  is  not 
in  the  same  horizontal  plane  with  the  convex  line  of  the  meniscus,  but  is 
too  high  or  too  low,  the  surface  of  the  liquid  assumes  the  shape  of  an 
ellipse,  and  the  reading  in  this  position  is  incorrect.  Before  reading  press 
the  urinometer  gently  down  into  the  liquid  and  then  allow  it  to  rise,  and 
wait  until  it  is  at  rest. 

Each  urinometer  is  graduated  for  a  certain  temperature,  which  is  marked 
on  the  instrument,  or  at  least  on  the  best.  If  the  urine  is  not  at  the  proper 
temperature,  the  following  corrections  must  be  made:  For  every  three 
degrees  above  the  normal  temperature  one  unit  of  the  last  order  is  added  to 
the  reading,  and  for  every  three  degrees  below  the  normal  temperature  one 
unit  (as  above)  is  subtracted  from  the  specific  gravity  observed.  For  exam- 
ple, when  a  urinometer  graduated  for  +  15°  C.  shows  a  specific  gravity  of 
1.017  at  4-  24°  C,  then  the  specific  gravity  at  +  15"  C.  =  1.017  +  0.003 
=  1.020. 

"When  great  exactitude  is  required,  as,  for  instance,  a  determination  to 
the  fourth  decimal  point,  we  make  use  of  a  urinometer  constructed  by 
LoHNSTEix.'  JoLLEsMias  also  devised  a  small  urinometer  for  the  deter- 
mination of  the  specific  gravity  of  small  amounts  of  urine,  20-25  c.c.  The 
specific  gravity  may  also  be  determined  by  the  Westphal  hydrostatic 
balance. 

•  Pfliiger's  Arch.,  Bd.  59,  Chem.  Ceutralbl.,  1895,  Bd.  1,  S.  74,  and  1896,  Bd.  2,  S. 
457. 

'  Wien.  med.  Presse,  1897.  No.  8. 


410  UEINE. 

II.  Organic  Physiological  Constituents  of  the  Urine. 

Urea,  Ur,  which  is  ordinarily  considered  as  carbamid,  CO(]SrH,), ,  may 
be  synthetically  prepared  in  several  different  ways,  namely,  from  carbonyl- 
chloride,  or  carbonic-acid  ethyl-ether  and  ammonia,  COCl,  -j-  SlSTHj  = 
CO(NH,),  +  2HC1,  or  (C,HJ,.0,.CO  +  2NH3  =  2(C,H,.0H)  +  CO,(NH), ; 
by  the  nietameric  decomposition  of  ammonium  cyanate,  CO.N.NH^  = 
CO(iSrHJ„  (WoHLER,  1828);  and  in  many  other  ways.  It  is  also  formed 
by  the  decomposition  or  oxidation  of  certain  bodies  found  in  the  animal 
organism,  such  as  creatin  and  uric  acid. 

Urea  is  found  most  abundant  in  the  urine  of  carnivora  and  man,  but  in 
smaller  quantities  in  that  of  herbivora.  The  quantity  in  human  urine  is 
ordinarily  20-30  p.  m.  It  has  also  been  found  in  small  quantities  in  the 
urine  of  amphibians,  fishes,  and  certain  birds.  Urea  occurs  in  the  perspira- 
tion in  small  quantities,  and  as  traces  in  the  blood  and  in  most  of  the 
animal  fluids.  It  also  occurs  in  rather  large  quantities  in  the  blood,  liver, 
muscle '  and  bile  "  of  sharks.  Urea  is  also  found  in  certain  tissues  and 
organs  of  mammals,  especially  in  the  liver  and  spleen,  although  only  in 
small  aniouuts.  Under  pathological  conditions,  as  in  obstructed  excretion, 
urea  may  appear  to  a  considerable  extent  in  the  animal  fluids  and  tissues. 
Schondoeff'  finds  that  the  quantity  of  urea  in  the  organs  of  a  dog  fed 
witli  meat  is,  with  the  exception  of  the  muscles  (0.884  p.  m.),  the  heart 
f  1.734  p.  m.),  and  the  kidneys  (6.695  p.  m.),  about  the  same  as  the  blood, 
or  an  average  of  1.2  p.  m.  In  human  blood  the  quantity  of  urea  on  a 
mixed  diet  Avas  0.611  p.  m.,  and  about  the  same  quantity  was  found  in 
woman's  milk  and  the  amniotic  fluid. 

The  quantity  of  urea  which  is  voided  in  24  hours  on  a  mixed  diet  is  in 
a  grown  man  about  30  grms.,  in  women  somewhat  less.  While  children 
void  less,  the  excretion  relative  to  their  body-weight  is  greater  than  in 
grown  persons.  The  physiological  significance  of  urea  lies  in  the  fact 
that  this  body  forms  in  man  and  carnivora,  from  a  quantitative  standpoint, 
the  most  important  nitrogenous  final  product  of  the  metabolism  of  proteid 
bodies.  Ou  this  account  the  elimination  of  urea  varies  to  a  great  extent 
with  the  katabolism  of  the  proteid,  and  above  all  with  the  quantity  of 
absorl)a1:)le  proteids  in  the  food  taken.  The  elimination  of  urea  is  greatest 
after  an  exclusive  meat  diet,  and  lowest,  indeed  less  than  during  starvation, 
after  the  consumption  of  non- nitrogenous  bodies,  for  these  diminish  the 
metabolism  of  the  proteids  of  the  body. 

If  the  consumption  of  the  proteids  of  tlie  body  is  increased,  then  the 

'  V.  Scliroder,  Zeilsclir.  f.  pbysiol.  Chem.,  Bd.  14. 
'  Haimnurslen,  ibid..  Bd.  24. 
'PllUger's  Arab.,  Bd.  74. 


UREA.  411 

elimination  of  nitrogen  is  correspondingly  increased.  Tliis  is  found  to  be 
the  case  in  fevers,  cachexia,  diabetes,  after  jjoisoning  witli  arsenic,  antimony, 
phosphorns,  and  other  protoplasm  poisons,  by  a  diminished  supply  of  oxygen 
— as  in  severe  and  continuous  dyspnoea,  poisoning  with  carbon  monoxide, 
hemorrhage,  etc.  In  these  cases  it  used  to  be  considered  that  it  was  due  to 
an  increased  elimination  of  urea,  because  no  exact  difference  was  made 
between  the  quantity  of  urea  and  the  total  quantity  of  nitrogen  in  the 
urine.  Recent  researches  have  conclasively  demonstrated  the  untrust- 
worthiness  of  these  observations.  Since  Pfluger  and  Bohland  have 
shown  that  IQ^  of  the  total  nitrogen  of  the  urine  exists  under  physiological 
conditions  as  other  combinations,  not  urea,  attention  has  been  called  to 
the  relationship  of  the  different  nitrogenous  constituents  of  the  urine  to 
each  other,  and  it  has  been  found,  under  pathological  conditions,  that  this 
relationship  may  vary  very  considerably,  especially  in  regard  to  the  urea. 
We  have  numerous  determinationsby  ditferent  investigators,  such  as  BoH- 
LAND,  E.  ScnuLTZE,  Camerer,  Voges,  Morner  and  S.ioqvist,  Gumlich, 
BoDTKER,'  and  others,  on  the  relationship  of  the  different  nitrogenous 
constituents  to  each  other  in  normal  urine  of  adults.  S.toqvist  has  made 
similar  determinations  on  new-born  babes  from  1-7  days  old.  From  all 
these  analyses  we  obtain  the  following  figures  (A  for  adults  and  B  for  new- 
born babes).     Of  the  total  nitrogen,  we  have: 

A  B 

Urea 84-91^  73-76^: 

Ammonia 2-5  7.8-9.6 

Uricacid 1-3  3.0-8.5 

Remaining  uitrogeneous  substances  (extractives). . . .     7-12  7.3-14.7 

The  different  relationship  between  uric  a<3id,  ammonia,  and  urea  nitrogen 
in  children  and  adults  is  remarkable,  since  the  urine  of  children  is  consider- 
ably richer  in  uric  acid  and  ammonia,  and  considerably  poorer  in  urea,  than 
the  urine  of  adults.  The  absolute  quantity  of  urea  nitrogen  in  adults 
amounts  to  about  10-lG  grms.  per  day.  In  disease  the  proportion  of 
the  nitrogenous  substances  may  be  markedly  changed,  and  a  decrease  in 
the  quantity  of  urea  and  an  increase  in  the  quantity  of  anmionia  have  been 
observed  in  certain  diseases  of  the  liver.  This  will  be  treated  of  in  detail 
in  connection  with  the  formation  of  urea  in  the  liver.  It  is  natural  that 
there  is  a  diminished  formation  of  urea  in  diminished  administration  of 
proteids  or  diminished  katabolism  of  jiroteids.     In  diseases  of  the  kidneys 

'  Pfluger  and  Bobland,  Pfliiger's  Arch..  Bdd.  38  and  43  ;  Bohland,  ibid.,  Bd.  43; 
Schultze,  ibid..  Bd.  45;  Camerer,  Zeilsclir.  f.  Biologie,  Bdd.  24.  27,  and  28;  Voges, 
Ueber  die  Miscbung  der  stickstoCfbultigeu  Bestandtbeile  ini  Ilarn,  etc.  (Inaug.-Diss., 
Berlin,  1892)  cited  from  Maly's  Jahresber.,  Bd.  22;  K.  Morner  and  Sj5qvist,  Siiand. 
Arcb.  f.  Physiol.,  Bd.  2.  See  also  Sj5qvist.  Nord.  med.  Arkiv.,  1892,  No.  36,  and  1894, 
No.  10;  Gumlich,  Zeitschr.  f.  pbysiol.  Cbem.,  Bd.  17;  Bcidtker,  see  Maly's  Jahresber., 
Bd.  26. 


412  URINE. 

whicli  disturb  or  destroy  the  integrity  of  the  epithelium  of  the  tortuonff 
urinary  passages  the  elimination  of  urea  is  considerably  diminished. 

Formation  of  Urea  in  the  Organism.  The  experiments  to  produce  urea 
directly  from  proteids  by  oxidation  have  not  led  to  any  positive  results. 
Among  the  basic  bodies  occurring  in  the  hydrolytic  cleavage  products  of 
proteids  we  find  lysatin  and  arginin,  which  are  also  formed  in  tryptic  diges- 
tion, and  these  bodies  yield  urea  by  the  action  of  alkalies  (Chapter  II).  It 
is  therefore  possible  to  prepare  urea  by  the  hydrolytic  cleavage  of  proteids, 
with  these  bodies  as  intermediate  products,  and  according  to  Drechsel. 
about  10^  of  the  urea  may  be  accounted  for  in  this  way.  A  part  of  the 
urea  may  be  produced  by  the  action  of  alkalies  on  creatin  or  creatinin. 

The  amido-acids  are  also  considered  as  mother-substances  of  urea.  By 
the  researches  of  Schultzei^  and  N"encki  and  Salkowski  with  leucin  and 
glycocoll  and  those  of  v.  Knieriem  with  asparagin,  it  has  been  shown  that 
the  amido-acids  are  in  part  converted  into  urea  in  the  animal  organism. 
Recent  investigations  by  Salaskin  with  the  three  amido-acids,  glycocoll, 
leucin,  and  aspartic  acid,  have  unmistakably  shown  that  the  living  dog- 
liver,  supplied  with  arterial  blood,  has  the  property  of  transforming  the  above 
amido-acids  into  urea  or  a  closely  allied  substance.  The  researches  of 
LoEWi/with  the  "urea-forming"  enzyme  of  the  liver,  discovered  by 
RiCHTET,  and  glycocoll  or  leucin,  as  also  the  researches  of  Ascoli,'  have 
led  to  similar  results.  Nothing  can  be  stated  in  regard  to  the  extent  of 
formation  of  amido-acids  in  the  physiological  destruction  of  proteids  in  the 
animal  body,  with  the  exception  of  those  formed  in  the  intestinal  digestion. 
The  possibility  of  such  a  formation  of  urea  is  beyond  dispute. 

Nothing  positive  can  be  said  in  regard  to  the  manner  in  which  the 
formation  of  urea  originates;  but  it  is  admitted  that  it  is  partly  an  ammonia 
formation  and  partly  the  formation  of  carbamic  acid. 

The  possibility  of  a  formation  of  urea  from  ammonia  has  been  jjositively 
shown.  Thus  the  researches  of  v.  Knieriem,  Salkowski,  Feder, 
I.  MuNK,  CoRANDA,  ScHMiEDEBERG  and  Fr.  Walter,  and  Haller- 
WORDEX,^  on  the  behavior  of  ammonium  salts  in  the  animal  body  and  the 
elimination  of  the  ammonia  under  various  conditions,  have  shown  that  not 
'-nly  ammonium  carbonate,  but  also  such  ammonium  salts  which  are  burnt 
into  carbonate  in  the  organism  are  transformed  iuto  urea  by  carnivora  as 
well   as  herbivora.     v.   Schroeder,^  by  irrigating  the  living  dog's  liver 

'  Schiillzen  and  Neucki,  Zeitscbr.  f.  Biologie,  Bd.  8;  -v.  Kuieiiem,  ibid.,  Bd.  10; 
Salkowski,  Zeilschr.  f.  ])hysiol.  Cliem.,  Bd.  4;  Salaskin,  ibid.,  Bd.  25;  Loewi,  ibid., 
Bd.  25  ;  Richtet,  Compt.  rend.,  Tome  118,  and  Compt.  rend.  soc.  bio].,  Tome  49  :  Ascoli, 
Pfluger'8  Arcli.,  Bd.  72. 

■^  V.  Knieriem,  Zeitscbr.  f.  Biologie,  Bd.  10;  Feder,  ibid.,  Bd.  13;  Salko^vski,  Zeit- 
scbr. f.  Biologie,  Bd.  1  ;  Munk,  ibid.,  Bd.  2;  Corandn,  Arch.  f.  e.xp.  Patb.  u.  Pbarm., 
Bd.  12;  Scbriiiedeberg  and  Walter,  ihid.,  Bd.  7;  Ilallerwordeu,  ibid.,  Bd.  10. 

*  Arc)),  f.  exi).  Patb.  ii.  Pbarm.,  Bd.  15.  See  also  Salomon,  Virchow's  Arch.,  Bd.  97. 


FORMATION  OF   UREA.  41  Ij 

with  blood  treated  with  ammonium  carbonate  or  ammonium  formate,  lias 
shown  that  the  formation  of  urea  takes  place,  at  least  in  part,  in  this  organ. 
Nencki,  Pawlow  and  Zaleski  '  have  found  that  in  dogs  the  quantity  of 
ammonia  in  the  blood  from  the  portal  vein  is  a])Out  3.5  times  greater  than 
from  the  hepatic  vein,  and  they  claim  that  the  liver  retains  in  great  i)art 
the  ammonia  supplied.  The  formation  of  urea  from  ammonia  in  the  liver 
is  a  positively  proved  fact,  and  the  urea  formation  from  ammoniam  carbonate 
is  to  be  considered  as  a  synthesis  with  the  elimination  of  water. 

We  have  also  important  observations  which  give  support  to  the  views  of 
ScnuLTZEX  and  Nencki,'  namely,  that  the  amido-acids  are  transformed 
into  nrea  with  carbamic  acid  as  an  intermediate  step.  Dkecusel  has 
shown  that  the  amido-acids  yield  carbamic  acids  by  oxidation  in  alkaline 
fluid  outside  of  the  organism,  and  he  obtained  urea  from  ammonium  car- 
bamate by  passing  an  alternate  electric  current  through  its  solution,  namely, 
by  alternate  oxidation  and  redaction.  Drechsel  has  also  been  able  to 
detect  small  quantities  of  carbamates  in  blood,  and  later  in  conjunction  with 
Abel  he  detected  carbamic  acid  in  alkaline  horse's  urine.  Drechsel 
therefore  accepts  the  formation  of  nrea  from  ammonium  carbamate,  and 
according  to  him  the  alternating  oxidation  and  reduction  take  place  in  the 
following  way: 

H.N.O.CO.XH,  -f  0   =  H,X.O.CO.NII,  +  H,0 
and 

H,N.O.CO.NH,  +  H,  =  H,N.CO.NH,  -f  H,0. 

Urea 

Abel  and  Muirhead  '  have  later  observed  an  abundant  elimination  of 
carbamic  acid  in  human  and  dog's  urine  after  the  administration  of  large 
quantities  of  milk  of  lime,  and  the  probability  of  the  regular  appearance  of 
this  acid  in  normal  acid  human  and  dog's  urine  has  been  demonstrated  by 
M.  Nencki  and  Hahn.*  These  last-mentioned  investigators  have  also 
given  very  important  supjiort  to  the  theory  of  the  formation  of  urea  from 
ammoninm  carbamate  by  observations  on  dogs  with  Eck's  fistula.  In  this 
case  the  portal  vein  is  directly  connected  with  the  inferior  vena  cava,  and  a 
communication  is  thus  established  so  that  the  blood  of  the  portal  vein  flows 
directly  into  the  vena  cava,  without  passing  through  the  liver.  Xencki 
and  Hahn  observed  violent  symptoms  of  poisoning  in  dogs  operated  upon 

'  Arch,  des  sciences  biol.  de  St.  Petersbourg,  Tome  4. 

«  Zeitschr.  f.  Biologic,  Bd.  8. 

3  Drechsel,  Ber.  d.  siichs.  Gesellsch.  d.  Wisseiiscli.,  1875.  See  also  Jouru.  f.  prakt. 
Chem.  (N.  F.),  Bdd.  12,  16,  and  22  ;  Abel,  Du  Bois-Rcymond's  Arch.,  1891 ;  Abel  and 
Muirhead,  Arch.  f.  exp.  Path.  u.  Phami.,  Bd.  31. 

*  Hahn,  Masscn,  Nencki  et  Pawlow,  La  fistule  d'Eck  de  la  veine  cave  inferieur  et  de 
la  veine  porte'  etc.     Arch,  des  sciences  biol.  de  St.  Petersbourg,  Tome  1,  No.  4,  1892. 


414  URINE. 

by  Pawlow  and  Massex,  and  these  symptoms  "were  quite  identical  with 
those  obtained  on  introducing  carbamate  into  the  blood.  These  symptoms 
also  appear  after  the  introduction  of  carbamate  into  the  stomach,  while  the 
introduction  of  carbamate  into  the  stomach  of  a  normal  dog  had  no  action. 
As  these  observers  also  found  that  the  urine  of  the  dog  on  which  the  opera- 
tion was  made  was  richer  in  carbamate  than  that  of  the  normal  dog,  they 
conclude  that  the  symptoms  were  due  to  the  non-transformation  of  the 
ammonium  carbamate  into  urea  in  the  liver,  and  they  consider  the  am- 
monium carbamate  as  the  substance  from  which  the  urea  is  derived  in  the 
liver  of  mammals. 

The  view  as  to  the  formation  of  urea  from  ammonium  carbamate  does 
not  contradict  the  above  statement  as  to  the  transformation  of  carbonates 
into  urea,  since  we  can  imagine  that  the  carbonate  is  first  converted  into 
carbamate  with  the  expulsion  of  a  molecule  of  water,  and  that  this  then  is 
transformed  into  urea  with  the  expulsion  of  a  second  molecule  of  water. 

F.  HoFMEiSTER '  has  found  in  the  oxidation  of  different  members  of 
the  fatty  series,  as  well  as  in  amido-acids  and  proteids,  that  urea  was  formed 
in  the  presence  of  ammonia,  and  he  therefore  suggests  the  possibility  that 
urea  may  be  formed  by  an  oxidation-synthesis.  According  to  him,  in  the 
oxidation  of  nitrogenous  substances  a  radical  CONH^ ,  containing  the 
amido-group,  unites  at  the  moment  of  formation  with  the  radical  NH^ 
remaining  on  the  oxidation  of  ammonia,  forming  urea. 

Besides  the  above-mentioned  theories  as  to  the  formation  of  nrea,  we 
have  others  which  will  not  be  given,  because  the  only  theory  which  has  thus, 
far  been  positively  demonstrated  is  the  formation  of  urea  from  ammonium 
compounds  and  amido-acids  in  the  liver. 

The  liver  is  the  only  organ  in  which,  up  to  the  present  time,  a  formation 
of  urea  has  been  directly  detected ;  ^  and  the  question  arises,  what  importance 
has  this  urea  formation  taking  place  in  the  liver  ?  Is  the  urea  wholly 
or  chiefly  formed  in  the  liver  ? 

If  the  liver  is  the  only  organ  forming  urea  it  is  to  be  expected,  on  the 
extirpation  or  atrophy  of  that  organ,  that  a  reduced  or,  in  short  experiments, 
at  least  a  strongly  diminished  elimination  of  urea  occurs.  As  at  least  a  part 
of  the  urea  is  formed  in  the  liver  from  ammonium  compounds,  a  simul- 
taneous increase  in  the  elimination  of  ammonia  is  to  be  expected. 

The  extirpation  and  atrophy  experiments  on  animals  made  by  different 
methods  by  Nencki  and  Haiix,  Slosse,  Lieblein,  Nencki  and  Pawlow  ' 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  37. 

'  In  regard  to  the  investi,!,'ation8  of  Prevost  aud  Dumas,  Meissner,  Voit,  Grebant, 
Gscheidlen  and  Salkowski,  aud  others,  on  the  role  of  the  kidneys  in  the  formation  of 
urea,  see  v.  Schroeder,  Arch.  f.  exp.  Path.  \\.  Pharm.,  Bdd.  15  and  19,  and  Voit,  Zeit- 
schr.  f.  Biologic,  Bd.  4. 

*  Nencki  and  Halin,  1.  c. ;  Slo.sse,  Du  Boi.s-Ileymond's  Arch.,  1890;  Lieblein,  Arch. 
f.  exp.  Path.  n.  Pliarm.,  Bd.  33  ;  Nencki  and  Pawlow,  Arch,  des  scienc.  de  St.  Peters- 
bourg,  Tome  5.     See  also  v.  Meister,  Maly's  Jahresber. ,  Bd.  25. 


PROPRRIIES  AND   RK ACTIONS  OF   UREA.  41 5 

have  shown  that  a  rather  marked  increase  of  ammonia  and  a  diminislied 
elimination  of  urea  take  place  after  the  operation,  but  also  tliat  there  are 
cases  in  which,  irrespective  of  the  pronounced  atrophy,  an  abundant  forma- 
tion of  nrea  occurs,  and  no  appreciable  if  any  change  in  the  proportion 
of  ammonia  to  the  total  nitrogen  and  urea  is  observed.  After  extirpation 
of  the  organs  of  the  posterior  part  of  the  body,  especially  the  liver  and 
kidneys,  from  the  circulation  Kaufmanx  '  also  found  an  important  increase 
in  the  urea  of  the  blood,  and  these  different  observations  show  that  the  liver 
is  not  the  only  organ,  in  the  various  animals  experimented  upon,  in  which 
nrea  is  formed. 

The  observations  made  by  numerous  investigators '  on  human  beings 
with  cirrhosis  of  the  liver,  acute  yellow  atrophy,  and  phosphorus  poisoning 
have  led  to  the  same  result.  TVe  learn  from  these  investigations  that  in 
certain  cases  the  proportion  of  the  nitrogenous  substances  may  be  so  changed 
that  urea  is  only  50-GO^^  of  the  total  nitrogen,  while  in  other  cases,  on  the 
contrary,  even  in  very  extensive  atrophy  of  the  liver-cells,  the  formation  of 
urea  is  not  diminished,  neither  is  the  proportion  between  the  total  nitrogen, 
urea,  and  ammonia  essentially  changed.  Even  in  the  cases  in  which  the 
formation  of  urea  was  relatively  diminished  and  the  elimination  of  ammonia 
considerably  increased  we  must  not  without  further  investigation  assume  a 
reduced  ability  of  the  organism  to  produce  urea.  An  increased  elimination 
of  ammonia  may,  as  shown  by  Munzer  in  the  case  of  acute  phosphorus 
poisoning,  be  dependent  upon  the  formation  of  abnormally  large  quantities 
of  acids,  caused  by  abnormal  metabolism,  and  these  acids  require  a  greater 
quantity  of  ammonia  for  their  neutralization  according  to  the  law  of  the 
elimination  of  ammonia,  which  will  be  given  later. 

For  the  present  we  are  not  justified  in  the  statement  that  the  liver  is 
the  only  organ  in  which  urea  is  formed,  and  continued  investigation  only 
can  yield  further  information  as  to  the  extent  and  importance  of  the  forma- 
tion of  urea  from  ammonia  compounds  in  the  liver. 

P^'operties  and  lieadions  of  Urea.  Urea  crystallizes  in  needles  or  in 
long,  colorless,  four-sided,  often  hollow,  anhydrous  rhombic  prisms.  It  has 
a  neutral  reaction  and  produces  a  cooling  sensation  on  the  tongne  like  salt- 
petre. It  melts  at  130-132°  C,  but  already  decomposes  at  about  100°  C. 
At  ordinary  temperatures  it  dissolves  in  equal  weight  of  water  and  in  five 
parts  alcohol;  it  requires  one  part  boiling  alcohol  for  solution;  it  is  insoluble 

'  Compt.  rend.  Soc.  biol..  Tome  46,  and  Arch,  de  Physiol.  (5),  Tome  6. 

»  See  Ilalleiworden,  Arch.  f.  exp.  Piith.  ii.  Pliarm.,  Bd.  12  ;  Weiiitraiid,  ibid.,  Bd. 
31;  Miinz-cr  and  Winteiberg,  ibid.,  Bd.  33;  Stadelmaiiii,  Deutsch.  Arch.  f.  klin.  Med., 
Bd.  33  ;  Fawitzki,  ibid.,  Bd.  4.") ;  Aliinzer,  ibid.,  Bd.  52  ;  Fninkel,  Berlin,  klin.  Wocheu- 
schr.,  1878  ;  Richter,  ibid.,  1896  ,  Morncrand  Sjoqvist,  Skand.  Arch.  f.  Physiol.,  Bd.  2, 
and  Sjoqvist,  Nord.  Med.  Arkiv.,  1892  ;  Gumlich.  Zeitschr.  f.  physiol.  Chcm.,  Bd.  17  ; 
v.  Noordcn,  Lehrb.  d.  Palhol.  des  Stoffwechsels,  S.  287. 


416  URINE. 

iu  alcohol-free  ether,  and  also  in  chloroform.  If  urea  in  substance  is  heated 
in  a  test-tube,  it  melts,  deconij^oses,  gives  off  ammonia,  and  leaves  finally  a 
non- transparent  "white  residue  which,  among  other  substances,  contains 
also  cyanuric  acid  and  hiiiret,  which  dissolves  in  water,  giving  a  beautiful 
reddish-violet  liquid  with  copper  sulphate  and  alkali  {biuret  reaction).  On 
heating  with  baryta-water  or  caustic  alkali,  also  in  the  so-called  alkaline 
fermentation  of  urine  caused  by  micro-organisms,  urea  splits  into  carbon 
dioxide  and  ammonia  with  the  addition  of  water.  The  same  decomposition 
products  are  produced  when  urea  is  heated  with  concentrated  sulphuric 
acid.  An  alkaline  solution  of  sodium  hypobromite  decomposes  urea  into 
nitrogen,  carbon  dioxide,  and  water  according  to  the  equation 

CON^H,  +  SNaOBr  =  3KaBr  +  CO,  +  2H,0  +  N,. 

With  a  concentrated  solution  of  f nrfurol  and  hydrochloric  acid  urea  in 
substance  gives  a  coloration  passing  from  yellow,  green,  blue,  to  violet,  and 
then  beautiful  parple-violet  after  a  few  minutes  (Schiff's  reaction). 
According  to  Huppert  '  the  test  is  best  performed  by  taking  2  c.c.  of  a 
concentrated  fnrfurol  solution,  4-0  drops  concentrated  hydrochloric  acid, 
and  adding  to  this  mixture,  which  must  not  be  red,  a  small  crystal  of  urea. 
A  deep  violet  coloration  appears  in  a  few  minutes. 

Urea  forms  crystalline  combinations  with  many  acids.  Among  these 
tlie  one  with  nitric  acid  and  the  one  with  oxalic  acid  are  the  most  important. 

Urea  Nitrate,  C0(XHJj.HN03.  On  crystallizing  quickly  this  com- 
bination forms  thin  rliombic  or  six-sided  overlapping  tiles,  colorless  plates, 
whose  point  has  an  angle  of  83°.  When  crystallizing  slowly,  larger  and 
uiiicker  rhombic  jjiHars  or  jilates  are  obtained.  This  combination  is  rather 
easily  soluble  in  pure  water,  but  is  considerably  less  soluble  in  water  con- 
taining nitric  acid;  it  may  be  obtained  by  treating  a  concentrated  solution 
of  urea  with  an  excess  of  strong  nitric  acid  free  from  nitrous  acid.  On 
heating  this  combination  it  volatilizes  without  leaving  a  residue. 

This  compound  may  be  emploj^ed  with  advantage  in  detecting  small  amounts  of 
urea.  A  drop  of  tlie  C(nicentraled  solution  is  placed  on  a  microscope- slide  and  the 
cover-glass  placed  upon  it;  a  drop  of  nitric  acid  is  then  placed  on  the  side  of  the  cover- 
glass  and  allowed  to  flow  under.  The  formation  of  crystals  begins  wliere  the  solution 
and  the  nitric  acid  meet.  AlkMli  nitrates  may  crystallize  very  similarly  to  urea  nitrate 
when  they  are  contaminated  with  other  l)odies;  therefore,  in  testing  for  urea,  the  crys- 
tals must  be  identified  as  urea  nitrate  by  heating  and  by  other  means. 

Urea  Oxalate,  2.C0(NII,)^.II,C,0^.  This  compound  is  more  spar- 
ingly soluble  in  water  than  the  nitric-acid  compound.  It  is  obtained  in 
rhombic  or  six-sided  prisms  or  plates  on  adding  a  saturated  oxalic-acid 
golution  to  a  concentrated  solution  of  urea. 

Urea  also  forms  combinations  with  mercuric  nitrate  in  variable  propor- 

'  Huppert-Neubauer,  Analyse  des  Ilarues,  10.  Aufl.,  S.  296. 


ESTIMATION  OF  UREA.  417 

tions.     If   a   very   faintly   acid   mercuric-nitrate    solntion   is   added    to   a 

two-per-ceut  solntion  of  urea   and   the   mixture   carefully   neutralized,   a 

combination  is  obtained  of  a  constant  composition  which  contains  for  every 

10  parts  of  urea  72  parts  mercuric  oxide.     This  compound  serves  as  the 

basis  of  Liebig's  titration  method.     Urea  combines  also  with  salts,  forming 

mostly  crystulTizable  combinations,  as,  for  instance,  with  sodium  chloride, 

with  the  chlorides  of  the  heavy  metals,  etc.     An  alkaline  but  not  a  neutr^^l 

solution  of  urea  is  precipitated  with  mercuric  chloride. 

If  urea  is  dissolved  in  dilute  hydrocbloric  acid  and  then  an  excess  of  formaldehyde 
added,  a  thick,  white,  /jranular  i)recipitate  is  obtained  which  is  difficultly  soluble  and 
whose  couiposilion  is  somewhat  disputed.'  With  phenyl-hydraziu,  urea  in  strong  acetic 
acid  gives  a  colorless  crystulline  combination  of  phenyl-semicarbazid,  CdlsNII.NH. 
CONHa, which  is  soluble  with  ditliculty  in  cold  water,  and  melts  at  172"  C.  (.JAFFfi"). 

The  method  of  preparing  urea  from  urine  is  chiefly  as  follows:  Concen- 
trate the  urine,  which  has  been  faintly  acidified  with  sulphuric  acid,  at  a 
low  temperature,  add  an  excess  of  nitric  acid,  at  the  same  time  keeping  the 
mixture  cool,  press  the  precipitate  well,  decompose  it  in  water  with  freshly 
precipitated  barium  carbonate,  dry  on  the  water-bath,  extract  the  residue 
with  strong  alcohol,  decolorize  when  necessary  with  animal  charcoal,  and 
filter  while  warm.  The  urea  which  crystallizes  on  cooling  is  jKirified  by 
recrystallization  from  warm  alcohol.  A  further  quantity  of  urea  may  be 
obtained  from  the  mother-liquor  by  concentration.  The  urea  is  purified 
from  contaminating  mineral  bodies  by  redissolving  in  alcohol-ether.  If  it 
is  only  necessary  to  detect  the  presence  of  urea  in  urine,  it  is  sufficient  to 
concentrate  a  little  of  the  urine  on  a  watch-glass  and,  after  cooling,  treat 
with  an  excess  of  nitric  acid.     In  this  way  we  obtain  crystals  of  urea  nitrate. 

Quantitative  Estimation  of  the  Total  Nitrogen  and  Urea  in  Urine. 
Among  the  various  methods  proposed  for  the  estimation  of  the  total  nitro- 
gen, that  suggested  by  Kjeldaiil  is  to  be  recommended.  But  as  Lieuig's 
method  for  the  estimation  of  urea  is  really  a  method  for  determining  the 
total  nitrogen,  and  as  the  physician  has  not  always  at  hand  the  apparatus 
and  utensils  necessary  for  a  Kjeldaul  determination,  he  often  makes  use 
of  this  method;  hence  it  will  be  given  in  detail. 

K.ieldahl's  method  consists  in  transforming  all  the  nitrogen  of  the 
organic  substances  into  ammonia  by  heating  with  a  sufliciently  concentrated 
sulphuric  acid.  The  ammonia  is  distilled  off  after  supersaturating  with 
alkali,  and  the  ammonia  collected  in  standard  sulphuric  acid.  The  follow- 
ing reagents  are  necessary. 

1.  Sulphuric  Acid.  Either  a  mixture  of  equal  volnmes  pure  concen- 
trated and  fuming  sulphuric  acid  or  else  a  solution  of  200  grms.  phosphoric 
anhydride  in  1  litre  pure  concentrated  sulphuric  acid.  2.  Caustic  soda  free 
from  nitrates,  ;>0— iO'e  solution.  The  quantity  of  this  caustic-soda  solution 
necessary  to  neutralize  10  c.c.  of  the  acid  mixture  must  be  determined. 
3.  ^Metallic  mcrcuri/  or  pure  yellow  mercuric  oxide.  (The  addition  of  this 
facilitates  the  destruction  of  the  organic  substances.)     4.  A  jwtassiuin-sul- 

'  See  Tollens  and  his  pupils,  Ber.  d.  deulsch.  chem.  Gcsellsch.,  Bd.  29,  S.  2751  ; 
Ooldschmidt.  ibid.,  Bd.  29,  and  Chem.  Centralbl.,  1897,  Bd.  1,  S.  33;  Thorns,  Utid.,  Bd. 
2,  S.  144  and  737. 

•Zeitschr.  f.  physiol.  Chem.,  Bd.  22. 


418  URINE. 

pMde  solution  of  4^,  whose  object  is  to  decompose  any  mercuric  amicf 
combination  which  might  not  evolve  its  ammonia  completely  on  distillation 
with  caustic  soda.     5.  \  normal  siilphnric  acid  and  \  normal  caustic  potash. 

In  performing  the  determination  5  c.c.  of  the  carefully  measured  filtered 
urine  is  placed  in  a  long-necked  Kjeluahl  flask,  a  drop  of  mercury  or 
about  0.3  grm.  mercuric  oxide  added,  and  then  treated  with  10-15  c.c.  of 
the  strong  sulphuric  acid.  The  contents  are  heated  very  carefully,  placing 
the  flask  at  an  angle,  until  it  just  begins  to  boil  gently,  and  continue  this 
for  about  half  an  hour  or  until  the  mixture  is  colorless.  On  cooling  the 
contents  are  transferred  to  a  voluminous  distilling  flask,  carefully  washing 
the  Kjeldahl  flask  with  water,  and  tlie  greater  part  of  the  acid  is  neutralized 
by  caustic  soda.  A  few  zinc  shavings  are  added  to  prevent  too  raj)id 
ebullition  on  distillation,  and  then  an  excess  of  caustic-soda  solution,  which 
has  previously  been  treated  with  30-40  c.c.  of  the  potassium-sulphide  solu- 
tion. The  flask  is  quickly  connected  with  the  condenser  tube  and  all  the 
ammonia  distilled  off.  In  order  to  prevent  loss  of  ammonia  it  is  best  to 
lower  the  end  of  the  exit- tube  below  the  surface  of  the  acid,  and  the- 
regurgitation  of  the  acid  is  prevented  by  having  a  bulb  blown  on  the  exit- 
tube.  JSTot  less  than  25-30  c.c.  of  the  standard  acid  is  used  for  every 
5  c.c.  of  urine,  and  on  completion  of  the  distillation  the  acid  is  retitrated 
with  \  normal  caustic  soda,  using  rosolic  acid,  tincture  of  cochineal,  or 
lacmoid  as  indicator.  Each  cubic  centimetre  of  the  acid  corresponds  to 
2.8  milligrammes  nitrogen.  As  a  control  and  in  order  to  see  the  purity  of 
the  reagents,  or  to  eliminate  any  error  caused  by  an  accidental  quantity  of 
ammonia  in  the  air,  we  always  make  a  blind  experiment  with  the  reagents. 

Liebig's  method  is  based  upon  the  fact  that  a  dilute  solution  of  mer- 
curic nitrate  under  proper  conditions  precipitates  all  the  urea,  forming  a 
compound  of  constant  comjoosition.  As  indicator,  a  soda  solution  or  a  thin 
paste  of  sodium  bicarbonate  is  used.  An  excess  of  mercuric  nitrate  produces 
herewith  a  yellow  or  yellowish-brown  combination,  while  the  combination 
of  urea  and  mercury  is  white.  Pfluger'  has  given  full  particulars  of  this 
method;  therefore  we  will  describe  Pfluger's  modification  of  Liebig's 
method. 

As  phosphoric  acid  is  also  precipitated  by  the  mercuric-nitrate  solution, 
this  must  be  removed  from  the  urine  by  the  addition  of  a  baryta  solution 
before  titration.  Pfluger  also  suggested  that  the  acidity  produced  by  the 
mercury  solution  be  neutralized  during  titration  by  the  addition  of  a  soda 
solution.     The  liquids  Jiecessary  for  the  titration  are  the  following: 

1.  Mercuric  Nitrate  Solution.  This  solution  is  calculated  for  a  2^  urea 
Bolution,  and  20  c.c.  of  the  first  should  correspond  to  10  c.c.  of  the  latter. 
Each  c.c.  of  the  mercury  solution  corresponds  to  0.01  gi'm.  urea.  As  a 
small  excess  of  IlgO  is  necessary  in  the  urine  to  make  the  final  reaction 
(with  alkali  carbonate  or  bicarbonate)  appear,  each  c.c.  of  the  mercury 
solution  must  contain  0.0772  instead  of  0.0720  grm.  HgO.  The  mercury 
solution  contains  therefore  77.2  grms.  HgO  in  one  litre. 

The  solution  may  ha  prepared  from  pure  mercury  or  mercuric  oxide  l)y  dissolvinsj; 
in  nitric  acid.  The  solution,  freed  as  completely  as  possible  from  an  excess  of  acid,  is 
diluted  by  the  careful  addition  of  water,  stirring  meanwhile,  until  it  has  a  specific 
gravity  of  1.10,  or  a  little  higher,  at  +  20°  C.     The  solution  is  standardized  with  a  2% 

'  Pfluger,  and  Pfluger  and  Bohland,  in  Pflliger's  Arch.,  Bdd.  21,  36,  37,  and  40. 


LJEBIG'S  METHOD.— ESTIMATION  OF  UREA.  419 

solution  of  pure  uvea  which  has  beon  dried  over  sulpliuric  acid,  and  tlio  operation  con- 
(lucttHl  as  will  bo  (iescribcd  later.  If  the  solution  is  Un>  ccnieentraled,  ii  is  corrected  by 
tlie  carclul  addition  of  the  necessary  amount  of  water,  avoiding  precipitatiiMi  of  basic 
salt,  and  titrating  again.  The  solution  is  correct  if  19.8  c.  c.  of  it,  added  at  once  to 
10  c.  c.  of  the  urea  solution  and  the  necessar}-  quaniiy  of  normal  s(jda  solution  (11-12 
c.  c.  or  more)  to  nearly  completely  neutralize  the  liquid,  gives  the  final  reaction  when 
exactly  20  c.  c.  of  the  mercury  solution  has  been  employed. 

2.  Baryta  Solution.  This  consists  of  1  vol.  barium-nitrate  and  2  vols, 
barinm-liydrate  solution,  both  saturated  at  the  ordinary  temperature. 

3.  KoriiHtl  Soda  Sohition.  This  solution  contains  53  grnis.  pure  anhy- 
drous sodium  carl)oiiate  in  1  litre  of  water.  According  to  Pfluger  a 
solution  having  a  specific  gravity  of  1.053  is  sufficient.  The  amount  of  this 
Boda  solution  necessary  to  completely  neutralize  the  acid  set  free  during  the 
titration  is  determined  by  titrating  with  a  pure  2^c  urea  solution.  To 
facilitate  operations  a  table  can  be  made  showing  the  quantity  of  soda  solu- 
tion necessary  when  from  10  to  35  c.c.  of  the  mercury  solution  is  used. 

Before  the  titration  the  following  must  be  considered.  Tiie  chlorides  of 
the  urine  interfere  with  the  titration  in  that  a  part  of  the  mercuric  nitrate 
is  transformed  into  mercuric  chloride,  which  does  not  precipitate  the  urea. 
Tlie  chlorides  of  the  urine  are  therefore  removed  by  a  silver-nitrate  solution, 
which  also  removes  any  bromine  or  iodine  combinations  which  may  exist  in 
tlie  urine.  If  the  urine  contains  proteid  in  noticeable  amounts,  it  must  be 
removed  by  coagulation  and  the  addition  of  acetic  acid,  but  care  must  be 
taken  that  the  concentration  and  the  volume  of  the  urine  are  not  changed 
during  these  operations.  If  the  urine  contains  ammonium  carbonate  in 
notable  quatitities,  caused  by  alkaline  fermentation,  this  titration  method 
cannot  be  applied.  The  same  is  true  of  urine  containing  leucin,  tyrosin,  or 
medicinal  preparations  jirecipitated  by  mercuric  nitrate. 

In  cases  where  the  urine  is  free  from  proteid  or  sugar  and  not  specially 
poor  in  chlorides,  the  quantity  of  urea,  and  also  the  approximate  quantity 
of  mercuric  nitrate  necessary  for  the  titration,  may  be  learned  from  the 
specific  gravity.  A  specific  gravity  of  1.010  corresponds  to  about  10  p.  m., 
a  specific  gravity  of  1.015  generally  somewhat  less  than  15  p.  m.,  and  a 
specific  gravity  of  1.015-1.020  about  15-20  p.  m.  urea.  "With  a  specific 
gravity  higher  than  1.020  the  urine  generally  contains  more  than  20  p.  m. 
of  urea,  and  above  this  point  the  amount  of  urea  increases  much  more 
rapidly  than  the  specific  gravity,  so  that  with  a  specific  gravity  of  1.030  it 
contains  over  40  p.  m.  urea.  Fever-urines  with  a  specific  gravity  above 
1.020  sometimes  contain  30-40  p.  m.  urea,  or  even  more. 

Preparation^  for  the  Titratiox.  If  a  large  amount  of  urea  is  sus- 
pected from  a  high  specific  gravity,  the  urine  must  first  be  diluted  with  a 
carefully  measured  quantity  of  water,  so  that  the  amount  of  urea  is  reduced 
below  30  p.  m.  In  a  special  portion  of  the  same  urine  the  amount  of 
chlorides  is  determined  by  one  of  the  methods  which  will  be  given  later,  and 
the  number  of  c.c.  of  silver-nitrate  solution  necessary  is  noted.  Then  a 
larger  quantity  of  urine,  say  100  c.c,  is  mixed  with  one  half  or,  if  this  is 
not  Buflicient  to  precipitate  all  the  sulphuric  and  iihosphoric  acids,  with  an 
equal  volume  of  the  baryta  solution;  it  is  tlien  allowed  to  stand  a  little 
while,  and  the  precipitate  is  filtered  through  a  dried  filter.  From  the 
filtrate  containing  the  urine  diluted  with  water  a  proper  quantity,  corre- 
sponding to  about  60  c.c.  of  tlie  original  urine,  is  measured,  and  exactly- 
neutralized  with  nitric  acid  added  from  a  burette,  so  that  the  exact  quantitj- 


420  URINE. 

employed  is  known.  The  nentralized  mixture  of  urine  and  baryta  is  treated 
with  tlie  proper  quantity  of  silver-nitrate  solution  necessary  to  completely 
precipitate  the  chlorides,  which  was  ascertained  by  a  previous  determina- 
tion. The  mixture,  containing  a  known  volume  of  urine,  is  now  filtered 
through  a  dried  filter  into  a  flask,  and  from  the  filtrate  an  amount  is  meas- 
ured corresponding  to  10  c.c.  of  the  original  urine. 

ExECL'Tiois'  OF  THE  TiTRATioi^.  Nearly  the  whole  quantity  of  mercuric- 
nitrate  solution  to  be  used,  and  which  is  known  from  the  specific  gravity  of 
the  urine,  is  added  at  once,  and  immediately  afterwards  the  quantity  of 
soda  solution  necessary,  as  indicated  by  the  table.  If  the  mixture  becomes 
yellowish  in  color,  then  too  much  mercury  solution  has  been  added  and 
another  determination  must  be  made.  If  the  test  remains  white,  and  if  a 
droj)  taken  out  and  placed  on  a  glass  plate  with  a  dark  background  and 
stirred  with  a  drop  of  a  thin  paste  of  sodium  bicarbonate  does  not  give  a 
yellow  color,  the  addition  of  mercury  solution  is  continued  by  adding  ^  and 
then  y'o  c.c,  and  testing  after  each  addition  in  the  following  way:  A  drop 
of  the  mixture  is  placed  on  a  glass  plate  with  a  dark  background  beside  a 
small  drop  of  the  bicarbonate  jiaste.  If  the  color  after  stirring  the  two 
droits  together  is  still  white  after  a  few  seconds,  then  more  mercury  solution 
must  be  added;  if,  on  the  contrary,  it  is  yellowish,  then — if  not  too  much 
mercury  solution  has  been  added  by  inattention — the  result  to  y-^  c.c.  has 
been  found.  By  this  approximate  determination,  which  is  sufficient  in 
many  ca^es,  we  have  fixed  the  minimum  amount  of  mercury  solution  neces- 
sary to-iidd  to  the  quantity  of  urine  in  question,  and  we  now  proceed  to  the 
:final  determination. 

A  second  quantity  of  the  filtrate,  corresponding  to  10  c.c.  of  the  original 
urine,  is  filtered,  and  the  same  quantity  of  mercury  solution  added  at  one 
time  as  was  found  necessary  to  produce  the  final  reaction,  and  immediately 
after  the  corresponding  amount  of  soda  solution,  which  must  not  indicate 
the  end  of  the  reaction.  Then  add  the  mercury  solution  in  Jy-  c.c.  without 
neutralizing  with  soda,  until  a  drop  taken  out  and  mixed  with  the  soda 
solution  gives  a  yellow  coloration.  If  this  final  reaction  is  obtained  after 
the  addition  of  0.1-0.2  c.c,  then  the  titration  may  be  considered  as  finished. 
If,  on  the  contrary,  a  larger  quantity  is  necessary,  the  addition  of  the 
mercury  solution  must  be  continued  until  a  final  reaction  is  obtained  with 
simple  carbonate,  and  the  titration  repeated  again,  adding  the  quantity  of 
mercury  solution  used  in  the  previous  test  at  one  time,  and  also  adding  the 
■corresponding  amount  of  soda  solution.  If  we  obtain  the  end  reaction  by 
(the  addition  of  -^j^  cc,  we  may  consider  the  titration  as  finished. 

If  in  each  titration  a  quantity  of  filtrate  containing  urine  and  baryta 
corresponding  to  10  c.c.  of  the  original  urine  is  used,  then  the  calculations 
are  very  simple,  since  1  c.c.  of  mercuric-nitrate  solution  corresponds  to  0.01 
grm.  of  urea.  As  the  mercury  solution  is  made  for  a  2^  urea  solution,  and  as 
the  filtrate  of  urine  and  baryta  generally  contains  less  urea  (if  the  quantity 
of  urea  is  above  2^,  it  is  easy  to  avoid  any  mistake  by  dilating  the  urine  at 
the  beginning  of  the  operation),  a  mistake  occurs  here  which  can  be 
corrected  in  the  following  way,  according  to  Pfluger:  To  the  measured 
volume  of  the  filtrate  from  the  urine  (the  filtrate  with  baryta  after  neutral- 
ization with  nitric  acid,  precipitation  with  silver  nitrate  and  filtration)  the 
quantity  of  normal  soda  solution  employed  is  added,  and  from  this  sum  the 
volume  of  mercury  solution  used  is  subtracted.     The  remainder  is  then 


MORNER  SJOqVIST  METHOD.  421 

multiplied  by  0.08,  and  the  product  subtracted  from  the  number  of  c.c.  of 
mercury  solution  used.  For  example,  if  the  filtrate  (urine  and  baryta 
+  nitric  acid  +  silver  nitrate)  measured  25.8  c.c,  and  the  number  of  c.c. 
of  soda  solution  used  in  the  titration  13.8  c.c,  and  the  mercury  solution 
20.5  cc,  we  have  then  20.5  -  J  (39.0  -  20.5)  X  0.08}  =  20.5  -  1.53  = 
18.07,  and  t1ie  corrected  quantity  of  mercury  solution  is  therefore  18.07  c.c. 
If  the  measured  c.c.  of  the  fdtrate  (in  this  case  25.8  c.c.)  corresponds  to 
10  c.c.  of  the  oriijinal  urine,  then  the  amount  of  nrea  is  18.07  X  0.01  = 
0.1807  =  18.07  p.m.  urea. 

Besides  the  urea  other  nitrogenous  constituents  of  the  urine  are  precipi- 
tated by  the  mercury  solution.  In  the  titration  we  really  do  not  obtain  the 
quantity  of  nrea,  but,  as  Pfluger  has  shown,  the  total  quantity  of  nitrogen 
in  tlie  urine  expressed  as  nrea.  As  urea  contains  40.07  p.  c  X,  the  total 
quantity  of  nitrogen  in  the  urine  may  be  calculated  from  the  quantity  of 
urea  found.  The  results  obtained  by  this  calculation  correspond  well, 
according  to  Pfluger,  with  the  results  found  for  the  total  nitrogen  as 
determined  by  K.jkldaiil's  method. 

Among  the  methods  suggested  for  the  special  estimation  of  urea,  that  of 
]M()RXKR-S.)0QvisT  is  perhaps  the  most  trustworthy  and  readily  performed. 
For  this  reason  this  method  only  will  be  given  in  detail,  while  we  must  refer 
to  special  works  for  the  other  methods,  such  as  Bunsek's  method  with  its 
many  modifications  as  suggested  by  Pfluger,  Bohlaxd  and  Bleibtreu.' 

Morner-Sjoqvist  Method.'  According  to  this  method  the  nitrogenous 
constituents  of  the  urine,  with  the  exception  of  the  urea  and  ammonia,  are 
first  precipitated  by  alcohol-ether  after  the  addition  of  a  solution  of  barium 
chloride  and  barium  hydrate,  and  then  the  urea  determined  in  the  concen- 
trated filtrate,  after  driving  off  the  ammonia,  by  Kjeldahl's  nitrogen 
estimation. 

The  procedure  is  as  follows:  ]Mix  5  c.c.  of  the  urine  in  a  flask  with 
5  c.c.  saturated  I5aCl,  solution,  in  which  5^  barium  hydrate  is  dissolved. 
Then  add  100  c.c.  of  a  mixture  of  two  parts  97^  alcohol  and  1  part  ether, 
and  allow  this  to  stand  in  the  closed  flask  overnight.  The  precipitate  is 
filtered  off  and  washed  with  alcohol-ether.  The  alcohol  and  ether  are 
removed  from  the  filtrate  by  distillation  at  about  55"  C.  (not  above  00°  C). 
Wiien  the  liquid  is  reduced  to  about  25  c.c.  a  little  water  and  calcined 
magnesia  are  added  and  the  evaporation  continued  until  the  vapors  are  no 
longer  alkaline  in  reaction,  Avhich  generally  is  found  before  it  is  concentrated 
to  15-10  c.c.  This  concentrated  liquid  is  transferred  into  a  proper  flask  by 
the  aid  of  a  little  water,  treated  with  a  few  drops  of  concentrated  sulphuric 
acid,  and  further  concentrated  on  the  water-bath.  Xow  20  c.c.  pure  con- 
centrated sulphuric  acid  is  added  and  the  process  carried  out  according  to 

K.IELDAIIL. 

Knop-IK'Fnek's  inetliocP  is  based  on  the  fact  that  urea,  by  thonction  of  sodimn  liypo- 
bromile,  splits  iuto  water,  carbon  dioxide  (which  dissolves  in  the  alkali),  and  nitrogen- 
whose  volume  is  measured  (see  page  416).  This  method  is  less  accurate  than  the  pre- 
ceding ones,  and  therefore  in  scientific  work  it  is  discarded.  It  is  of  value  to  the  phj'si- 
cian  and  for  practical  purposes,  because  of  the  ease  and  rapidity  witli  whicli  it  may  be 


'  Pflager's  Arch.,  Bdd.  38,  43,  and  44. 
»  Skand.  Arch.  f.  Physiol.,  Bd.  2. 

^  Knop,  Zeilschr.  f.  analyt.  Chem.,  Bd.  9  ;  Hiifner,  Jour.  f.  prakt.  Chem.  (N.  F.), 
Bd.  3.     See  also  Iluppert-Xeubauer,  10.  Aufl.,  S.  304,  etc. 


422  URINE. 

performed,  even  though  it  may  not  give  very  accurate  results.  For  practical  purposes 
ft  series  of  different  apparatus  have  been  constructed  to  facilitate  the  use  of  this  method. 
Among  these  Esbach's  ureometer  deserves  to  be  especially  mentioned,  and  also  Boht- 
lingk's  ■  apparatus. 

For  the  quantitative  estimation  of  urea  in  blood  or  other  animal  fluids, 
as  well  as  in  the  tissues,  Schondorff  has  proposed  a  method  where  the 
proteids  and  extractives  are  first  precipitated  by  a  mixture  of  phospho- 
tnugstic  acid  and  hydrochloric  acid,  and  then  the  filtrate  made  alkaline 
with  lime.  The  quantities  of  ammonia  formed  on  heating  a  part  of  this 
filtrate  to  150°  C.  with  phosphoric  acid,  and  the  quantity  of  carbon  dioxide 
produced  by  heating  the  other  part  to  150°  C.  are  determined.  In  regard 
to  the  principles  of  this  method,  as  well  as  to  the  details,  we  refer  to  the 
original  article  (Pfluger's  Arch.,  Bd.  62), 

Carbamic  Acid,  HaN.COOH.  This  acid  is  not  known  in  the  free  state,  but  only  as 
salts.  Ammonium  carbamate  is  produced  by  the  action  of  dry  ammonia  on  dry  carbon 
dioxide.  Carbamic  acid  is  also  produced  by  the  action  of  potassium  permanganate  on 
proteid  and  several  other  nitrogenous  organic  bodies. 

We  have  already  spoken  of  the  occurience  of  carbamic  acid  in  human  and  animal 
urines  in  connection  with  the  formation  of  urea.  The  calcium  salt,  which  is  soluble  in 
water  and  ammonia  but  insoluble  in  alcohol,  is  most  important  in  the  detection  of  this 
acid.  The  solution  of  the  calcium  salt  in  water  becomes  cloudy  on  standing,  but  much 
quicker  on  boiling,  and  calcium  carbonate  separates,  NoLF^  has  recently  made  investi- 
gations on  the  formation  and  detection  of  carbamic  acid. 

Carbamic  acid  et/iylester  (urethan),  as  shown  by  Japfe,'  may  pass,  by  the  mutual 
action  of  i/lcohol  and  urea,  into  the  alcoholic  extract  of  the  urine  when  working  with 
large  quantities  of  urine. 

Creatinin,  0,11,^3  0,  or  NH  :  C<r -j^.^j.  \  r<TT  ?   is  generally  considered 

■as  the  anhydride  of  creatin  (see  page  339)  found  in  the  muscles.     It  occurs 

in  human  urine  and  in  that  of  certain  mammalia.     It  has  also  been  found 

in  ox-blood,  milk,  though  in  very  small  amounts,  and  in  the  flesh  of  certain 

.fishes. 

Johnson's  statement  tbat  the  creatinin  of  the  urine  is  different  from  tlint  produced  by 
the  action  of  acids  on  creatin  is  incorrect  according  to  Toppelius  and  Pommerehne, 
WoERNEU  and  Thelen.'* 

The  quantity  of  creatinin  in  human  urine  is,  in  a  grown  man  voiding  a 
normal  quantity  of  urine  in  the  course  of  a  day,  O.G-1.3  grms.  (Neubauer), 
or  on  an  average  1  grm.  Johistson  '  found  1.7-2.1  grms.  per  day. 
The  quantity  is  dependent  on  the  food,  and  decreases  in  starvation.  Suck- 
lings do  not  generally  eliminate  any  creatinin,  and  it  only  appears  in  the 
urine  when  the  milk  is  replaced  by  other  food.  The  quantity  of  creatinin 
in  urine  varies  as  a  rule  with  the  quantity  of  urea,  although  it  is  increased 
more  by  meat  (because  the  meat  contains  creatin)  than  by  proteid.    Grocco 

'  In  regard  to  the  various  modifications  of  Knop-Hlifner's  method  see  Simon,  Clinical 
Diagnosis,  2d  ed. ;  also  Bohtlingk,  Arch.  exp.  de  St.  Petersbourg,  Tome  C. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  23. 

^  Ibid.,  Bd.  14. 

*  S.  .Johnson,  Proceed.  Roy.  Soc,  "Vols.  42,  43  ;  Chem.  News,  Vol.  55 ;  Toppelius  and 
Pommereline,  Arcii.  f.  Pluirm.,  Bd.  234  ;  Woerner,  Du  Bois-Reymond's  Arch.,  1898. 
.  •Huppert-Xeubaucr,  Ilarnaualyse,  10.  Aufl.,  S.  387. 


CREA  TININ.  423 

and  MoiTESSiER  claim  that  the  elimination  of  creatinin  is  increased  by 
mnscnlar  activity,  but  according  to  Oddi  and  Tahulli  '  this  is  only  true 
for  excessive  activity.  The  behavior  of  creatinin  in  disease  is  little  known. 
By  increased  metabolism  the  amount  is  increased,  while  by  decreased 
exchange  of  material,  as  in  anaemia  and  cachexia,  it  is  diminished. 

Creatinin  crystallizes  in  colorless,  shining  monoclinic  prisms  which  differ 
from  creatin  crystals  in  not  becoming  white  with  loss  of  water  when  heated 
to  100°  C.  It  dissolves  in  11  parts  cold  water,  but  more  easily  in  warm 
■water.  It  is  difficultly  soluble  in  cold  alcohol,  but  the  statements  in  regard 
to  its  solubilities  differ  widely.'  It  is  more  soluble  in  warm  alcohol.  It 
is  nearly  insoluble  in  ether.  In  alkaline  solution  creatinin  is  converted 
into  creiitin  very  easily  on  warming. 

Creatinin  gives  an  easily  soluble  crystalline  combination  with  hydro- 
chloric acid.  A  solution  of  creatinin  acidified  with  mineral  acids  gives 
crystalline  precipitates  with  phospho-tnngstic  or  phospho-molybdic  acids 
even  in  very  dilute  solutions  (1  :  10,000)  (Kerxer,  IIofmeister').  It  is 
precipitated,  like  urea,  by  mercuric-nitrate  solution  and  also  by  mercuric 
chloride.  On  treating  a  dilute  creatinin  solution  with  sodium  acetate  and 
then  with  mercuric  chloride  a  precipitate  of  glassy  globules  having  the 
composition  ■4(CJI,X30.nCl.IIgO)3IIgCl^  separates  on  standing  some  time 
^Johxson).  Among  the  compounds  of  creatinin,  that  with  zinc  chloride, 
creatinin  zinc-cJ/Ioride,  (C\II,X30)^ZnCl,,  is  of  special  interest.  This  com- 
bination is  obtained  when  a  sufficiently  concentrated  solution  of  creatinin  in 
alcohol  is  treated  with  a  concentrated,  faintly  acid  solution  of  zinc  chloride. 
Free  mineral  acids  dissolve  the  combination,  hence  they  must  not  be  present; 
this,  however,  may  be  prevented,  when  they  are  present,  by  an  addition  of 
sodium  acetate.  In  the  impure  state,  as  ordinarily  obtained  from  urine, 
creatinin  zinc  chloride  forms  a  sandy,  yellowish  powder  which  under  the 
microscope  appears  as  fine  needles  forming  concentric  groups,  mostly  com- 
plete rosettes  or  yellow  balls  or  tufts,  or  grouped  as  brushes.  On  slowly 
crystallizing  or  when  very  pure,  more  sharply  defined  prismatic  crystals  are 
obtained.     This  combination  is  sparingly  soluble  in  water. 

Creatinin  acts  as  a  reducing  agent.  Mercuric  oxide  is  reduced  to 
metallic  mercury,  and  oxalic  acid  and  methylguanidin  (methyl uramin)  are 
formed.  Creatinin  also  reduces  copper  hydroxide  in  alkaline  solution, 
forming  a  colorless  soluble  combination,  and  only  after  continuous  boiling 
with  an  excess  of  copper  salt  is  free  suboxide  of  copper  formed.  Creatinin 
interferes  with  Trommer's  test  for  sugar,  partly  because  it  has  a  reducing 

'  Grocco,  see  Maly's  Jahresber.,  Bd.  16  ;  Moitessier,  ibid.,  Btl.  21  ;  Oddi  and  Tarulli, 
iind.,  Bd.  24. 

*  See  Huppert-Xeubauer,  10.  Aufl. ,  and  Hoppe-Seyler's  Handbuch,  6.  Aufl. 

*  Kerner,  Pfluger's  Arch.,  Bd.  2  ;  Hofmeister,  Zeitschr.  f.  physiol.  Chera.,  Bd.  5. 


424  URINE. 

action  and  partly  by  retaining  the  copper  suboxide  in  solution.  The  com- 
bination with  copper  suboxide  is  not  soluble  in  a  saturated-soda  solution, 
and  if  a  little  creatinin  is  dissolved  in  a  cold,  saturated-soda  solution  and 
then  a  few  drops  of  Fehling's  reagent  added,  a  white  floccnlent  combina- 
tion separates  after  heating  to  50-60°  C.  and  then  cooling  (v.  Maschke's  ' 
reaction).  An  alkaline  bismuth  solution  (see  Sugar  Tests)  is  not  reduced 
by  creatinin. 

If  we  add  a  few  drops  of  a  freshly  prepared  very  dilute  sodium  nitro- 
prusside  (sp.  gr.  1.003)  to  a  dilute  creatinin  solution  (or  to  the  urine)  and 
then  a  few  drops  of  caustic  soda,  a  ruby-red  liquid  is  obtained  which  quickly 
turns  yellow  again  (Weyl's^  reaction).  If  the  cooled  yellow  solution  is 
neutralized,  and  treated  with  an  excess  of  acetic  acid  a  crystalline  precipi- 
tate of  a  nitroso  compound  (C^H^lSr^OJ  of  creatinin  separates  on  stirring 
(Kramm").  If,  on  the  contrary,  the  yellow  solution  is  treated  Avith  an 
excess  of  acetic  acid  and  heated,  the  solution  becomes  first  green  and  then 
bine  (Salkowski  ') ;  finally  a  precipitate  of  Prussian  blue  is  obtained.  If  a 
solntion  of  creatinin  in  water  (or  urine)  is  treated  with  a  watery  solution  of 
picric  acid  and  a  few  drops  of  a  dilute  caustic-soda  solution,  a  red  coloration 
lasting  several  hours  occurs  immediately  at  the  ordinary  temperature,  and 
which  turns  yellow  on  the  addition  of  acid  (Jaffe's"  reaction).  Acetone 
gives  a  more  reddish-yellow  color.  Grape-sugar  gives  with  this  reagent  a 
red  coloration  only  after  heating. 

In  preparing  creatinin  from  urine  the  creatinin  zinc  chloride  is  first 
prepared  according  to  Neubauer's  °  method.  One  litre  or  more  of  urine 
is  treated  with  milk  of  lime  until  alkaline  and  then  CaCl^  solution  until  all 
the  phosphoric  acid  is  precipitated.  The  filtrate  is  evaporated  to  a  syrup- 
after  faintly  acidifying  with  acetic  acid  and  this  treated  while  still  warm 
with  97^  alcohol  (about  200  c.c.  for  each  litre  of  urine).  After  about  12 
hours  it  is  filtered  and  the  filtrate  treated  first  with  a  little  sodium  acetate 
and  then  Avith  an  acid-free  zinc-chloride  solution  of  a  specific  gravity  of 
1.20  (about  200  c.c,  for  each  litre  of  urine).  After  thorough  stirring 
it  is  allowed  to  stand  48  honrs,  the  precipitate  collected  on  a  filter  and 
Avashed  with  alcohol.  The  creatinin  zinc  chloride  is  dissolved  in  hot  water, 
boiled  with  lead  oxide,  filtered,  the  filtrate  decolorized  by  animal  charcoal, 
evaporated  to  dryness  and  the  residue  extracted  with  strong  alcohol  (which 
leaves  the  creatin  undissolved).  The  alcoholic  extract  is  evaporated  to  the 
point  of  crystallization,  and  the  crystals  purified  by  recrystallization  from 
water. 

Creatinin   may   also   be    prepared   from   urine    by   precipitating   with 

'  Zeitschr.  f.  aualyt.  Clieni.,  Bd.  17. 

*  Ber.d.  deutsch.  cbem.  Gcsollsch.,  Bd.  11. 
»  Centralbl.  f.  d.  mcd.  Wisscnsch.,  1897. 

*  Zeitsclir.  f.  physiol.  Clicin.,  Bd.  4,  S.  133. 
s  Ihid.,  Bd.  10. 

«  Ann.  d.  Cbcm.  u.  Pliiirm.,  Bd.  119. 


ESTIMATION  OF  CREATININ.  425 

mercnric-chloride    solntiou   according   to    either   ^Ealy's   or   .Toiixson's 
process. 

Tlie  quantitative  estimation  of  creatinin  may  be  performed  according  to 
Neuhaueh's  method  for  the  preparation  of  creatinin,  or  more  simply  by 
Salkowski's  ''  modification  ol"  tliis  method.  240  c.c.  of  tlie  urine  freed  from 
proteid  (by  boiling  with  acid)  and  from  sugar  (by  fermentation  with  yeast) 
are  alkalized  with  milk  of  lime,  and  precipitated  by  CaCl,^  and  fdled  up  to 
300  c.c.  250  c.c.  {=  200  c.c.  urine)  are  measured  off,  neutralized  or  made 
only  faintly  acid  with  acetic  acid  and  evaporated  to  about  20  c.c,  then 
thoroughly  stirred  with  an  ecpial  volume  of  absolute  alcohol,  and  then  com- 
pletely transferred  to  a  100-c.c.  flask  which  contains  some  alcohol,  the 
residue  in  the  dish  being  washed  with  alcohol.  On  thorough  shaking  and 
cooling  the  flask  is  filled  to  the  100-c.c.  mark  with  absolute  alcohol  and 
allowed  to  stand  24  hours.  80  c.c.  (=  IGO  c.c.  urine)  of  the  filtrate  are 
collected  in  a  beaker-glass  and  treated  with  0.5-1  c.c.  zinc-chloride  solution, 
and  the  covered  beaker  is  left  standing  in  a  cool  place  for  two  or  three  days. 
The  precipitate  is  collected  on  a  small  dried  and  weighed  filter,  using  the 
filtrate  to  wash  the  crystals  from  the  beaker.  After  allowing  the  crystals  to 
comi)letely  drain  off,  they  are  Avashed  with  a  little  alcohol  until  the  filtrate 
gives  no  reaction  for  chlorine,  and  dried  at  100°  C.  100  parts  creatinin 
zinc-chloride  contain  G2.44  parts  creatinin.  As  the  precipitate  is  never 
quite  jnare,  the  quantity  of  zinc  must  be  carefully  determined,  in  exact 
experiments,  by  evaporating  with  nitric  acid,  heating,  washing  the  oxide  of 
zinc  with  water  (to  remove  any  NaCl),  drying,  heating,  and  weighing. 
22.4  parts  zinc  oxide  correspond  to  100  parts  creatinin  zinc  chloride. 

KoLiscH "  also  precipitates  Avith  milk  of  lime  and  CaCl, ,  filters,  makes 
the  filtrate  faintly  acid  with  acetic'acid,  evaporates  to  syrup,  and  extracts 
with  alcohol.  A  measured  volume  of  the  alcoholic  extract  is  precipitated 
with  an  alcoholic  solution  of  mercuric  cliloride  containing  acetic  acid.  The 
nitrogen  is  determined  by  Kjeldahl's  method  in  the  precipitate  carefully 
washed  with  absolute  alcohol  containing  a  little  sodium  acetate  and  a  few 
drops  of  acetic  acid.  On  multiplying  the  quantity  of  nitrogen  by  2.69  we 
obtain  the  quantity  of  creatinin.  The  mercuric  chloride  solution  consists 
of  30  parts  mercuric  chloride,  1  part  sodium  acetate,  3  drops  glacial  acetic 
acid,  and  125  parts  absolute  alcohol. 

Xanthocreatinin,  C5HioN40.  This  body,  which  was  first  prepared  from  meat  ex- 
tract by  Gautiek,  has  been  fouud  by  Monari  in  dog's  urine  after  the  injection  of 
cre.itinin  into  the  abdominal  cavity,  and  in  human  urine  after  several  hours  of  exliaust- 
ing  marching.  According  to  Colasantf  it  occurs  to  a  relatively  greater  extent  in  lion's 
urine.  Stadtiiagen^  considers  the  xanthocreatinin  isolated  from  human  urine  after 
strenuous  muscular  activity  as  impure  creatinin. 

Xanthocreatinin  forms  thin  sulphur-yellow  plates,  similar  to  cholesterin,  which  have 
a  bitter  taste.  It  dissolves  in  cold  water  and  in  alcohol,  and  gives  a  crystalline  combi- 
nation with  hy<Irochloric  acid  and  a  double  compound  with  gold  and  platinum  chloride. 
It  gives  a  coml)ination  witii  zinc  chloride,  which  crystallizes  in  tine  needles.  Xantho- 
creatinin has  a  poisonous  action, 

'  Maly,  Annal,  d.  Chem.  u.  Pharm.,  Bd.  159:  Johnson,  Proceed.  Roy.  See,  Vol.  43. 

»  Zeitschr.  f.  i)liysiol.  Chem.,  Bdd.  10  and  14. 

'  Centralbl.  f.  innere  iMed.,  1895. 

*  Qautier,  Bull,  de  I'acad.  de  med.  (2),  Tome  5,  and  Bull,  de  la  Soc.  Chem.  (2),  Tome 
48;  Monari,  Maly's  Jahresber.,  Bd.  17;  Colasanti,  Arch.  ital.  d.  Biologic,  Tome  15, 
Fasc.  3  ;  Stadthagen,  Zeitschr.  f.  klin.  Med.,  Bd.  15. 


426  URINE. 

HN— CO 

I       I 
_  .     CO   C— NH 

TJric  Acid,  Ur,    C,H,N,0,.        |       ||     :r:^CO.     Uric  acid,  which  is  a 

HN—  C— NH 
diureid  of  a  trioxyacrylic  acid,  is  closely  allied  to  the  nuclein  bases  (see 
Chapter  Y)  and  may  be  designated  as  2,  6,  8  trioxypurin  (E.  Fischee). 

Uric  acid  has  been  synthetically  prepared  by  Horbaczewski  '  in  several  ways. 
On  fusing  urea  and  glj^cocoll,  uric  acid  is  formed  according  to  the  formula 
3CON,H4  +  CqHsNOs  =  C5H4N4O3  +  2H2O  +  3NH3 ,  and  in  this  reaction  hydantoin 
and  biuret  are  formed  as  intermediate  products.  He  also  obtained  uric  acid  on  heating 
trichlor-lactic  acid,  or  still  better  trichlor-lactic  acid-amid,  with  an  excess  of  urea.  If 
we  eliminate  from  the  reaction  the  numerous  by-products  (cyanuric  acid,  carbon 
dioxide  etc.),  then  this  process  may  be  expressed  by  the  formula  C3CI3H4O3N4- 
2CON.H4  =  C.H4N4O3  +  H,0  +  NH4CI  +  2HC1. 

E.  Fischer  and  Ach  ^  have  prepared  uric  acid  from  pseudouric  acid,  which  is  richer 
in  one  molecule  of  water  than  ordinary  uric  acid,  by  heating  to  145°  C.  with  oxalic  acid. 

On  strongly  heating  uric  acid  it  decomposes  with  the  formation  of 
UREA,  HTDROCTANic  ACID,  CYANURIC  ACID,  and  AMMOXiA.  On  heating 
with  concentrated  hydrochloric  acid  in  sealed  tubes  to  170°  C.  it  splits  into 
GLTCOCOLL,  CARBON  DIOXIDE,  and  AMMONIA.  By  the  action  of  oxidizing 
agents  splitting  and  oxidation  take  place,  and  either  monoureids  or  dinreids 
are  produced.  By  oxidation  with  lead  peroxide,  carbon  dioxide,  oxalic 
ACID,  UREA,  and  allantoin,  which  last  is  glyoxyldiureid,  are  produced 
(see  below).  By  oxidation  with  nitric  acid  in  the  cold  urea  and  a  mono- 
ureid,  the  mesoxalyl  urea,  or  alloxan,  are  obtained,  O^H^N^Oj  +  0 -f 
H  0  =  C^H,X,0^  +  (NHJjCO.  On  warming  with  nitric  acid,  alloxan 
yields  carbon  dioxide,  and  oxalyl  urea,  or  parabanic  acid,  CjE^N^O,.  By 
the  addition  of  water  the  parabanic  acid  passes  into  oxaluric  acid., 
C  H^X,0, ,  traces  of  which  are  found  in  the  urine  and  which  easily  split  into 
oxalic  acid  and  urea.  In  alkaline  solution  uric  acid  may,  by  taking  up  water 
and  oxygen,  be  transformed  into  a  new  acid,  uroxanic  acid,  C^H^N^O, , 
which  may  then  be  changed  into  oxonic  acid,  C^H^lSTjO,.' 

Uric  acid  occurs  most  abundantly  in  the  urine  of  birds  and  of  scaly 
amphibians,  in  which  animals  the  greater  part  of  the  nitrogen  of  the  urine 
appears  in  this  form.  Uric  acid  occurs  frequently  in  the  urine  of  carniv- 
orous mammalia,  but  is  sometimes  absent;  in  urine  of  herbivora  it  is 
habitually  present,  though  only  as  traces;  in  human  urine  it  occurs  in 
greater  but  still  small  and  variable  amounts.  Traces  of  uric  acid  are  also 
found  in  several  organs  and  tissues,  as  in  the  spleen,  lungs,  heart,  pancreas, 
liver  (especially  in  birds),  and  in  the  brain.  It  habitually  occurs  in  the 
blood  of  birds  (Meissner).     Traces  have  been  found  in  human  blood  under 


>  Monatshefte  f.  Chem.,  Bdd.  6  and  8.  See  also  Behrend  and  Roosen,  Ber,  d.  deutsch. 
Chem.  Gesellsch.,  Bd.  21,  S.  999. 

«  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  28. 

» See  Sundwik,  Zeitschr,  f.  physiol.  Chem.,  Bd.  2o. 


URIC  ACID.  427 

normal  conditions  (Abeles).  Under  patliological  conditions  it  occurs  to 
an  increased  extent  in  tlie  blood  in  pneumonia  and  nephritis  (v.  Jakscii  ' 
and  others),  but  also  in  leucannia  and  arthritis.  Uric  acid  also  occurs  in 
large  quantities  in  '*  cliaik-stones,"  certain  urinary  calculi,  and  in  guano. 
It  has  also  beeii  detected  in  the  urine  of  insects  and  certain  snails,  as  also 
in  the  wings  (which  it  colors  white)  of  certain  butterflies  (IIopkixs*). 

The  amount  of  uric  acid  eliminated  with  human  urine  is  subject  to 
considerable  individual  variation,  but  amounts  on  an  average  to  0.7  grm. 
per  day  on  a  mixed  diet.  The  ratio  of  uric  acid  to  urea  varies  consider- 
ably with  a  mixed  diet,  but  is  on  an  average  1  :  50-1  :  70.  In  new-born 
infants  and  in  the  first  days  of  life  the  elimination  of  uric  acid  is 
increased  (Mares),  and  the  relation  between  uric  acid  and  urea  is 
about  1  :  13-14.  Sjoqvist  '  found  the  relationship  in  new-born  infants  to 
be  1  :  G. 43-17.1. 

In  regard  to  the  action  of  food  we  know  from  the  observations  of 
KA.XKE,  Mares,  and  others  that  the  elimination  of  uric  acid  is  diminished 
in  starvation,  and  that  it  quickly  increases  on  partaking  food,  especially 
proteid  food.  Mares  found  the  minimum  about  13  hours  after  the  last 
meal,  and  a  strong  increase  about  2-5  hours  after  meat  diet.  This  increase 
after  a  meal  rich  in  proteid  Horbaczewski  explains  by  the  digestion 
leucocytosis  (see  below)  which  habitually  appears.  It  is  quite  generally 
accepted  that  the  quantity  of  uric  acid  eliminated  with  vegetable  food  is 
smaller  than  wnth  a  meat  diet,  in  which  case  the  quantity  may  rise  to 
2  grms.  or  over  per  day.* 

The  statements  in  regard  to  the  influence  of  other  circumstances,  as  also 
of  different  bodies,  on  the  elimination  of  uric  acid  are  rather  contradictory. 
This  is  in  part  due  to  the  fact  that  the  older  investigators  used  an  inaccurate 
method  (IIeintz's  method),  and  also  that  the  extent  of  nric-acid  elimina- 
tion  is   dependent  in  the  first  place  upon  the  individuality.     Thus   the 


'  Meissner,  Zeitschr.  f.  rat.  Med.  (3),  Bd.  31,  cited  from  Hoppe-Seyler's  Physiol. 
Obein.,  S.  433;  Abeles,  Wieu.  mod.  Jahrblicher,  1S87,  cited  from  Maly's  Jahresber., 
Bd.  17;  V.  Jakscb,  Ueber  die  kliri.  Bedeuluiig  des  Vorkoiinnens  der  Flarnsaure,  etc. 
(Prager  Festsclirift,  Berlin,  1890,  S.  79)  ;  also  Zeitschr.  f.  Hcilkuudc.  Bd.  11,  and  Cen- 
tralbl.  f.  innere.  Med.,  1896.     See  also  Klemperer,  Deutsch.  ined.  Wocheuschr.,  1895. 

"  Philos.,  Trans   Roy.  Soc,  Vol.  186,  p.  661. 

*  A  very  good  tabular  summary  of  the  variation  in  the  elimination  of  uric  acid,  and 
the  ratio  of  total  nitrogen  to  uric-acid  nitrogen,  is  found  in  v.  Noorden's  Lehrbuch  der 
Pathologie  dcs  Stoffwechscls,  1893,  S.  54  ;  see  also  Mares  Centmlbl.  f.  d.  med.  Wis- 
seusch.  1888  ;  Sjoqvist,  Nord.  med.  Arkiv.  1894. 

*  J.  Rauke,  Beobachtungen  und  Versuche  liber  die  Ausscheidung  dor  Harnsaure,  etc. 
(Milnchen,  1858);  Mares,  1.  c;  Horbaczewski,  Wien.  Sitzuugsber.,  Bd.  100,  Abth.  3, 
1891.  In  regard  to  the  action  of  various  diets  the  reader  is  referred  to  the  above-cited 
authors,  and  especially  to  A.  Hermann,  Arch.  f.  klin.  Med.,  Bd.  43,  and  Camerer,  Zeit- 
schr. f.  Biologie,  Bd.  33. 


428  URINE. 

statements  in  regard  to  the  action  of  drinking-water'  and  of  alkalies'  are 
Tery  contradictory.  Certain  medicines,  such  as  quinin  and  atropin^ 
diminish,  while  others,  snch  as  pilocar^Din  and  also,  as  it  seems,  salicylic 
acid,'  increase,  the  elimination  of  uric  acid.  According  to  Horbaczeaa'ski  ^ 
and  his  pupils  the  first  cause  a  diminution  of  the  number  of  leucocytes  in 
the  blood,  while  the  last  cause  an  increase  in  the  number. 

Little  is  known  with  positiveness  in  regard  to  the  elimination  of  uric 
acid  in  disease.  In  acute,  critical  diseases  the  elimination  of  uric  acid  is 
increased  after  the  crisis;  while  the  older  statements  that  the  uric  acid  is 
habitually  increased  in  fevers  has  been  contradicted  by  many,^  The  state- 
ments in  regard  to  the  elimination  of  urea  in  gout"  and  nephritis'  are  also 
uncertain  and  contradictory.  In  leucaemia  the  elimination  is  increased 
absolutely  as  well  as  relatively  to  the  urea  (Eanke,  Salkoavski,  Fleischer 
and  Pextzoldt,  Stadthagen^,  Sticker,  Bohlais'd  and  Schurz,'  and 
others),  and  the  relationship  between  the  uric  acid  and  urea  (total  nitrogen 
recalculated  as  urea)  may  be  even  1  :  9,  while  under  normal  conditions, 
according  to  different  investigators,  it  is  1  :  40  to  66  to  100. 

Formation  of  Uric  Acid  in  tlie  Organism.  The  formation  of  uric  acid 
in  birds  is  increased  by  the  administration  of  ammonia-salts  {y.  Schroder). 
I'rea  4cts  in  the  same  Avay  (Meyer  and  Jaffe),  while  in  the  organism  of 
mammalia  uric  acid  is  more  or  less  completely  converted  into  urea,  as  shown 
by  WoHLER  and  Frerichs  "  on  dogs.  Minkoavski  observed  in  geese  with 
extirpated  livers  a  very  significant  decrease  in  the  elimination  of  uric  acid, 
while  the  elimination  of  ammonia  was  increased  to  a  corresponding  degree. 
This  indicates  a  participation  of  ammonia  in  the  formation  of  uric  acid  in 
the  organism  of  birds;  and  as  Minkoaa^ski  has  also  found  after  the  extirpa- 


'  See  Schondorflf,  Pflliger's  Arch.,  Bd.  46,  which  contains  the  pertinent  literature. 

»  See  Clar,  Cenlrulbl.  f.  d.  med.  Wissensch.,  1888  ;  Haig,  Journ.  of  Physiol.,  Vol. 
8;  and  A.  Hermann,  Arch.  f.  kliu.  Med.,  Bd.  43. 

*  See  Bohland,  cited  from  Maly's  Jahresber.,  Bd.  26. 

^Wien.  Sitzungsber.,  Bd.  100. 

'  See  v.  Noorden,  Lehrbuch.  S.  211  and  212  ;  Kiihuau,  Zeitschr.  f.  klin.  Med.,  Bd. 
28  ;  Dunin  and  Nowaczck,  ibid.,  Bd.  32. 

«See  Laqner,  "  Uber  die  Ausscheidungsverhaltuisseder  Alloxurkorper,"  Wie.sbaden, 
1896;  E.  PfeifTer,  Berlin  klin.  Wochenschr.,  1896;  Magnus-Levy,  ibid.;  Malfatti, 
Wien.  klin.  Wochenschr.,  1896;  His,  Wien.  med.  BUltter,  1890. 

■'  See  V.  .Taksch,  Zeit.schr.  f.  lieilkunde,  Bd.  11,  and  Centralbl,  f.  innere  Med.,  1896; 
Kolisch  and  Dostal,  Wien.  klin.  Wociiensclir.,  1895  ;  Geza  Fodor,  Maly's  Jahresber., 
Bd.  25;  Zuelzer,  Berlin,  klin.  Wochenschr.,  1896. 

8  Ranke,  see  Schmidt's  Jaiirb.,  1859;  Salkowski,  Virchow's  Arch.,Bd.  50;  Fleischer 
and  Pentzoldt,  Arch.  f.  klin.  Med.,  Bd.  26;  Stadthageii,  Virchow's  Arch.,  Bd.  109; 
Sticker,  Zeitschr.  f.  klin.  Med.,  Bd.  14  ;  Bohland  and  Schurz,  Plluger's  Arch..  Bd.  47. 

»  V.  Schroder,  Zeitschr.  f.  physiol.  Chem.,  Bd.  2;  Meyer  and  Jaffe,  Ber.  d.  deutsch. 
chcm.  Gesellsch.,  Bd.  10;  Wohler  and  Frerichs,  Annal.  d.  Chem.  u.  Pharm.,  Bd.  65. 


FORMATION  OF   UlilC  ACID.  429 

tioii  of  the  liver  that  considerable  iuuouiitri  of  lactic  acid  occur  in  the  urine, 
it  is  probable  that  the  uric  acid  in  birds  is  produced  in  the  liver,  perha])s 
from  lactic  acid  and  ammonia  by  svnthesis.  Amido-acids — leucin,  glvco- 
coll,  and  aspartic  acid — increase  the  elimination  of  uric  acid  in  birds 
(v.  Knieriem),  but  whether  the  amido-acids  are  first  decom]josed  with  the 
splitting  off  of  ammonia  is  still  unknown,  v.  Mach  '  has  siiown  that  a 
small  part  of  the  uric  acid  in  birds  originates  from  hypoxanthin,  and  a 
similar  origin  for  the  uric  acid  of  mammalia  is  also  very  probable  (Mi\- 
KOWSKi).  Independently  of  Cohn',  Minkowski'  has  observed  a  consider- 
able increase  in  the  allantoin  of  the  urine  in  dogs  after  feeding  with  thymus. 
JS.VLKOwsKi'  has  made  similar  observations  on  dogs  after  feeding  with 
pancreas. 

AVe  have  no  foundation  for  the  assumption  that  uric  acid  is  formed  from 
ammonium  salts  in  the  human  and  the  mammalian  liver.  On  the  contrary, 
the  formation  of  uric  acid  seems  to  stand  in  a  certain  relationship  to  the 
nucleus  nucleins.  IIorhaczewski*  has  prepared  uric  acid  from  tissues  rich 
in  nuclein,  such  as  the  spleen-pulp,  and  from  spleen  nuclein  by  slight  putre- 
faction, subsequent  oxidation  with  blood,  and  then  cleavage  by  boiling.  If 
the  oxidation  was  neglected,  he  obtained  an  equivalent  quantity  of  xanthin 
bodies.  The  nuclein  prepared  from  the  spleen-pulp  when  introduced  into 
the  animal  body  causes  an  increase  in  the  elimination  of  uric  acid,  and, 
according  to  the  experience  of  many  investigators,' feeding  with  the  thymus, 
which  is  very  rich  in  nucleins,  has  the  same  action.  According  to  IIor- 
BACZEWSKI  the  uric  acid  is  not  formed  from  the  alloxuric  bases  as  in- 
termediary steps,  but  all  alloxuric  bodies  are  derived  from  the  nucleins — 
the  uric  acid  when  cleavage  precedes  an  oxidation,  and  the  alloxuric  bases 
with  cleavage  without  oxidation. 

The  recent' very  important  researches  of  Minkowski'  have  further 
shown  that  a  synthetical  formation  of  uric  acid  from  ammonium  compounds 
in  dogs  is  very  improbable.  He  also  shows  that  when  allantoin  is  adminis- 
tered to  dogs  the  greater  part  appears  unchanged  in  the  urine,  while  in  man 
hardly  one  fifth  could  be  regained.  After  feeding  dogs  with  nucleins  the 
quantity  of  allantoin  as  well  as  the  quantity  of  uric  acid  must  be  consid- 

'  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharui.,  Bd.  21  ;  v.  Knieriem,  Zeitschr.  f. 
Biologic,  Bd.  13;  v.  Mach,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24. 

»  Ceutralbl.  f.  innere  Med.,  1898. 

»  Centralbl.  f.  d.  med.  Wissensch.,  1898. 

MVieu.  Sitzuugsber..  Bd.  100. 

'  See  Weiulraud,  Berlin,  kliu.  "Wochenschr.,  1895,  and  Du  Bois-Reymond's  Arch.. 
1895;  Umber.  Zeitschr.  f.  klin.  Med.,  Bd.  29;  P.  Mayer.  Deutsch.  med.  "Wochenschr., 
1896;  Jerome,  Journ.  of  Physiol.,  Vol.  22  ;  Heiss  and  SchmoU,  Arch.  f.  exp.  Path.  u. 
Pharm.,  Bd.  37. 

•  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  41. 


430  URINE. 

ered.  Although  the  thymus  nucleins  considerably  increase  the  quantity  of 
allantoin  and  uric  acid,  the  nuclein  bases,  "with  the  exception  of  hypo- 
xanthin,  split  off  from  these  nucleins  are  inactive.  Salmon  nucleic  acid 
also  causes  an  increased  elimination  of  uric  acid,  but  the  adenin  split  off 
therefrom  or  prepared  synthetically  does  not  have  this  action.  The  organic 
combinations  of  the  nuclein  bases  in  the  nucleins  seem  to  be  essential  for 
the  occurrence  of  allantoin  and  uric  acid  in  the  urine.  Hypoxanthin  taken 
per  OS  is  transformed  into  uric  acid  in  human  beings,  and  into  uric  acid  and 
allantoin  in  dogs.  Adenin,  \vhich  in  dogs  does  not  cause  an  increased  elimi- 
nation of  uric  acid  and  allantoin,  has  a  poisonous  action  and  leads  to  the 
abundant  deposition  in  the  kidneys  of  spheroliths,  which  contain  uric  acid. 
A  deposition  of  uric  acid  in  the  kidneys  may  occur  independently  of  the 
extent  of  uric-acid  elimination  by  the  urine. 

The  following  observations  of  Hopkins  and  Hope  '  can  hardly  be  recon- 
ciled with  MiNKOW^SKi's  investigations.  Apart  from  certain  other  obser- 
vations, which  do  not  speak  for  the  ordinary  view  as  to  the  formation  of  uric 
acid  from  the  nucleins  of  the  food,  they  find  that  on  digesting  thymus 
glands  with  gastric  juice,  the  neutralized  extract,  which  contains  only 
traces  of  nuclein  or  nuclein  bases,  has  a  strong  augmentative  action  on  the 
elimination  of  uric  acid,  while  the  remaining  nucleins  themselves  have  only 
a  slight  action. 

The  increased  elimination  of  uric  acid  after  the  introduction  of  nucleins 
into  the  animal  body  does  not  depend,  according  to  Horbaczewski,  directly 
upon  a  decomposition  of  nucleins.  According  to  him  it  may  be  due 
indirectly  to  the  leucocytosis  produced  by  the  nuclein.  According  to 
Horbaczewski  the  uric  acid  originates  chiefly  from  the  nuclein  of  the 
destroyed  leucocytes,  and  the  greater  the  number  of  leucocytes  in  the  blood 
the  greater  is  the  destruction  of  the  same,  and  hence  the  elimination  of  uric 
acid  is  correspondingly  increased.  Observations  on  the  elimination  of  uric 
acid  stand  in  close  accord  with  this  theory.  Thus,  for  example,  leucaemia^ 
in  which  the  elimination  of  uric  acid  is  greatly  increased,  is  characterized 
by  an  abnormally  great  number  of  leucocytes  in  the  blood.  Those  medica- 
ments which  increase  the  number  of  leucocytes  also  increase  in  general  the 
elimination  of  uric  acid." 

IIoRBACZEWSKi's  vicw  that  the  uric  acid  is  a  product  of  the  destruction 
of  the  leucocytes  is  generally  accepted.  According  to  Mares  no  positive 
proof  has  been  given  for  this.  It  has  not  been  proved  that  each  increase  in 
the  number  of  leucocytes  causes  an  increase  in  the  uric  acid  eliminated,  and 
in  fact  this  has  not  been  always  found  after  feeding  with  nuclein.' 

1  Journ.  of  Physiol.,  Vol.  23. 

'  For  expliinatiou  as  to  tbe  differing  behavior  of  antifebiin  and  autip3'iin  see  Horbac- 
zewski, 1.  c. 

'Mares,  "VVieu.  Sitzungsber.,  Bd.  101,  Abth.  3,  and  "Zur  Theorie  der  HarnsUure- 


PROPERTIES  Ayi)  REACTIONS  OF  URIC  ACID.  431 

We  cannot  say  anything  positive  in  regard  to  the  organ  or  organs  in 
which  nric  acid  is  formed. 

After  the  extirpation  of  the  kidneys  of  snakes  (Zaleski)  and  birds 
(v.  Sciiuodek')  an  accumnlation  of  nric  acid  in  the  blood  and  tissues  has 
been  observetL  This  shows  tluit  tlie  kidneys  of  these  animals  are  not  the 
only  organ  producing  uric  acid,  and  any  direct  proof  of  the  formation  of 
this  acid  in  the  kidneys  has  not  np  to  the  present  time  been  demonstrated. 
A  direct  relationship  between  the  spleen  and  the  formation  of  uric  acid 
in  man,  has  been  sought  by  several  investigators.  According  to  the  in- 
vestigations of  IIoRBACZEWSKi  this  relationship  seems  to  be  of  an  indirect 
kind,  as  it  probably  stands  in  close  connection  with  the  importance  of  the 
spleen  to  the  formation  of  the  leucocytes.  If  nric  acid  is  derived  in  man 
and  mammals,  as  generally  admitted,  chiefly  from  nuclein,  then  we  must 
look  for  its  formation  where  a  destruction  of  tissues  containing  nuclein 
takes  place,  even  though,  according  to  IIorbaczewski,  it  originates  in  the 
first  place  in  the  destruction  of  the  leucocytes.  We  have  no  positive  basis 
for  the  statement  that  uric  acid  is  formed  in  the  liver  of  man  and  mammals, 
while,  on  the  contrary,  the  formation  of  uric  acid  in  the  liver  of  birds  is 
shown  to  be  highly  probable  by  the  researches  of  Minkowski. 

According  to  the  investigations  of  Frerichs  and  Wuiiler  the  uric  acid 
introduced  into  a  mammal  organism  is  converted  in  great  part  into  urea, 
and  according  to  Wiener  glycocoll  in  rabbits  appears  as  an  intermediate 
step  in  the  destruction  of  uric  acid.  As  the  liver,  according  to  Salaskix 
and  LoEWi  (see  page  412)  can  produce  urea  or  closely  allied  substances 
from  glycocoll,  it  is  quite  possible  that  the  liver  is  an  organ  in  Avhich  uric 
acid  is  destroyed  with  the  formation  of  urea — an  assumption  which  coincides 
with  the  observations  of  Chassevant  and  Richet  '  and  of  Ascoli. 

Properties  and  Reactions  of  Uric  Acid.  Pure  nric  acid  is  a  white, 
odorless,  and  tasteless  powder  consisting  of  very  small  rhombic  prisms  or 
plates.  Impure  uric  acid  is  easily  obtained  as  somewhat  larger,  colored 
crystals. 

In  quick  crystallization,  small,  thin,  four-sided,  apparently  colorless, 
rhombic  prisms  are  formed,  which  can  be  seen  only  by  the  aid  of  the  micro- 
BcojDe,  and  these  sometimes  appear  as  spools  because  of  the  rounding  of  their 
obtuse  angles.     The  plates  are  sometimes  six-sided,  irregularly  developed; 

bildung  iin  Siiugethierorganistmis."  Prag,  1892.  See  also  Milroj' aud  Malcolm,  Journ 
of  Physiol.,  Vol.  23:  Gnmlich,  Zeitschr.  f.  physiol.  Chem.,  Bd.  18,  and  Stadthagen, 
Viicljow's  Arch.,  Bd.  109. 

'  Zaleski,  "  Untcrsuchungen  liber  deu  urami.«chen  Prozess  "  (Tubingen,  1865),  cited 
from  Hermann's  Ilmdbiich,  Bd.  5,  Thl.  1  ;  v.  Schroder,  Du  Bois-Reymond's  Arch., 
1880,  Suppl.  Bd.,  and  Ludwig's  Festschrift,  1887. 

*  Wiener,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  40  ;  Chassevant  and  Richet,  Compt, 
rend.  soc.  bid.,  Tome  49 ;  Ascoli,  Pflliger's  Arch.,  Bd.  72. 


432  URINE. 

in  other  cases  they  are  rectangalar  with  partly  straight  and  partly  jagged 
sides;  and  in  others  cases  they  show  still  more  irregular  forms,  the  so-called 
dumb-bells,  etc.  In  slow  crystallization,  as  when  the  urine  deposits  a  sedi- 
ment or  when  treated  with  acid,  large,  invariably  colored  crystals  separate. 
Examined  with  the  microscope  these  crystals  appear  always  yellow  or 
yellowish  brown  in  color.  The  most  ordinary  form  is  the  whetstone  shape, 
formed  by  the  rounding  off  of  the  obtuse  angles  of  the  rhombic  plate.  The 
whetstones  are  generally  connected  together,  two  or  more  crossing  each 
other.  Besides  these  forms,  rosettes  of  prismatic  crystals,  irregular  crosses, 
brown-colored  rough  masses  of  destroyed  needles  and  prisms  occur,  as  well 
as  other  forms. 

Uric  acid  is  insoluble  in  alcohol  and  ether;  it  is  rather  easily  soluble  in 
boiling  glycerin,  very  difi&cultly  soluble  in  cold  water  (14,000-16,000  parts), 
and  difficultly  soluble  in  boiling  water  (in  1800-1900  parts).  In  water  at 
'40°  0.  it  dissolves  in  the  proportion  of  1  :  2400  (Smale).  Hydrochloric 
acid  dissolves  it  somewhat  better  than  water.  It  is  soluble  in  a  warm  solu- 
tion of  sodium  diphosphate,  and  in  the  presence  of  an  excess  of  uric  acid 
monophosphate  and  acid  urate  are  produced.  According  to  the  ordinary 
view,  sodium  diphosphate  is  also  a  solvent  for  the  uric  acid  in  the  urine, 
but  ac9<^rding  to  Smale  the  monophosphate  has  only  a  slight  solvent 
action.  According  to  Eudel  '  urea  is  an  important  solvent.  1000  c.c.  of 
a  2^  urea  solution  can  hold  on  an  average  0.529  grm.  uric  acid  in  solution, 
and  as  the  daily  quantity  of  urine  is  1500-2000  c.c,  and  this  contains  2^ 
nrea,  it  is  possible  for  the  urea  alone  to  hold  nearly  all  of  the  uric  acid 
eliminated  in  solution.  Uric  acid  is  not  only  dissolved  by  alkalies  and 
alkali  carbonates,  but  also  by  several  organic  bases,  such  as  ethylamin  and 
propylamin,  piperidin  and  piperazin.  Uric  acid  dissolves  without  decom- 
posing in  concentrated  sulphuric  acid.  It  is  completely  precipitated  from 
the  urine  by  picric  acid  (Jaffe  ').  Uric  acid  gives  a  chocolate-brown 
precipitate  with  phospho-tungstic  acid  in  the  presence  of  hydrochloric  acid. 

Uric  acid  is  dibasic  and  correspondingly  forms  two  series  of  salts, 
neutral  and  acid.  According  to  Bence  Jones'  hyperacid  salts,  quad- 
KiURATES,  with  the  general  formula  CJIjMN.Oj.CJI^N^O,  ,  occur. 

Of  the  alkali  urates  the  neutral  potassium  and  lithium  salts  dissolve 
most  easily,  and  the  ammonium  salt  dissolves  with  difficulty.  The  acid- 
alkali  urates  are  very  insolu-ble,  and  separate  as  a  sediment  {sedimentum 
lateritium)  from  concentrated  urine  on  cooling.  The  salts  with  alkaline 
earths  are  very  insoluble. 

If  a  little  uric  acid  in  substance  is  treated  on  a  porcelain  dish  with  a 

'  Smale,  Centralbl.  f.  Physiol.,  Bd.  9  ;  Rtidel,  Arch.  f.  exp.  Path.  u.  Pharrn.,  Bd.  30. 

'  Zcitschr.  f.  pbysiol.  Chem.,  Bd.  10. 

'  Jouru.  Chem.  See,  1862,  Vol.  15,  p.  8.         ' 


QUANTITATIVE  ESTIMATION  OF  URIC  ACID.  433 

few  drops  of  nitric  acid,  the  uric  acid  dissolves  on  warming  with  a  strong 
development  of  gas,  and  after  thoroughly  drying  on  the  water-batli  a 
beautiful  red  residue  is  obtained,  which  turns  a  purple-red  (ammonium 
purpurate  or  murexide)  on  the  addition  of  a  little  ammonia.  If,  instead  of 
the  ammonia,  we  add  a  little  caustic  soda  (after  cooling),  the  color  becomes 
deeper  blue  or  bluish  violet.  This  color  disappears  quickly  on  warming, 
differing  from  certain  xanthin  bodies.  This  reaction  is  called  the  murexide 
test. 

If  nric  acid  is  converted  into  alloxan  by  the  careful  action  of  nitric  acid 
and  the  excess  of  acid  carefully  expelled  on  treating  this  with  a  few  drops 
of  concentrated  sulphuric  acid  and  commercial  benzol  (containing  thiophen), 
a  beautiful  blue  coloration  is  obtained  (Deniges'  '  reaction). 

Uric  acid  does  not  reduce  an  alkaline  solution  of  bismuth,  while,  on  the 
contrary,  it  reduces  an  alkaline  copper-hydroxide  solution.  In  the  presence 
of  only  a  little  copper  salt  we  obtain  a  white  precipitate  consisting  of  copper 
urate.  In  the  presence  of  more  copper  salt  red  suboxide  separates.  The 
combination  of  uric  acid  with  copper  suboxide  is  formed  when  copper  salts 
are  reduced  in  alkaline  solution  in  the  presence  of  urate  by  glucose  or 
bisulphite. 

If  a  solution  of  uric  acid  in  water  containing  alkali  carbonate  is  treated 
with  magnesium  mixture  and  then  a  silver-nitrate  solution  added,  a  gelatin- 
ous precipitate  of  silver-magnesium  urate  is  formed.  If  a  drop  of  uric  acid 
dissolved  in  sodium  carbonate  is  placed  on  a  piece  of  filter-paper  which  has 
been  previously  treated  with  silver-nitrate  solution,  a  reduction  of  silver 
oxide  occurs  producing  a  brownish-black  or,  in  the  presence  of  only  0.002 
milligramme  uric  acid,  a  yellow  spot  (Schiff's  test). 

Preparation  of  Uric  Acid  from  Urine.  Filtered  normal  urine  is  treated 
with  20-30  c.c.  of  'Ibfo  hydrochloric  acid  for  each  litre  of  urine.  After 
forty-eight  hours  collect  the  crystals  and  purify  them  by  redissolving  in 
dilute  alkali,  decolorizing  with  animal  charcoal  and  reprecipitating  with 
hydrochloric  acid.  Large  quantities  of  uric  acid  are  easily  obtained  from 
the  excrements  of  serpents  by  boiling  them  with  dilute  caustic  potash  {b%) 
until  no  more  ammonia  is  developed.  xV.  current  of  carbon  dioxide  is  passed 
through  the  filtrate  until  it  barely  has  an  alkaline  reaction;  dissolve  the 
separated  and  washed  acid  potassium  urate  in  caustic  potash,  and  precijDitate 
the  uric  acid  by  addition  of  an  excess  of  hydrochloric  acid  to  the  filtrate. 

Quantitative  Estimation  of  Uric  Acid  in  the  Urine.  As  the  older 
method  as  suggested  by  IIeintz,  even  after  recent  modifications,  gives 
inaccurate  results,  we  will  not  give  it  in  detail. 

Salkowski  and  Ludwig's*  method  consists  in  precipitating  by  silver 

'  Journal  de  Pharm.  et  de  Cbim.,  Tome  18.  Cited  from  Maly's  Jabresber.,  Bd.  18, 
S.  24. 

'  Salkowski,  Virchow's  Arch.,  Bd.  52,  PflUger's  Arch.,  Bd.  5,  and  Practicum  der 
physiol.  u.  patbol.  Cbem.,  Berlin,  1893;  Ludwig,  Wien.  med.  Jahrbucb,  1S84,  and  Zeii- 
schr.  f.  anal.  Cbem.,  Bd.  24. 


434  .        URINE. 

nitrate  the  nric  acid  from  the  nrine  previously  treated  with  magnesia 
mixtnre,  and  weighing  the  nric  acid  obtained  from  the  silver  precipitate. 
Uric-acid  determinations  by  this  method  are  often  performed  according  to 
the  snggestion  of  E.  Ludwig,  -which  requires  the  following  solutions: 

1.  An  AMMONIACAL  SILVER-NITRATE  SOLUTION,  Avhicli  coutains  ill  oue  litre  26  grms. 
silver  uiliate  aud  a  quantity  of  amuiouia  sufficient  to  completely  ledissolve  the  precipi- 
tate produced  by  the  first  addition  of  ammonia.  2.  Magnesia  mixture.  Dissolve 
100  grms.  crystallized  magnesium  chloride  in  water  aud  add  enough  ammonia  so  that 
the  liquid  smells  strongly  of  it,  and  enough  ammonium  chloride  to  dissolve  the  precipi- 
tate and  dilute  to  1  litre.  3.  Sodium- sulphide  solution.  Dissolve  10  grms.  caustic 
soda  which  is  free  from  nitric  acid  and  nitrous  acid  in  1  litre  of  water.  One  half  of 
this  solution  is  completely  saturated  with  sulphuretted  hydrogen  and  then  mixed  with 
the  other  half. 

The  concentration  of  the  three  solutions  is  so  arranged  that  10  c.c.  of 
each  is  sufficient  for  100  c.c.  of  the  urine. 

100-200  c.c,  according  to  concentration,  of  the  filtered  nrine  freed 
from  proteid  (by  boiling  after  the  addition  of  a  few  drops  of  acetic  acid)  is 
poured  into  a  beaker.  In  another  vessel  mix  10-20  c.c.  of  the  silver  solu- 
tion with  10-20  c.c.  of  the  magnesia  mixture  and  add  ammonia,  and  when, 
necessary  also  some  ammonium  chloride,  until  the  mixture  is  clear.  This 
solution  is  added  to  the  nrine  while  stirring,  and  the  mixture  allowed  to 
stand  quietly  for  half  an  hour.  The  precipitate  is  collected  on  a  filter, 
washed  with  ammoniacal  water,  and  then  returned  to  the  same  beaker  by 
the  aid  of  a  glass  rod  and  a  wash-bottle,  without  destroying  tLe  filter. 
jS'ow  h^t  to  boiling  10-20  c.c.  of  the  alkali-sulphide  solution,  which  has 
previously  been  diluted  with  an  equal  volume  of  water,  and  allow  this  solu- 
tion to  flow  through  the  above  filter  into  the  beaker  containing  the  sliver 
precipitate,  wash  with  boiling  water,  and  warm  the  contents  of  the  beaker 
on  a  water-bath  for  a  time,  stirring  constantly.  After  cooling  filter  into  a 
porcelain  dish,  wash  with  boiling  water,  acidify  the  filtrate  with  hydro- 
chloric acid,  evaporate  to  about  15  c.c,  add  a  few  drops  more  of  hydro- 
chloric acid,  and  allow  it  to  stand  for  24  hours.  The  uric  acid  which  has 
crystallized  is  collected  on  a  small  weighed  filter,  washed  with  water, 
alcohol,  ether,  and  carbon  disulphide,  dried  at  100-110°  C.  and  weighed. 
For  each  10  c.c  of  watery  filtrate  we  must  add  0.00048  grm.  uric  acid  to 
the  quantity  found  directly.  Instead  of  the  weighed  filter-paper  a  glass 
tube  filled  with  glass-wool  as  described  in  other  handbooks  may  be  substi- 
tuted (Ludwig).  Too  intense  or  continuous  heating  with  the  alkali  sulphide 
must  be  prevented,  otherwise  a  part  of  the  nric  acid  may  be  decomposed. 

Salkowski  differs  from  this  procedure  by  precipitating  the  urine  first 
with  a  magnesia  mixture  (50  c.c.  to  200  c.c.  nrine),  filling  up  to  300  c.c. 
and  filtering.  The  filtrate,  200  c.c,  is  precipitated  by  10-15  cc  of  a  3^ 
ailver-nitrate  solution.  The  silver  precipitate  is  shaken  with  200-300  c.c. 
water  acidified  with  a  few  drops  of  hydrochloric  acid,  decomposed  by  sul- 
phuretted hydrogen,  heated  to  boiling,  the  silver-sulphide  precipitate  boiled 
with  fresh  water,  filtered,  concentrated  to  a  few  cubic  centimetres,  treated 
with  5-8  drops  of  hydrochloric  acid,  and  allowed  to  stand  until  the  next  day. 

Hopkins's  '  method  is  based  on  the  fact  that  the  uric  acid  is  comi^letely 
precipitated  from  the  nrine  as  ammonium  urate  on  saturating  with  am- 
monium chloride.     The  urine  is  saturated  with  ammonium  chloride   (for 

'  .Tourn.  of  Path,  and  Bacteriol.,  1893,  and  Proceed,  lloy.  Soc,  Vol.  52. 


XANTUIN  BODIES  OR  ALLOXUlilU  BASES.  435 

each  100  c.c.  urine  add  oO  grins,  auinionium  chloride),  and  llltered  after  two 
hours.  Wasli  witli  a  saturated  sohition  of  ainnioniuni  cliloride,  and  transfer 
the  precipitate  from  filter  to  a  small  beaker  by  means  of  boiling  water,  and 
deconqiose  it  with  hydrocldoric  acid  aiul  heat.  The  uric  acid  wdiich 
separates  is  weiglied  by  the  Lidwig-Halkowski  method,  and  for  every  15 
c.c.  of  niother-iiciuor  add  1  milligramme  to  the  weiglied  uric  acid.  The 
nric  acid  in  the  ammonium  urate  may  also  be  determined  by  titration  with 
potassium  permanganate,  but  the  contents  of  the  lilter  must  first  be  washed 
free  from  chlorine  by  Avashing  with  a  saturated  solution  of  ammonium 
sulphate.  The  precipitate  is  washed  off  from  the  filter  into  a  llask  with  hot 
water  (200  c.c),  and  allowed  to  cool  to  20°  C,  and  then  treated  with  15  c.c. 
concentrated  sulphuric  acid  (sp.  gr.   1.84).     The    mixture  attains  a  tem- 

peratnre  of  00-03°  C,  and  if  we  titrate  at  this  temperature  with  a  — 

potassium  permanganate  solution  each  cubic  centimetre  of  the  permanganate 
solution  corresponds,  according  to  FoLix,  to  exactly  3.75  milligrammes  uric 
acid.  Hopkins  obtained  also  3.75,  while  Rittkr,'  on  the  contrary,  obtained 
3.01  milligrammes  uric  acid.  lIoi'KiNs's  method  is  claimed  to  give  as  exact 
results  as  the  SALKOwsKi-LrmviG  method.  According  to  Folix  it  is  not 
necessary  to  saturate  the  urine  with  ammonium  salt,  but  this  is  denied  by 
others,  and  he  has  essentially  shortened  the  method  by  precipitating  with  a 
lOi;  ammonium  sulphate  solution. 

In  regard  to  the  various  modifications  of  the  above-described  methods, 
as  well  as  to  the  numerous  other  methods  for  estimating  uric  acid, 
we  must  refer  to  special  works  on  the  subject,  and  especially  to  IIuppert- 
Keubauek.' 

Xanthin  Bodies  (Alloxurio  I^ases).  The  alloxuric  bases  (purin  bases) 
found  in  human  urine  are  xanthin,  guanin^  hypoxanthin,  adenin,  para- 
a'authin,  heteroxa)ithin,  episarkin,  epigiiani7i,  l-methylxa7itJiin,  and  carnin. 
The  occurrence  of  gnanin  and  carnin  (Pouchet)  is,  according  to  Kruger 
and  Salomon,'  not  positively  shown.  The  quantity  of  these  bodies  in  the 
urine  is  extremely  small  and  variable  in  different  individuals.  Flatow 
and  Reitzensteix  *  found  15.0-45.1  milligrammes  in  urine  voided  during 
twenty-four  hours.  The  quantity  of  alloxuric  bases  in  the  urine  is  increased 
regularly  after  feeding  with  nucleus  nucleins  and  after  free  destruction  of 
leucocytes.  The  quantity  is  especially  increased  in  leucaemia.  AVe  have  a 
number  of  observations  on  the  elimination  of  these  bodies  in  different  dis- 
eases, but  they  are  hardly  trustworthy,  on  account  of  the  inaccuracy  of  the 
methods  used  in  the  determinations.  It  must  also  be  remarked  that  the  three 
alloxuric  bases,  heteroxanthin,  paraxanthin,  and   1-methylxanthin,   which 


1  Folin,  Zeitschr.   f.  pbysiol.  Cheiu.,  Bd.  24;  Hitter,  ibid.,  Bd.  21. 
"  Iliini-Analyse  10.  Aull.,  1898. 

2  Zeitschr.  f.  physiol.  Cliem.,  Bd.  24  ;  Poucbet,  "  Contributions  a  la  connaissauce  des 
maliires  e.vtiactives  de  I'urine."  TbJ^se  Paris,  1880.  Cited  from  lluppert-Xeubauer, 
S.  333  and  335. 

*  Deutscb.  med.  Wocbeuscbr.,  1897. 


436  URINE. 

form  the  chief  mass  of  the  alloxuric  bases  of  the  urine,  are  derived,  accord- 
ing to  the  investigations  of  Albanese,  Boi^dzynski  and  Gottlieb, 
E.  Fischer,  M.  Kruger  and  Gr.  Salomon,'  from  the  theobromin,  caliein, 
and  theophyllin  bodies  occurring  in  our  food.  As  the  four  real  nuclein 
bases  and  carnin  have  been  treated  of  in  Chapters  V  and  XI,  it  only  remains 
to  describe  the  special  urinary  xanthin  bodies. 

Heteroxanthin,  CnHoN403  — -  7-monomethylxantliin,  was  first  detected  in  the  urine 
by  Salomon.^  It  is  identical  with  tlie  monomelhylxanthin  whicli  passes  into  the  urine 
after  feeding  with  theobromin  or  cafEeiu. 

Heteroxanthin  crystallizes  in  sbiuing  needles  and  dissolves  with  difficulty  in  cold  water 
(1592  parts  at  18°  C).  It  is  readily  soluble  in  ammonia  and  alkalies.  The  crystalline 
sodium  salt  is  insoluble  in  stiong  caustic  alkali  (33^)  and  dissolves  with  difficulty  in  water. 
The  chloride  crystallizes  beautifully,  is  relatively  insoluble,  and  is  readily  decomposed  into 
the  free  base  and  hydrochloric  acid  by  water.  Heteroxanthin  is  precipitated  by  copper 
sulphate  and  bisulphite,  mercuric  chloride,  basic  lead  acetate  and  ammonia,  and  by  silver 
nitrate.  The  silver  compound  dissolves  rather  easily  in  dilute,  warm  nitric  acid  ;  it 
crystallizes  in  small  rhombic  plates  or  prisms,  often  grown  together,  forming  charac- 
teristic crosses.  Heteroxanthin  does  not  give  the  xanthin  reaction,  but  does  give 
"Weidel's  reaction  according  to  Fischek  (see  Chapter  V). 

l-Methylxanthin,  CoHeNiO^,  was  first  isolated  from  the  urine  and  studied  by  Krijger, 
and  then  by  Kr-dger  and  Salomon.'  It  is  diflicultly  soluble  in  cold  water,  but  readily 
soluble  in  ammonia  and  caustic  soda,  and  does  not  give  an  insoluble  sodium  combination. 
It  is  readily  soluble  in  dilute  acids.  The  chloride  is  decomposed  into  base  and  hydro- 
chloric acid  by  water.  1-methylxanthiu  gives  crystalline  double  salts  with  platinum  and 
gold.  It  is  not  precipitated  by  basic  lead  acetate,  and  when  pure  not  by  basic  lead 
acetate/ind  ammonia.  With  ammonia  and  silver  nitrate  it  gives  a  gelatinous  precipitate. 
The  silver  nitrate  compound  crystallized  from  nitric  acid  forms  rosettes  of  united 
needles.  With  the  xanthin  test  with  nitric  acid  it  gives  an  orange  coloration  on  the 
addition  of  caustic  soda.  It  gives  Weidel's  reaction  (according  to  Fischer)  beautifully. 

Paraxanthin,  CTHsNiOa  =  1.7-dimethylxanthin,  urotheobromin  (Thudichtjm),  was 
first  isolated  from  the  urine  by  Thudiciium  and  Salomon.*  It  crystallizes  beautifully 
in  six-sided  plates  or  in  needles.  The  sodium  combination  crystallizes  in  rectangular 
plates  or  prisms  and,  like  the  heteroxanthin  sodium  compound,  is  insoluble  in  33j^  caustic- 
soda  solution.  The  .sodium  compound  separates  in  a  crystalline  state  on  neutralizing  its 
solution  in  water.  The  chloride  is  readily  soluble  and  is  not  decomposed  by  water. 
The  chloroplatinate  crystallizes  very  beautifully.  Mercuric  chloride  precipitates  only 
when  added  to  excess  and  after  a  long  lime.  The  silver  nitrate  combination  separates 
as  white  silky  crystals  from  hot  nitric  acid  on  cooling.  It  gives  Weidel's  reaction,  but 
but  not  the  xanthin  test,  with  nitric  acid  and  alkali. 

Episarkin  is  the  name  given  by  Balke  to  a  new  xanthin  base  occurring  in  human 
urine.  The  same  body  has  been  observed  by  Salomon  ^  in  pigs'  and  dogs'  urine,  as  well 
as  in  urine  in  loucfeniia.  Balke  gives  C4H0N3O  as  the  probable  formula  for  episarkin. 
It  is  nearly  insoluble  in  cold  water,  dissolves  with  difficult}'- in  hot  water,  but  maybe 
obtained  therefrom  as  long  fine  needles.  Episarkin  does  not  give  the  xanthin  reaction 
with  nitric  acid  nor  Weidel's  reaction.  With  hydrochloric  acid  and  potassium  chlorate 
it  gives  a  while  residue  which  turns  violet  with  ammonia.  It  does  not  form  any  insol- 
uble sodium  compound.     The  silver  combination  is  difficultly  soluble  in  nitric  acid. 

'  Albane.se,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  35;  Bondzynski  and  Gottlieb,  ibid., 
Bd.  36,  and  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  28;  E.  Fischer,  ibid.,  Bd.  30,  S. 
2405;  Kruger  and  Salomon,  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

^  Du  Bois-Ileymond's  Arch.,  1885;  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  18;  Zeit- 
schr. f.  physiol.  Chem.,  Bd.  11. 

'  Kruger,  Du  Bois-Reymond's  Arch.,  1894 ;  Kriiger  and  Salomon,  Zeitschr.  f. 
physiol.  Chem.,Bd.  24. 

■•  Thudichiim,  "  Grundziige  d.  anal.  med.  kiln.  Chemie"  (Berlin,  1886);  Salomon, 
Du  Bois-Reymond's  Arch.,  1882,  and  Ber.  d.  deutscli.  chem.  Gesellsch.,  Bdd.  16  and  18. 

'  Balke,  "  Zur  Kenntniss  der  Xanthinkorper  "  (luaug.-Diss.,  Leipzig,  1893) ;  Salomon, 
Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 


QUANTITATIVE  ESTIMATION  OF  XANTUIN BODIES.  437 

Epiguanin.  CJlTNtO  —  7-methylguauin  (KnCoEn  iiiul  Salomon)  was  first  prepared 
from  the  urine  hy  K)u'oKU.'  It  is  cryslulliiie  and  difficultly  soluble  in  Lot  water  or 
ammonia.  It  crystallizes  from  a  hot  '6'^%  ctuistic-soda  solution  on  cooling  into  broad 
shining  crystals.  It  dissolves  readily  in  hydrochloric  or  sulpiiuric  acid.  It  gives  a 
characteristic  chloroplatinate  crystallizing  in  six-sided  prisms.  It  is  precipitated  neither 
by  basic  lead  acefftte  nor  by  basic  lead  acetate  and  ammonia.  Silver  nitrate  and  am- 
monia give  a  gelatinous  precipitate.  It  gives  the  .xanthin  test  with  nitric  acid  and  alkali. 
According  to  Fisciii'.u  it  acta  like  episarkin  with  Wkidki-'s  test. 

In  i)reparing  xanthin  bodies  from  the  urine,  it  is  supersaturated  with  ammonia  and 
precipitated  by  a  silver-nitrate  solution.  The  precipitate  is  tiien  decomposed  with  sul- 
phuretted hydrogen.  The  boiling-hot  filtrate  is  evaporated  to  dryness  and  the  dried 
residue  treated  with  Z%  sulphuric  acid.  The  xanthin  bodies  are  dissolved,  while  the 
uric  acid  remains  undissolved.  This  filtrate  is  saturated  with  ammonia  and  pr(;cipitated 
by  silver-nitrate  solution.  If  instead  of  precipitating  with  silver  solution  we  desire  to 
precijutale,  according  to  Krijgeu  and  Wulff,-*  with  copper  suboxide,  we  heat  the  urine 
to  boiling  and  immediately  add,  successively,  100  c.c.  of  a  50^  sodium-bisulphite 
solution  atul  100  c.c.  of  a  12^  copper-sulphate  solution  for  every  litre  of  urine.  The 
thoroughly  washed  precipitate  is  decomposed  with  hydrochloric  acid  and  sulphuretted 
hydrogen.  The  uric  acid  remains  in  great  part  on  the  filter.  If  you  have  a  mixture  of 
the  silver  combinations  of  the  bases  (see  above),  they  may  be  decomposed  by  hydro- 
chloric acid.  Further  details  in  regard  to  the  treatment  of  the  solution  of  the  hydro- 
chloric-acid combinations  may  be  found  in  Krugeu  and  S.vlomon.' 

Quantitative  Estimation  of  Alloxuric  Buses  according  to  Salkowski/ 
400  to  600  c.c.  of  the  urine  free  from  proteid  is  first  precipitated  by 
magnesia  mixture  and  then  by  a  'd<fo  silver-nitrate  solution  as  described  on 
page  434.  The  thorouglily  washed  silver  precipitate  is  decomposed  by 
sulphnretted  hydrogen  after  being  suspended  in  600-800  c.c.  water  with 
the  addition  of  a  few  drops  of  hydrochloric  acid.  It  is  heated  to  boiling 
and  filtered  hot,  and  finally  evaporated  to  dryness  on  the  water-bath.  The 
residue  is, extracted  witli  20-30  c.c.  hot  o'fc  sulphuric  acid  and  allowed  to 
stand  2-4  hours,  the  uric  acid  filtered  off,  washed,  the  filtrate  made  am- 
moniacal,  and  the  xanthin  bodies  precipitated  again  by  silver  nitrate,  tlie 
precipitate  collected  on  a  small,  chlorine-free  filter,  washed  thorouglily, 
dried,  carefully  incinerated,  the  ash  dissolved  in  nitric  acid,  and  titrated 
with  ammonium  sulphocyanide  according  to  Yolhard's  method.  The 
ammonium-sulphocyanide  soliition  should  contain  1.2-2.4  grms.  per  litre 
and  its  strength  be  determined  by  a  silver-nitrate  solution:  1  part  silver 
corresponds  to  0.277  grm.  nitrogen  of  alloxuric  bases  or  to  0.7381  grm. 
alloxuric  bases.  By  this  method  the  uric-acid  and  alloxuric  bases  can  be 
simultaneously  determined  in  the  same  portion  of  urine.' 

Malfatti*  determines  the  nitrogen  of  the  alloxuric  bases  in  the  filtrate  from  the 
separated  uric  acid  containing  liydrochloric  acid.  This  filtrate  is  evaporated  with 
nuignesia  until  all  ammonia  has  been  expelled  and  the  residue  used  for  the  Kjeldahl 
determination. 

The  nitrogen  of  the  alloxuric  bases  is  also  determined  as  the  difference  between  the 


•  Du  Bois-Reymond's  Arch.,  189-t  ;  Kriiger  and  Salomon,  Zeitschr.  f.  physiol.  Chem., 
Bdd.  24  and  2G. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 

*  Ibid.,  26. 

*  Pfliiger's  Arch.,  Bd.  69. 

'  In  regard  to  details  we  refer  the  reader  to  the  original  paper. 

•  Centralbl.  f.  innere  Med.,  1897. 


438  URINE. 

uric  acid  nitrogen  and  the  total  nitrogen  of  the  alloxuric  bodies  of  the  silver  precipitate 
(Camerer,  Arnstein  ').  Salkowski  lias  raised  the  objection  to  this  procedure  that  it 
is  not  possible  to  remove  all  the  ammonia  from  the  silver  precipitate  by  washing.  Ac- 
cording to  Arnstein,''  this  can  readily  be  done  by  boiling  the  precipitate  in  water 
and  some  magnesia,  and  under  these  circumstances  this  method  is  quite  serviceable. 
The  nitrogen  is  estimated  by  Kjeldahl's  method.  The  uric-acid  nitrogen  multiplied 
by  3  gives  the  quantity  of  uric  acid.  As  the  mixture  of  alloxuric  bases  in  the  iirine  is 
not  known,  the  quantity  of  nitrogen  of  the  alloxuric  bases  is  always  calculated  as  a 
certain  alloxuric  base,  for  example  xanthin  (Caivierer),  and  the  quantity  bo  found  used 
as  a  measure  for  the  alloxuric  bases.  Kruger  and  Wulpp's  method  has  been  shown 
by  the  researches  of  Huppert,  Salkowski,  Flatow,  and  Reitzenbtein  ^  not  to  yield 
sufficiently  accurate  results. 

Oxaluric  Acid,  C3H4N2O4  =  (CON2H3)CO.COOH.  This  acid,  whose  relation  to 
uric  acid  and  urea  has  been  spokeu  of  above,  occurs  only  as  traces  in  the  urine  as 
ammonium  salts.  This  salt  is  not  directly  precipitated  by  CaCla  and  NH3 ,  but  after 
boiling,  when  it  is  decomposed  into  urea  and  oxalate.  In  preparing  oxaluric  acid  from 
urine  the  latter  is  filtered  through  animal  charcoal.  The  oxalurate  retained  by  the 
charcoal  may  be  obtained  by  boiling  with  alcohol. 

POO  IT 
Oxalic  Acid,  0  JI^O^ ,  or   ■  ,  occurs  nnder  physiological  conditions 

in  very  small  amounts  in  the  urine,  about  0,02  grm.  in  24  hours  (FuR- 
BRiNGER'').  According  to  the  generally  accepted  view  it  exists  in  the 
urine  as  calcium  oxalate,  which  is  kept  in  solution  by  the  acid  phosphates 
present.  Calcium  oxalate  is  a  frequent  constituent  of  urinary  sediments, 
and  occurs  also  in  certain  urinary  calculi. 

The  origin  of  the  oxalic  acid  in  the  urine  is  not  well  known.  Oxalic 
acid  wlien  administered  is  eliminated,  at  least  in  part,  by  the  urine 
unchanged; '  and  as  many  vegetables  and  fruits,  such  as  cabbage,  spinach, 
asparagus,  sorrel,  apples,  grapes,  etc.,  contain  oxalic  acid,  it  is  possible  that 
a  part  of  the  oxalic  acid  of  the  urine  originates  directly  from  the  food. 
That  oxalic  acid  may  be  formed  in  the  animal  body  as  metabolic  products 
from  proteids  or  fats  follows  from  the  observations  of  Mills  and  Luthje,^ 
who  found  in  dogs  on  an  exclusively  meat  and  fat  diet,  as  also  in  starvation, 
that  oxalic  acid  was  eliminated  by  the  urine.  A  part  of  the  oxalic  acid 
may  also  be  due  to  a  greater  destruction  of  proteids  or,  as  found  by  Eeale 
and  BoEKi,  as  well  as  TEiiKAY,'  a  greater  quantity  of  oxalic  acid  eliminated 
with  diminished  oxygen  supply  and  increased  proteid  destruction.  Some 
claim  that  oxalic  acid  is  formed  by  an  incomplete  combustion  of  the  carbo- 


'  Camerer,  Zeitschr.  f.  Biologic,  Bdd.  20  and  28  ;  Arnstein,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  23. 

'  Salkow.ski,  1.  c. ;  Arnstein,  Ceutralbl.  f.  d.  med.  Wissensch.,  1898. 

nirilger  and  Wulff,  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  20;  Huppert,  ibid.,  Bd.  22; 
Salkowski,  Deutsch.  med.  Wochenschr.,  1897  ;  Flatow  and  Reitzenstein,  ibid.,  1897. 

*  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  18.  See  also  Dunlop,  Jouru.  Path,  and  Bacterid., 
Vol.  3. 

*  In  regard  to  the  behavior  of  oxalic  acid  in  the  animal  body  see  page  476. 
«  Mills,  Virchow's  Arch.,  Bd.  99;  Liithjc,  Zeitschr.  f.  klin.  Med.,  Bd.  35. 

'  Reale  and  Boeri,  Wien.  med.  Wochenschr.,  1895;  Terray,  Piluger's  Arch.,  Ed.  65. 


ALLANTOIN.  439 

iiydrates,  but  tliis  is  denied  by  Lutu.jk,  and  finally  the  oxalic  acid  of  the 
nrine  is  considered  us  an  oxidation  product  of  uric  acid.  Lommel  '  has 
found  for  three  days  witli  food  free  from  oxalic  acid  and  taking  eacli  day 
0.G71  grni.  oxalic  acid,  as  sodium  oxalate,  that  only  lOJiji^  of  the  acid 
was  regained  in  the  urine  and  faeces,  which  seems  to  show  that  the 
acid  is  consumed  in  the  animal  body.  When  an  increase  in  the  uric  aCid 
eliminated  was  obtained  by  feeding  with  thymus,  the  elimination  of  oxalic 
acid  was  simultaneously  increased.  Lommel  has  also  found  that  gelatin 
considerably  increases  the  elimination  of  oxalic  acid. 

An  increased  elimination  of  oxalic  acid  may  occur  in  diabetes  and 
icterus.  The  question  whether  it  occurs  as  an  independent  disease  {oxa- 
Inria,  oxalic-acid  diathesis)  has  not  been  positively  decided. 

The  properties  and  reactions  of  oxalic  acid  and  calcium  oxalate  are  well 
known.  Calcium  oxalate  as  a  constituent  of  urinary  sediments  will  be 
described  later. 

Detection  and  Quantitative  EHimation  of  Oxalic  Acid  in  Urine.  Th6 
presence  of  oxalic  acid  in  solution  in  urine  is  determined  according  to  the 
method  suggested  by  Neubauer,  who  treats  500-GOO  c.c.  of  the  urine  with 
CaCl,  solution,  makes  alkaline  with  ammonia  and  then 'faintly  acid  with 
acetic  acid.  After  24  hours  the  precipitate  is  collected  on  a  small  filter, 
washed  with  water,  treated  with  hydrochloric  acid  (which  leaves  the  uric 
acid  undissolved  on  the  filter),  and  washed  again  with  water.  The  filtrate, 
including  the  wash-water,  is  treated  with  an  excess  of  ammonia  and  allowed 
to  stand  24  hours.  Calcium  oxalate  separates  as  quadratic  octahedra.  The 
quantitative  estimation  is  performed  after  the  same  principle.  The  oxalate 
is  converted  into  quicklime  by  heat,  and  weighed  as  such, 

All     .  •  n  Ti  AT  A       .,^/NH.CH.NH.CO.NH, 

Allantoin  or  glyoxyldiuueid,  C^H.N^O,  or  C0<^ ,^„  ^^  *, 

occurs  in  the  urine  of  children  within  the  first  eight  days  after  birth,  and 
in  very  small  amounts  also  in  the  urine  of  adults  (Gusserow,  Ziegler  and 
Hermanx).  It  is  found  in  rather  abundant  quantities  in  the  urine  of 
pregnant  women  ((Iusserow).  Allantoin  has  also  been  found  in  the  urine 
of  sucking  calves  (Wuiiler),  and  sometimes  in  the  urine  of  other  animals 
(Meissxer).  It  is  also  found  in  the  amniotic  fluid  and,  as  first  shown  by 
Yaui^uelix  and  Lassaioxe,'  in  the  allantoic  fluid  of  the  cow  (hence  the 
name).  Allantoin  is  formed,  as  above  stated,  by  the  oxidation  of  uric  acid. 
The  increased  elimination  of  allantoin  which  Salkowski  observed  in  dogs 

•  Conimuiiicatlou  of  Fr.  Voit,  Sitzungsber.  d.  Gesellscli.  f.  Morph.  u.  Ph3siol.  ia 
Mlincben.  1899. 

'  Ziegler  and  Hermann,  see  Gusserow,  Arch.  f.  Gyniikol,  Bd.  3— both  cited  from 
Huppert-Neubauer,  Haru-Aualyse,  10.  Aufl.,  S.  377;  Wohler,  Annal.  d.  Chem.  u. 
Phnrm.,  Bd.  70  ;  Meissner,  Zeitscbr.  f.  rat.  Med.  (3),  Bd.  31;  Lassaigne,  Annal.  de  Chim. 
et  Pbys.,  Tome  17. 


440  URINE. 

after  the  administration  of  uric  acid  shows  that  the  formation  of  allantoin 
from  uric  acid  in  the  organism  is  not  improbable.  Boeissow  has  observed 
an  abundant  elimination  of  allantoin  in  dogs  after  poisoning  with  diamid, 
and  Th.  CoHisr  has  observed  an  abundant  elimination  of  allantoin  after 
thymus  feeding.  Salkowski^  has  observed  the  same  on  feeding  with 
pancreas.     Allantoin  has  also  been  found  in  the  plant  kingdom. 

Allantoin  is  a  colorless  substance  often  crystallizing  in  prisms,  difficultly 
soluble  in  cold  water,  easily  soluble  in  boiling  water  and  also  in  warm 
alcohol,  but  not  soluble  in  cold  alcohol  or  ether.  It  combines  with  acids, 
forming  salts.  A  watery  allantoin  solution  gives  no  precipitate  with  silver 
nitrate  alone,  but  by  the  careful  addition  of  ammonia  a  white  flocculent 
precipitate  is  formed,  C^H^AglST^Og ,  which  is  soluble  in  an  excess  of 
ammonia  and  which  consists  after  a  certain  time  of  very  small,  transparent 
microscopic  globules.  The  dried  precipitate  contains  40.75^  silver.  A 
watery  allantoin  solution  is  precipitated  by  mercuric  nitrate.  On  continu- 
ous boiling  allantoin  reduces  Fehlikg's  solution.  It  gives  Schiff's  fnr- 
f  urol  reaction  less  rapidly  and  less  intensely  than  urea.  Allantoin  does  not 
give  the  murexid  test. 

All^mtoin  is  most  easily  prepared  by  the  oxidation  of  uric  acid  with  lead 
peroxide.  In  preparing  allantoin  from  calves'  urine,  concentrate  the  urine 
on  the  water-bath  to  a  syrup  and  allow  it  to  stand  in  the  cold  for  several 
days.  The  crystals  which  are  separated  from  the  precipitate  by  washing 
are  dissolved  in  boiling  water  with  the  addition  of  some  animal  charcoal, 
and  filtered  while  hot;  then  acidify  the  filtrate  faintly  with  hydrochloric  acid 
(so  as  to  keep  the  phosphates  in  solution)  and  allow  it  to  crystallize. 
Allantoin  is  detected  in  human  urine  by  the  method  first  suggested  by 
Meissxer.  It  consists  chiefly  of  the  following  points:  Precipitate  the 
urine  with  baryta-water,  filter,  remove  the  baryta  with  sulphuric  acid,  filter 
again,  precipitate  the  allantoin  with  HgOl^  in  alkaline  solution,  decompose 
the  precipitate  with  sulphuretted  hydrogen,  concentrate  strongly,  purify 
the  crystals  which  separate  by  recrystallization,  and  lastly  prepare  the  silver 
combination. 

Hippuric  Acid,  or  benzoyl-amido  acetic  acid,  CgH^lSrOj  or  CgH^.CO. 
NH. OH,. coon.  This  acid  decomposes  into  benzoic  acid  and  glycocoll  on 
boiling  the  urine  with  mineral  acids  or  alkalies,  and  also  by  joutrefaction. 
The  reverse  of  this  occurs  if  these  two  components  are  heated  in  a  sealed 
tube  according  to  the  following  equation:  OJI.COOII  +  NII,.CII,.COOH 
=  CJI,.CO.NII.CII,.COOII  +  11,0.  This  acid  may  be  synthetically  pre- 
pared from  benzamid  and  monochlor-acetic  acid,  CJI^.CO.NH,  +  CIIjCl. 
COOII  =  C,H,.CO.NH.CII,.COOn  +  IICl,  and  in  various  other  ways. 

Ilippnric  acid  occurs  in  large  amounts  in  the  urine  of  herblvora,  but 
only  in  small  quantities  in  that  of  carnivora.     The  quantity  of  hipiiuric 

'  Salkowski,  Ber.  d.  deutsch.  chcm.  Gcsellsch.,  Bd.  9  ;  Borissow.Zeitscliv.  f.  pliysiol. 
Chem.,  Bd.  19;  Cohn,  ibid.,  25  ;  Salkowski,  Ccntralbl.  f.  d.  med.  Wissensch.,  1898. 


IllPPUIilC  ACID.  441 

acid  eliminated  in  human  urine  on  a  mixed  diet  is  usually  less  than  1  grm. 
per  day;  as  an  average  it  is  0.7  grm.  After  eating  freely  of  vegetables 
and  fruit,  especially  such  fruit  as  plums,  the  quantity  may  be  more  than 
2  grms.  Ilijipuric  acid  is  also  found  in  the  perspiration,  blood,  suprarenal 
capsule  of  oxen,  and  in  ichthyosis  scales.  Nothing  is  positively  known  in 
regard  to  the  quantity  of  hippuric  acid  in  the  urine  in  disease. 

The  Formation  of  Hippuric  Acid  in  the  Organism.  Benzoic  acid  and 
also  the  substituted  benzoic  acids  are  converted  into  hippuric  acid  and  sub- 
stituted hippuric  acids  within  the  body.  Moreover,  tliose  bodies  are  trans- 
formed into  hippuric  acid  which  by  oxidation  (toluol,  cinnamic  acid, 
hvdrocinnamic  acid)  or  by  reduction  (quinic  acid)  are  converted  into  ben- 
zoic acid.  The  question  of  the  origin  o^  hippuric  acid  is  therefore  connected 
with  the  question  of  the  origin  of  bnnzoic  acid ;  for  the  formation  of  the 
second  component,  glycocoll,  frorr.  the  protein  substances  in  the  body  is 
unquestionable. 

Hippuric  acid  is  found  in  the  urine  of  starving  dogs  (Salkowski),  also 
in  dog's  urine  after  a  diet  consisting  entirely  of  meat  (Meissxer  and 
SnEPARD,  SALKO^vsKI,  and  others ').  It  is  evident  that  the  benzoic  acid 
originates  in  these  cases  from  the  proteids,  and  it  is  generally  admitted  that 
it  is  produced  by  the  putrefaction  of  proteids  in  the  intestine.  Among  the 
products  of  the  putrefaction  of  proteid  outside  of  the  body  Salkowski  has 
found  phenylpropiouic  acid,  C,II,.  CH„.CH,.COOH,  which  is  oxidized  in 
the  organism  to  benzoic  acid  and  eliminated  as  hippuric  acid  after  combin- 
ing with  glycocoll.  Phenylpropiouic  acid  seems  to  be  formed  from  the 
amidophenylpropionic  acid,  which  is  derived  only  from  the  plant  proteids. 
The  supposition  that  the  pheuylpropionic  acid  is  produced  from  tyrosin  by 
putrefaction  in  the  intestine  has  not  been  substantiated  by  the  researches  of 
Baumaxx,  Schottex,  and  13aas.^  The  importance  of  putrefaction  in  the 
intestine  in  producing  hipi)nric  acid  is  evident  from  the  fact  that  after 
thoroughly  disinfecting  the  intestine  of  dogs  with  calomel  the  hippuric  acid 
disappears  from  the  urine  (Baumaxx  ^). 

The  large  quantity  of  hippuric  acid  present  in  the  urine  of  herbivora  is 
partly  explained  by  the  specially  active  processes  of  putrefaction  going  on 
in  the  intestine  of  herbivora,  but  is  especially  due  to  the  large  quantity  of 
substances  forming  benzoic  acid  in  the  plant-food.  According  to  Gotze 
and  Pfeiffer*  the  pentoses  stand  in  close  connection  with  the  elimination 


'  Salkowski,  Ber.  d.  deutsch.  cbeni.  Gesellsch.,  Bd.  11  ;  Meissner  and  Shepard,  Un- 
tersucb.  iibor  das  Eutsteheu  der  Hippursilure  im  tbieriscben  Orgauismus.  Hannover, 
1866. 

'  E.  and  H.  Salkowski,  Ber.  d.  deutscb.  cbem.  Gesellscb.,  Bd.  12;  Baumann,  Zeit- 
schr.  f.  pbysiol.  Cbem.,  Bd.  7 ;  Scholten,  ibid.,  Bd.  8  ;  Baas,  ibid.,  Bd.  11. 

»76jV?.,'Bd.  10,  S.  131. 

*  See  Muly's  Jabresber.,  Bd.  26. 


442  URINE. 

of  hippuric  acid  in  sheep.  There  is  hardly  any  doubt  that  the  hipparw 
acid  in  hamau  urine  after  a  mixed  diet,  and  especially  after  a  diet  of 
vegetables  and  fruits,  originates  in  part  from  the  aromatic  substances  form- 
ing benzoic  acid,  namely,  qninic  acid. 

The  kidneys  may  be  considered  in  dogs  as  special  organs  for  the 
synthesis  of  hippuric  acid  (Schmiedeberg  and  Bunge').  In  other 
animals,  as  in  rabbits,  the  formation  of  hippuric  acid  seems  to  take  place  in 
other  organs,  such  as  the  liver  and  muscles.  The  synthesis  of  hippuric  acid 
is  therefore  not  exclusively  limited  to  any  special  organ,  though  perhaps  in 
some  species  of  animals  it  may  be  more  abundant  in  one  organ  than  in 
another. 

Properties  and  reactions  of  Hippuric  Acid.  This  acid  crystallizes  in 
semi-transparent,  long,  four-sided,  milk-white,  rhombic  prisms  or  columns, 
or  in  needles  by  rapid  crystallization.  They  dissolve  in  600  parts  cold 
•water,  but  more  easily  in  hot  water.  They  are  easily  soluble  in  alcohol, 
but  with  difficulty  in  ether.  They  are  more  easily  soluble  (about  12  times) 
in  acetic  ether  than  in  ethyl  ether.  Petroleum  ether  does  not  dissolve 
them. 

On/lieating  hippuric  acid  it  first  melts  at  187.5°  C.  to  an  oily  liquid 
which  crystallizes  on  cooling.  By  continuing  the  heat  it  decomposes,  pro- 
ducing a  red  mass  and  a  sublimate  of  benzoic  acid,  with  the  generation, 
first,  of  a  peculiar  pleasant  odor  of  hay,  and  then  an  odor  of  hydrocyanic 
acid.  Hippuric  acid  is  easily  differentiated  from  benzoic  acid  by  this 
behavior,  also  by  its  crystalline  form  and  its  insolubility  in  petroleum  ether. 
Hippuric  acid  and  benzoic  acid  both  give  Lucke's  reaction,  namely,  they 
generate  an  intense  odor  of  nitrobenzol  when  evaporated  with  nitric  acid  to 
dryness  and  when  the  residue  is  heated  in  a  glass  tube  with  sand.  Hippuric 
acid  forms  crystallizable  salts,  in  most  cases,  with  bases.  The  combinations 
with  alkalies  and  alkaline  earths  are  soluble  in  water  and  alcohol.  The 
silver,  copper,  and  lead  salts  are  soluble  with  difficulty  in  water;  the  iron- 
oxide  salt  is  insoluble. 

Hippuric  acid  is  best  prepared  from  the  fresh  urine  of  a  horse  or  cow. 
The  urine  is  boiled  a  few  minutes  with  an  excess  of  milk  of  lime.  The 
liquid  is  filtered  while  hot,  concentrated  and  then  cooled,  and  the  hippuric 
acid  precipitated  by  the  addition  of  an  excess  of  hydrochloric  acid.  The 
crystals  are  pressed,  dissolved  in  milk  of  lime  by  boiling,  and  treated  as 
above;  the  hippuric  acid  is  precipitated  again  from  the  concentrated  filtrate 
by  hydrochloric  acid.  The  crystals  are  purified  by  recrystallization  and 
decolorized,  when  necessary,  by  animal  charcoal. 

The  (juantitative  estimation  of  hippuric  acid  in  the  urine  may  be  per- 
formed by  the  following  method  (Bunge  and  Schmiedeberg''):  The  urine 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  6  ;  also  Ar.  IIoffmanQ,  ihid.,  Bd.  7,  aud  Kochs, 
PflUger's  Arch.,  Bd.  20. 

'•'  Arch.  f.  exp.  Path.  ii.  Pharm.,  Bd.  6. 


ETHEREAL   SULPnOIilC  ACIDS.  443 

is  first  made  faintly  alkaline  with  soda,  evaporated  nearly  to  dryness,  and 
the  residue  thorougiily  extracted  with  strong  alcohol.  After  the  evapora- 
tion of  the  alcohol  dissolve  in  water,  acidify  with  sulphuric  acid,  and 
completely  extract  by  agitating  (at  least  five  times)  witii  fresh  portions  of 
acetic  ether.  The  acetic  ether  is  then  repeatedly  washed  with  water,  which 
is  removed  by  means  of  u  separatory  funnel,  then  evaporated  at  a  medium 
temperature,  and  the  dry  residue  treated  repeatedly  with  petroleum  ether, 
which  dissolves  the  benzoic  acid,  oxyacids,  fat,  and  phenol,  wiiile  the 
hippuric  acid  remains  undissolved.  Tliis  residue  is  now  dissolved  in  a  little 
warm  water  and  evaporated  at  5U-G0°  C.  to  crystallization.  The  crystals 
are  collected  on  a  small  weighed  filter.  The  mother-liquor  is  repeatedly 
shaken  with  acetic  ether.  This  last  is  removed  and  evaporated ;  the  residue 
is  added  to  the  above  crystals  on  the  filter,  dried  and  weighed. 

Phenaceturic  Acid,  Colli  1NO3  =  CIIi.ClIj.CO.NII.CHi.COOH.  This  acid,  which 
is  producL-d  iu  the  animal  body  by  a  grouping  of  the  phenylacelic  acid,  Calls. CH^.COOH. 
formed  by  the  putrefaction  of  the  proteids  with  glycocoil,  has  been  prepared  from 
horse's  urine  by  Salkowski,'  but  it  probably  also  occurs  in  human  urine. 

Benzoic  Acid,  C7H„0j  or  CMIs.COOH,  is  found  in  rabbit's  urine  and  sometimes, 
though  in  small  amounts,  in  dog's  urine  (WEYLand  v.  Ankkp).  According  to  .Jaaus- 
VELO  and  Stokvis  and  to  Kuonixkeu  it  is  also  found  in  human  urine  in  diseases  of 
the  kidne3's.  Tlie  occurrence  of  benzoic  acid  in  the  urine  seems  to  be  due  to  a  fer- 
mentative decomposition  of  hiiipuric  acid.  Such  a  decomposition  may  very  easily 
occur  in  an  alkaline  urine  or  one  containing  proteid  (Van  de  Velde  and  Stokvis). 
In  certain  animals — pigs  and  dogs — the  kidneys,  according  to  Schmikueueug  and 
Minkowski,^  contain  a  special  enzyme,  Sciimiedeberg's  hiatozym,  which  splits  the 
hippuric  acid  with  the  .separation  of  benzoic  acid. 

Ethereal  Sulphuric  Acids.  In  the  putrefaction  of  proteids  in  the  intes- 
tine, phenols,  whose  mother-substance  is  considered  to  be  tyrosin,  and 
indol  and  skatol  are  produced.  These  phenols  directly,  and  the  two  last- 
named  bodies  after  they  have  been  oxidized  into  indoxyl  and  skatoxyl, 
pass  into  the  nrine  as  ethereal  sulphuric  acids  after  uniting  with  sulphuric 
acid.  The  most  important  of  these  ethereal  acids  are  phenol-  and  crcsol- 
sulphiiric  acid — which  were  formerly  also  called  phenol-forming  substance 
— indoxyl-  and  sl-atoxyl-sulphuric  acid.  To  this  group  belong  also  the 
pyrocatechin-sidphuric  acid,  which  occurs  only  in  very  small  amounts  in 
human  urine,  and  hi/drochinoti-sidpJiuric  acid,  which  appears  in  the  urine 
after  poisoning  with  jihenol,  and  under  physiological  conditions  perhaps 
other  ethereal  acids  occur  which  have  not  been  isolated.  The  ethereal 
sulphuric  acids  of  the  urine  were  discovered  and  specially  studied  by 
Baumann.'  The  quantity  of  these  acids  in  human  urine  is  small,  while 
horse's  urine  contains  larger  quantities.  According  to  the  determinations 
of  V.  n.  Veldex  the  quantity  of  ethereal  sulphuric  acid  in  human  urine  in 
the  24  hours  varies  between  0.094  and  0.620  grms.     The  relationship  of 

>  Zeitschr   f.  physiol.  Chem.,  Bd.  9. 

*  Weyl  and  V.  Anrep,  Zeitschr.  f.  physiol.  Chem.,  Bd.  4;  Jaarsveld  and  Stokvis, 
Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  10;  Krouecker,  ibid.,  Bd.  16  ;  Van  der  Velde  and 
Stokvis,  ibid.,  Bd.  17;  Schmiedeberg,  ibid.,  Bd.  14,  S.  379;  Minkowski,  ibid.,  Bd.  17. 

»  Pfluger's  Arch.,  Bdd.  12  and  13. 


444  .         URINE. 

the  snlphate-sulphuric  acid  A  to  the  conjugated  sulphuric  acid  B  in  health 
is  on  an  average  as  10  :  1.  It  undergoes  such  great  variation,  as  found  by 
Baumaxx  and  Hertee  '  and  after  them  by  many  other  investigators,  that 
it  is  hardly  possible  to  consider  the  average  figures  as  normal.  After  taking 
phenol  and  certain  other  aromatic  substances,  as  well  as  when  putrefaction 
■within  the  organism  is  general,  the  elimination  of  ethereal  sulphuric  acid  is 
greatly  increased.  On  the  contrary  it  is  diminished  when  the  putrefaction 
in  the  intestine  is  reduced  or  prevented.  For  this  reason  it  may  be  greatly 
diminished  by  carbohydrates  and  exclusive  milk  diet.''  The  intestinal 
putrefaction  and  the  elimination  of  ethereal  sulphuric  acid  has  also  been 
diminished  in  certain  cases  by  certain  therapeutic  agents  which  have  an 
antiseptic  action;  still  the  statements  are  not  unanimous.' 

Great  importance  has  been  given  to  the  relationship  between  the  total 
sulphuric  acid  and  the  conjugated  sulphuric  acid,  or  between  the  conjugated 
sulphuric  acid  and  the  sulphate-sulphuric  acid,  in  the  study  of  the  intensity 
of  the  putrefaction  in  the  intestine  under  different  conditions.  Several 
investigators,  F.  Mullee,  Salkowski,  and  y.  JSToorden, '  consider  cor- 
rectly that  this  relationship  is  only  of  secondary  value,  and  that  it  is  more 
correct  to  consider  the  absolute  value.  It  must  be  remarked  that  the  abso- 
lute values  for  the  conjugated  sulphuric  acid  also  undergo  great  variation, 
so  that  it  is  at  present  impossible  to  give  the  upper  or  lower  limit  for  the 
normal  value. 

Phenol-  and  p-Cresol-sulphuric  Acid,  CJI^.O.SO^.OH  and  C,H,.O.SO,. 
OH.  These  acids  are  found  as  alkali  salts  in  human  urine,  in  which  also 
orthocresol  has  been  detected.  The  quantity  of  cresol-sulphuric  acid  is 
considerably  greater  than  phenol-sulphuric  acid.  In  the  quantitative  esti- 
mation the  phenols  set  free  from  the  two  ethereal  acids  are  determined 
together  as  tribromphenol.  The  quantity  of  phenols  which  are  separated 
from  the  ethereal-sulphuric  acids  of  the  urine  amounts  to  17-51  milli- 
grammes in  the  24  hours  (Ml'Nk).  The  methods  for  the  quantitative  esti- 
mation used  heretofore  give,  according  to  Eumpf,  as  well  as  Kossler  and 
Penny,'  such  inaccurate  results  that  new  determinations  are  very  desirable. 
After  a  vegetable  diet  the  quantity  of  these  ethereal-sulphuric  acids  is 

'  v.  d.  Veldcn,  Virchow's  Arcb.,  Bd.  70;  Herter,  Zeitscbr.  f.  pbysiol.  Cbem,,  Bd.  1. 

*  See  Hirscbler,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  10  ;  Biernacki,  Deutscb.  Arch.  f. 
kliri.  j\Ied.,  Bd.  49  ;  Bovigbi,  Zeitsclir.  f.  physiol.  Chcm.,  Bd.  16  ;  Wiuternitz,  ibid.,  and 
Scbmitz,  ibid.,  Bdd.  17  and  19. 

"  See  Biiumann  and  Morax,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  10;  Steiff,  Zeitscbr.  f. 
klin  Med  ,  Bd.  16;  liovigbi,  1.  c. ;  Stern,  Zeitscbr.  f.  Hygiene,  Bd.  12;  and  Bartoscbe- 
witscb,  Zeitscbr.  f.  physiol.  Cbem.,  Bd.  17  ;   Mosse,  ibid.,  Bd.  23. 

*Muller,  Zeitscbr.  f.  klin.  Med.,  Bd.  12;  v.  Noorden,  ibid.,  Bd.  17;  Salkowski. 
Zeitsclir.  f.  pbysiol.  Cbem.,  Bd.  12. 

5  Munk,  PflQger's  Arch.,  Bd.  12  ;  Rumpf,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  16 ; 
Kossler  and  Penny,  ibid.,  Bd.  17. 


PHENOL  AND  P-CRESOL  SULPnUIilC  ACID.  445 

greater  than  after  a  mixetl  diet.  After  taking  carbolic  ucid,  which  is  in 
great  part  converted  by  synthesis  within  the  organism  into  plienol-ethereal- 
sulphuric  acid,  besides  also  j)yrocatechin-  and  liydrocliinon-siilphuric  acid,' 
and  also  when  the  amount  of  sulphuric  acid  is  not  suflicient  to  combine 
with  the  phenol,  forming  phenyl-glycuronic  acid,'  the  quantity  of  phenols 
and  ethereal-sulphuric  acids  in  the  urine  is  considerably  increased  at  the 
expense  of  the  sulphate-sulphuric  acid. 

An  increased  elimination  of  phenol-sulphnric  acids  occurs  in  active 
putrefaction  in  the  intestine  with  stoppage  of  the  contents  of  the  intestine, 
as  in  ileus,  diffused  peritonitis  with  atony  of  the  intestine,  or  tuberculoos 
enteritis,  but  not  in  simple  obstruction.  The  elimination  is  also  increased 
by  the  absorption  of  the  products  of  putrefaction  from  purulent  wounds  or 
abscesses.  An  increased  elimination  of  phenol  has  been  observed  in  a  few 
other  cases  of  diseased  conditions  of  the  body.' 

The  alkali  salts  of  phenol-  and  cresol-sulphuric  acids  crystallize  in  white 
plates,  similar  to  mother-of-pearl,  which  are  rather  freely  soluble  in  water. 
They  are  soluble  in  boiling  alcohol,  bnt  only  slightly  soluble  in  cold.  On 
boiling  with  dilute  mineral  acids  they  are  decomposed  into  sulphuric  acid 
and  the  corresponding  phenol. 

Phenol-sulphuric  acids  have  been  synthetically  prepared  by  Baum.vxx 
from  potassium  pyrosulphate  and  phenol-  or  p-cresol-potassium.  For  the 
method  of  their  preparation  from  urine,  whicii  is  rather  complicated,  the 
reader  is  referred  to  other  text-books.  The  quantitative  estimation  of  these 
ethereal-suliilmrio  acids  is  done  by  determining  tlie  amount  of  phenol  which 
may  be  separated  from  the  urine  as  tribromphenol.  In  this  determination, 
when  the  urine  is  not  specially  rich  in  phenol,  about  one  fourth  of  the 
total  quantity  for  a  day  is  used;  it  is  acidified  with  concentrated  hydro- 
chloric acid — 5  c.c.  for  every  100  c.c.  of  urine — and  distilled  until  a 
portion  of  the  distillate  does  not  give  the  slightest  reaction  for  phenols  with 
jMillox's  reagent  or  with  bromine-water.  The  distillate  is  now  carefully 
neutralized  with  soda  solution  (which  combines  with  the  benzoic  acid,  etc.) 
and  again  distilled  until  a  portion  of  the  distillate  is  free  from  phenol,  as 
shown  by  the  above-mentioned  reagents.  This  distillate  is  treated  with 
bromine-water  until  a  permanent  yellow  color  is  produced,  and  then  allowed 
to  stand  for  about  24  hours  in  the  cold;  the  crystalline  precipitate  is  then 
collected  on  a  small  weighed  filter,  washed  Avith  dilute  bromine-water,  dried 
over  sulphuric  acid  without  the  use  of  a  vacuum,  and  weighed  (100  parts 
tribromphenol  correspond  to  28.4  parts  phenol).  It  is  assumed  that  the 
paracresol  is  first  converted  by  the  bromine- water  into  tribromcresol 
bromine,  and  that  this  is  then  gradually  changed  into  tribromphenol  with 
the  discharge  of  carbon  dioxide.     As  shown  by  Rumpf  this  is  not  the  case, 

'  See  Baumann,  Pflilger's  Arch.,  Bdd.  12  and  13,  and  Baumann  and  Preusse,  Zeit- 
schr.  f.  physiol.  Chem.,  Bd.  3,  S.  156. 

'  Schmiedeberg,  Arcli.  f.  exp.  Path.  u.  Pharm.,  Bd.  14. 

*  See  G.  Hoppe-Seyler,  Zeitschr.  f.  physiol.  Chem.,  Bd.  12.  This  contains  also  all 
references  to  the  literature  on  this  subject.     Fedeli.  Moleschott's  Untersuch.,  Bd.  15. 


446  URINE. 

but  dibromcresol  is  chiefly  formed  instead.  This  method  is  therefore  not 
available  for  this  and  other  reasons.  Among  the  other  methods  which  have 
been  suggested,  the  following  seems  to  be  the  most  available. 

KossLER  and  Penny's  Method.  This  method  is  a  modification  of 
Messixger  and  Yortmann's  '  volumetric  process  for  estimating  phenols. 
The  principle  of  this  process  is  as  follows:  The  liquid  containing  phenol  is 

treated  with  —  caustic  soda  until  strongly  alkaline,  warmed  on  the  water- 
bath  in  a  flask  with  a  glass  stopper,  and  then  treated  with  an  excess  of 
iodine  solution,  the  quantity  being  exactly  measured.     Sodium  iodide  is 

first  formed  and  then  sodium  hypoiodite,  which  latter  forms  tri-iodophenol 
with  the  phenol  according  to  the  following  equation : 

C.H.OH  +  3NaI0  =  C,H,l3.0H  +  SNaOH. 

On  cooling  acidify  with  sulphuric  acid,  and  determine   by  titration  with 

^-  sodium  thiosulphate  solution  the  excess  of  iodine  not  used.     This  process 

is  also  available  for  the  estimation  of  paracresol.  Each  c.c.  of  the  iodine 
solation  used  is  equivalent  to  1.5670  grms.  phenol  or  1.8018  grms.  cresol. 
As  the  determination  does  not  give  any  idea  as  to  the  variable  proportions 
of  the  two  phenols,  the  quantity  of  iodine  used  must  be  calculated  as  one 
or  the  cither  of  the  two  phenols.  Salkowski  and  Neuberg  '  have  shown 
that  KossLER  and  Penny's  method  gives  too  high  results  for  the  phenols 
in  the  presence  of  glucose  because  products  are  formed  from  the  carbo- 
hydrate on  distillation  which  combine  with  the  iodine.  The  method  must 
in  these  cases  be  modified  as  Neubebg  suggests.  In  regard  to  greater 
details,  and  especially  to  precautions,  we  must  refer  the  reader  to  the 
original  article  of  KossLERand  Pexny  and  to  IIuppert-Xeubauer.' 

The  methods  for  the  separate  determination  of  the  conjugated  sulphuric 
acid  and  the  sulphate-sulphuric  acid  will  be  spoken  of  later  in  connection 
with  the  determination  of  the  sulphuric  acid  of  the  urine. 

Pyrocatechin-sulphuric  Acid  (and  Pyrocatechin).  This  acid  was  first  fouud  in 
horse's  urine  in  rather  large  quantities  by  Baumann.  It  occurs  in  human  urine  only  in 
the  T«ry  smallest  quantities,  and  perhaps  not  constantly,  but  it  occurs  abundantly  in 
the  urine  after  taking  phenol,  pyrocatechin,  or  protocatechuic  acid. 

With  an  exclusively  meat  diet  this  acid  does  not  occur  in  the  urine,  and  it  therefore 
must  originate  from  vegetable  food.  It  probably  originates  from  the  protocatechuic 
acid,  which,  according  to  Preusse,  passes  in  part  into  the  urine  as  pyrocatechin-sul- 
phuric acid.  This  acid  may  also  perhaps  depend  on  oxidation  of  phenol  within  the 
organism  (Baumann  and  Pkeusse*). 

Pyrocatechin,  or  o-Dioxybenzol,  C«H<(0H)5  ,  was  first  observed  in  the  urine  of  a 
child  (Ebstein  and  J.  Mtjllek).  The  reducing  body  alcapton,  first  found  by 
BoDEKER^  in  human  urine  and  which  was  con.sidered  for  a  long  time  as  identical  with 
pyrocatechin,  is  in  most  cases  probably  homogcntisic  acid  or  uroleucic  acid  (see  below). 

'  Kossler  and  Penny,  1.  c;  Vortmann,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  22. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  27. 

'  Ilarn-Analyse,  10.  Aufl. 

*  Baumann  and  Ilcrter,  Zeitschr.  f.  physiol.  Chem.,  Bd.  1  ;  Preusse,  z&td.,  Bd.  2; 
Baumann,  ihid.,  Bd.  3. 

'  Ebstein  and  Mailer,  Virchow's  Arch.,  Bd.  G2  ;  BiJdeker,  Zeitschr.  f.  rat.  Med.  (3)^ 
Bd.  7. 


INDOXYL  SULPIJURIC  ACID.  447 

Pyrocatechiii  crystallizes  iu  prisms  wliich  are  soluble  in  alcohol,  ether,  and  water. 
It  melts  at  102-104°  C.  and  siiblinu'S  in  shining  plates.  The  watery  solution  becomes 
green,  brown,  and  ultimately  black  in  liie  presence  of  alkali  and  the  oxygen  of  the  air. 
If  very  dilute  ferric  chloride  is  treated  wiili  tartaric  acid  and  then  made  alkaline  with 
umuu>nia,  and  tiiis  addetl  to  a  watery  solution  of  pyrocatechiii,  we  obtain  a  violet  or 
cherry -red  litiuid  which  becomes  green  on  saturating  with  acetic  acid.  Pyrocatechin  is 
precii)ilated  by  lead  acetate.  It  reduces  an  ammoniacal  silver  solution  at  the  ordinary 
temperature,  aud.reduces  alkaline  copi)eroxide  solutions  with  heat,  but  does  not  reduce 
bisnuith  oxide. 

A  urine  containing  pyrocatechin  if  exposed  to  the  air,  especially  •when  alkaline, 
quickly  becomes  dark  and  reduces  alkaline  copper  solutions  when  heated.  In  detecting 
pyrocatechin  in  tiic  urine  it  is  concentrated  when  necessary,  liitered,  boiled  witii  the 
addition  of  sulphuric  acid  to  remove  the  i)henols,  and  repeatedly  shaken  after  cooling 
with  ellier.  The  ether  is  distilled  from  the  several  ethereal  extracts,  the  residue  neu- 
tralized with  barium  carbonate  and  shaken  again  with  ether.  The  pyrocatechin  which 
remains  after  evaporating  the  ether  may  be  purified  by  recrystallizatiou  from  benzol. 

Hydrochinon,  or  p-Dioxybenzol,  Ciil\t(0\l)i ,  often  occurs  in  the  urine  after  the  use 
of  phenol  (Baumann  and  Pueusse).  The  dark  color  which  certain  urines,  so-called 
"  carbolic  urines,"  take  in  the  air  is  due  to  decomposition  products.  Hydrochinon  does 
not  occur  as  a  normal  constituent  of  urine,  but  after  the  administration  of  hydrochinon  ; 
according  to  Lewix  '  it  passes  into  the  urine  of  rabbits  as  ethereal-sulphuric  acid,  being 
a  decomposition  product  of  arbutin. 

Hydrochinon  forms  rhombic  crystals  which  are  readily  soluble  in  water,  alcohol, 
and  ether.  It  melts  at  1()9°  C.  Like  pyrocatechin,  it  easily  reduces  metallic  oxides. 
It  acts  like  pyrocatechin  with  alkalies,  but  is  not  precipitated  with  lead  acetate.  It  is 
oxidized  into  chinon  by  ferric  chloride  and  other  oxidizing  agents,  and  chinon  is 
detected  by  its  peculiar  odor.  Hydrochinon-sulphuric  acid  is  detected  in  the  urine  by 
the  same  methods  as  pyrocatechiu-sulphuric  acid. 

Indoxyl-sulphuric  acid,  C,U,NSO,  or  CJI,N.0.80,.0H,  also  called 
urixp:  ixdicax,  formerly  called  uroxanthix  (Heller),  occurs  as  alkali- 
salt  in  the  urine.  Tliis  acid  is  the  mother-substance  of  a  great  part  of  the 
indigo  of  the  urine.  The  quantity  of  indigo  which  can  be  separated  from 
the  urine  is  considered  as  a  measure  of  the  quantity  of  indoxyl-sulphuric 
acid  (and  indoxyl-glycuronic  acid)  contained  in  the  urine.  This  amount, 
according  to  Jaffe,'  for  man  is  5-20  milligrammes  per  24  hours.  Ilorse's 
urine  contains  about  25  times  as  much  indigo-forming  substance  as  human 
urine. 

Indoxyl-sulphuric  acid  is  derived,  as  above  mentioned  (page  443),  from 
indol,  which  is  first  oxidized  in  the  body  into  indoxyl  and  is  then  coupled 
with  sulphuric  acid.  After  subcutaneous  injection  of  indol  the  elimination 
of  indican  is  considerably  increased  (Jaffe,  I3al'MAXN"  and  Brieger).  It 
is  also  increased  by  the  introduction  of  orthonitrophenylpropiolic  acid  in 
the  organism  of  animals  (G.  IIoppe-Seyler').  Indol  is  formed  by  the 
putrefaction  of  proteids,  and  it  is  therefore  easy  to  understand  why  the 
quantity  of  indoxyl-sulphuric  acid  is  greater  with  a  meat  than  with  a 
vegetable  diet.  The  putrefaction  of  secretions  rich  in  proteid  in  the  intes- 
tine explains  also  the  occurrence  of  indican  in  the  urine  during  starvation. 
Gelatin,  on  the  contrary,  does  not  increase  the  elimination  of  indican.     An 

'  Vircliow's  Arch.,  Bd.  93. 
«  Pfliiger's  Arch.,  Bd.  3. 

"  Jaffe,  Centralbl.  f.  d.  med.  "Wissensch.,  1872  ;  Baumann  and  Brieger,  Zeilschr.  f. 
physiol.  Chem.,  Bd.  3  ;  G.  IIoppe-Seyler,  ibid.,  Bdd.  7  and  8. 


448  VBINE. 

abnormally  increased  elimination  of  indican  occura  in  such  diseases  as 
obstruct  tbe  small  intestine,  causing  an  increased  putrefaction,  thus  pro- 
ducing an  abundant  formation  of  indol.  Such  an  increased  elimination  of 
indican  occurs  on  tying  the  small  intestine  of  a  dog,  but  not  the  large 
intesbine  (Jaffe'). 

An  increased  elimination  of  indican  may  also  be  caused  by  the  putrefac- 
tion of  proteids  in  other  organs  and  tissues  of  the  body  besides  the  intestine. 
An  increased  elimination  of  indican  has  been  observed  in  many  diseases," 
and  in  these  cases  the  quantity  of  phenol  eliminated  is  generally  increased. 
A  urine  rich  in  phenol  is  not  always  rich  in  indican. 

The  potassium  salt  of  indoxyl-sulphuric  acid,  which  was  prepared  pure 
by  BaumanjST  and  Bkieger  from  the  urine  of  a  dog  fed  on  indol,  has  since 
been  prepared  synthetically  by  Baumann  and  Thesen,'  who  first  prepared 
indoxylalkali  by  fusing  phenylglycin-orthocarbonic  acid  with  alkali  and 
then  from  this  produced  the  indoxylsulphate  with  potassium  pyrosulphate. 
It  crystallizes  in  colorless,  shining  plates  or  leaves  which  are  easily  soluble  in 
water,  but  less  readily  in  alcohol.  It  is  split  by  mineral  acids  into  sulphuric 
acid  and  indoxyl.  The  latter  without  access  of  air  passes  into  a  red  com- 
pound, indoxyl-red,  but  in  the  presence  of  oxidizing  reagents  is  converted 
into  iidigo-blue:  3C,H,N0  +  20  =  C„H,„N,0,  +  2H,0.  The  detection 
of  indican  is  based  on  this  last  fact. 

For  the  rather  complicated  preparation  of  indoxyl-sulphuric  acid  as 
potassium  salt  from  urine  the  reader  is  referred  to  other  text-books.  For 
the  detection  of  indican  in  urine  in  ordinary  cases  the  following  method  of 
Jaffe,*  which  also  serves  as  an  approximate  test  for  the  quantity  of  indican, 
is  sufficient. 

Jaffe's  Indican  Test.  20  c.c.  of  urine  is  treated  in  a  test-tube  with 
2-3  c.c.  chloroform  and  mixed  with  an  equal  volume  of  concentrated 
hydrochloric  acid.  Immediately  after  a  concentrated  chloride-of-lime  solu- 
tion or  a  1^  potassium-permanganate  solution  is  added  drop  by  drop,  and 
after  each  drop  the  mixture  is  thoroughly  shaken.  The  chloroform  is 
gradually  colored  faintly  or  strongly  blue.  An  excess  of  oxidizing  reagent, 
especially  chloride  of  lime,  interferes  with  the  reaction  and  must  therefore 
be  avoided.  The  test  is  repeated  with  somewhat  varying  amounts  of 
oxidizing  material  until  a  point  is  found  at  which  the  maximum  coloration 
of  the  chloroform  takes  place.  From  the  intensity  of  the  color  the  quantity 
of  indigo  is  determined. 

Still  better,  especially  for  the  quantitative  estimation  of  the  quantity  of 


'  Virchow's  Arch.,  Bd.  70. 

"  See  Jaffe,  Pflliger's  Arch.,  Bd.  3  ;  Senator,  Centralbl,  f.  d.  med.  Wissensch.,  1877  ; 
G.  Hoppe-Seylcr,  Zcilschr.  f.  physiol.  Chem.,  Bd.  12  (contains  older  literature) ;  also 
Berl.  kliii.  Wochenschr.,  1892. 

3  Bauraann  with  Brieger,  Zeitschr.  f.  physiol.  Chem.,  Bd.  3;  with  Thesen,  i5id., 
Bd.  23. 

*  Jaffe,  Ptluger's  Arch.,  Bd.  3. 


SKATOXTL-aULPHURlC  ACID.  449 

indigo,  is  Obermeyer's'  method,  lie  nsea  fuming  hydrochloric  acid 
containing  2— i  parts  ferric  chloride  per  litre  to  decompose  the  indican. 
The  urine  is  first  precipitated  with  not  too  much  lead  acetate  (about 
\  volume  of  a  'lQ';i  lead-acetate  solution),  and  the  filtrate  shaken  for  1-2 
minutes  with  an  equal  volume  of  the  above  liydrochloric  acid.  The  indigo- 
blue  is  taken  up  by  ciiloroform  in  this  case  also. 

According  to  Kosin'  some  indigo-red  is  always  formed  besides  the 
indigo-blue  in  Jaffe's  indican  test.  Greater  quantities  of  indigo-red  are 
formed  wlien  the  decomposition  of  the  indican  takes  place  in  the  warmth 
(see  RosENBACii's  urine  test). 

Tiie  chloroform  solution  of  indigo  obtained  in  the  indican  test  may  be 
used  in  the  quantitative  colorimetric  determination  by  comparison  with  a 
solution  of  iudigo  in  chloroform  of  known  strength  (Krauss  and  Adrian). 
Wang  '  converts  the  indigo  into  indigo-sulphonic  acid  by  concentrated 
sulphuric  acid  and  titrates  with  potassium  permanganate.  Obermeyer* 
has  suggested  a  similar  method  for  estimating  the  indican  independent  of 
Wang.  It  differs  from  Wang's  method  by  removing,  before  titration, 
other  pigments  taken  up  by  the  chloroform  by  washing  with  45,^  alcohol.' 
In  a  later  paper '  Wang  recommends  the  same  treatment,  namely,  washing 
with  alcohol-ether. 

Indol  seems  also  to  pass  into  the  urine  as  a  glycuronic  acid,  indoxyl- 
ghjcuronic  acid  (Schmiedeberg).  Such  an  acid  has  been  found  in  the 
urine  of  animals  after  the  administration  of  the  sodium-salt  of  o-nitro- 
phenylpropiolic  acid  (G.  Hoppe-8eyler'). 

Skatoxyl-sulphuric  Acid,  C.Ii.NSO,  or  0,H,.X.O.SO,.OII.  The  potas- 
sium salt  of  this  acid  seems  to  occur  generally  in  human  urine  as  a 
chromogen,  which  yields  a  red  or  violet  coloring  matter  on  decomposing  with 
strong  acids,  and  an  oxidizing  reagent.  This  salt  has  been  prepared  by 
Otto  "  from  diabetic  human  urine.  Little  is  known  of  the  quantity  of  this 
skatol-cliromogen,  to  which  probably  also  the  skatoxyl-gly^curonic  acid  mast 
be  counted,  under  physiological  and  pathological  conditions. 

Skatoxyl-sulphuric  acid  originates  from  skatol  formed  by  putrefaction 
in  the  intestine,  which  is  coupled  with  sulphuric  acid  after  oxidation  into 
skatoxyL  That  skatol  introduced  into  the  body  passes  partly  as  an  ethereal- 
sulpliuric  acid  into  the  urine  has  been  shown  by  Brieger.  Indol  and 
skatol  act  differently,   at  least   in   dogs;    indol    producing   a  considerable 

'  Obermayer,  Wien.  klin.  Wochenscbr.,  1890. 
'  Virchow's  Arch.,  Bd.  123. 

'Krauss,  Zeitsrhr.  f.  physiol.  Chem.,  Bd.  18;  Adrian,  ibid.,  Bd.  19;  Wang,  ibid., 
Bd.  25. 

*  Wicn.  kliii.  Rundschau,  1898. 

'  See  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

*  Ibid.,  Bd.  27. 

'  Schmiedeberg.  Arch  f.  exp.  Path.  u.  Pharm.,Bd.   14;  G.   HoppeSeyler,   Zeitschr. 
f.  physiol.  Chem.,  Bdd.  7  and  8. 
«  PflUger's  Arch. ,  Bd.  33. 


450  URINE. 

amonnt  of  ethereal -sulphnric  acid,  while  skatol  gives  only  a  small  quantity 
(Mester').  Skatol  seems  partly  to  pass  into  the  urine  as  a  skatoxyl- 
glycuronic  acid. 

The  potassium-salt  of  skatoxyl-snlphuric  acid  is  crystalline;  it  dissolves 
in  water,  but  with  difficulty  in  alcohol.  A  watery  solution  becomes  deep 
violet  with  ferric  chloride,  and  red  with  concentrated  nitric  acid.  The  salt 
is  decomposed  by  concentrated  hydrochloric  acid  with  the  separation  of  a 
red  precipitate.  The  nature  of  this  red  coloring  matter  produced  by  the 
decomposition  of  skatoxyl-sulphuric  acid  is  not  well  known;  neither  is  the 
relationship  existing  between  this  and  other  red  coloring  matters  in  the 
urine  known.  On  distillation  with  zinc-dust  the  skatol-chromogen  yields 
skatol. 

Urines  containing  skatoxyl  are  colored  dark  red  to  violet  by  Jaffe's 
indican  test  even  on  the  addition  of  hydrochloric  acid ;  with  nitric  acid  they 
are  colored  cherry-red,  and  red  on  warming  with  ferric  chloride  and  hydro- 
chloric acid.  The  coloring  matter  which  yields  skatol  with  zinc-dust  may 
be  removed  from  the  urine  by  ether.  Urines  rich  in  skatoxyl  darken  when 
allowed  to  stand  in  the  air  from  the  surface  downward,  and  may  become 
reddish,/  violet,  or  nearly  black.  Kosin  '  is  of  the  opinion  that  no  skatol- 
chromogen  exists  in  human  urine,  and  that  the  observations  made  heretofore 
were  due  to  a  confusion  with  indigo-red  or  urorosein. 

Salkowski^  has  shown  that  the  occurrence  of  skatol- carbonic  acid,  CgHs.N.COOH, 
in  normal  urine  is  probable.  This  is  also  a  putrefaction  product.  When  introduced 
into  the  animal  body  this  acid  reappears  unchanged  in  the  urine.  With  hydrochloric 
acid  and  very  dilute  ferric-chloride  solution  it  gives  an  intense  violet  color  to  the  solu- 
tion. The  reaction  responds  with  a  watery  solution  containing  1  :  10000  of  skatol  car- 
bonic acid. 

Aromatic  Oxyacids.  In  the  putrefaction  of  proteids  in  the  intestine^ 
paraoxyjyhejiyl-acetic  acid,  C,H,(OH).CH,COOH,  and  paraoxyplienyl-fro- 
pionic  acid,  CJi,(OH).C,H,.COOH,  are  formed  from  tyrosin  as  inter- 
mediate step,  and  these  in  great  part  pass  unchanged  into  the  urine.  They 
were  first  detected  by  Baumann.*  The  quantity  of  these  acids  is  usually 
very  small.  They  are  increased  by  the  same  circumstances  as  the* phenols, 
especially  in  acute  phosphorus-poisoning,  in  which  the  increase  is  consider- 
able.    A  small  portion  of  these  oxyacids  is  combined  with  sulphnric  acid. 

Besides  these  two  oxyacids  which  regularly  occur  in  human  urine  we 
sometimes  have  other  oxyacids  in  urines.  To  these  belong  liomogentisic 
acid  and  uroleucic  acid,  which  form  the  specific  constitnents  of  the  urine 


'  Brieger,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  12,  and  Zeitschr.  f.  physiol.  Chem., 
Bd.  4,  S.  414  ;  Mesler,  ibid.,  Bd.  12, 

»  Virchow's  Arch.,  Bd.  123. 

2  Zeitschr.  f.  ])hysiol.  Chem.,  Bd.  9. 

••  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  12  and  13,  and  Zeitschr.  f.  physiol.  Chem., 
Bd.  4. 


IIOMOGENTISTIC  ACID.  451 

in  most  cases  of  alcaptonuria,  oxymandelic  acid,  found  by  Schultzen  and 
KiKSS  in  urine  in  acute  atrophy  of  the  liver,  oxyJii/drojmracumaric  acid, 
found  by  Blkndkumanx  in  the  urine  on  feeding  ral)bits  witli  tyrosiu,  gallic 
acid,  which,  according  to  Baumann,'  sometimes  appears  in  horse's  urine, 
and  l-ynnrenic  acid  (oxycliinolincarbonic  acid),  which  up  to  the  present  time 
has  been  found  only  iu  dog's  urine.  Tiie  first  two  of  the  above-mentioned 
oxyacids,  and  also  homogentisic  and  uroleucic  acids,  will  be  treated  of  here. 
Paraoxyphenylacetic  acid  and  p-oxyphenylpropionic  acid  are  crystalline 
and  are  both  soluble  in  water  and  in  ether.  Tiie  first  melts  at  148°  C,  and 
the  other  at  125°  C.  Both  give  a  beautiful  red  coloration  on  being  warmed 
Avith  Millon's  reagent. 

To  detect  the  presence  of  these  oxyacids  proceed  in  the  following  way  (Bacmann)  : 
Warm  the  uriue  for  a  while  on  the  wuter-bath  with  hydrochloric  acid,  in  order  to  drive 
off  the  volatile  phenols.  After  cooling  shake  three  times  with  ether,  and  tlien  shake  the 
ethereal  extracts  with  dilute  soda  solution,  wliich  dissolves  the  oxyacids,  while  the  resi- 
due of  the  phenols  soluble  iu  ether  remains.  The  alkaline  solution  of  the  oxyacids  is 
now  faintly  aciditied  with  sulphuric  acid,  shaken  ag;iin  with  ether,  the  ether  removed 
and  allowed  to  evaporate,  the  residue  dissolved  in  a  little  water,  and  the  solution  tested 
with  SIillon's  reagent.  The  two  oxyacids  are  best  differentiated  by  their  different 
melting-points.  The  reader  is  referred  to  other  works  for  the  method  of  isolating  and 
separating  these  two  oxyacids. 

Homogentisic  acid,  CJI,0,  or  C.H,(OH),.CH,.COOII.  This  acid  was 
detected  by  Wolkoav  and  Baumann.  They  isolated  it  from  the  urine  in 
a  case  of  alcaptonuria  (see  below)  and  showed  that  the  characteristics  of 
so-called  alcaptonuric  urine  in  this  case  were  due  to  this  acid.  Tiiis  acid 
Jias  later  been  found  iu  other  cases  of  alcaptonuria  by  Fmbden,  Garxier 
and  VoiRiN,  Ogdex,  and  others,  Glycosuric  acid,  isolated  from  alcapton- 
uric urine  first  by  ^Iakshall  and  recently  by  IiEYger,^  is  identical 
with  homogentisic  acid.  Tyrosin  is  considered  as  the  mother-substance  of 
this  acid.  On  the  introduction  of  tyrosin  iu  persons  with  alcaptonuria, 
WoLKOW  and  Baumanx  and  Embuex  observed  a  greater  or  less  increase  in 
t!ie  quantity  of  homogentisic  acid  in  the  urine.  According  to  Wolkow 
and  Baumann  this  acid  is  formed  from  the  tyrosin  by  abnormal  putrefac- 
tive processes  in  the  upper  part  of  the  intestine. 

Homogentisic  acid  is  the  dioxyphenyl-acetic  acid  derived  from  hydro- 
chinon.  On  fusion  with  potash  it  yields  gentisic  acid  (hydrochinon- 
carbonic  acid)  and  hydrochinon.  When  introduced  into  the  intestinal  tract 
of  dogs  it  is  in  part  converted  into  tolu-hydrochinon,  which  is  eliminated 
in  the  form  of  ethereal-sulphuric  acid.     Homogentisic  acid  has  recently 

'  Schultzen  and  Riess,  Chom.  Centralbl.,  1869  ;  Blenderman,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  G.  S.  267;  Baumann.  ibid.,  Bd.  6,  S.  193. 

■  "Wolkow  and  B.uunann,  Zeitsclir.  f.  physiol.  Chem..  Bd.  15;  Emhden,  ibid.,  Bdd. 
17  and  18  ;  Gamier  and  Voirin,  Arch,  de  Physiol.  (5),  Tome  4  ;  Ogdeu,  Zeitschr.  f. 
physiol.  Chem.,  Bd.  20;  Marshall,  Maly's  Jahresber.,  Bd.  17,-  Geyger,  cited  from  Emb- 
den,  1.  c. 


452  ubjjS'E.   . 

been  prepared  synthetically  by  Bai'maxn  and  Frankel,'  starting  with 
gentisic  aldehyde. 

Ilomogentisic  acid  crystallizes  with  1  mol.  water  in  large,  transparent 
prismatic  crystals,  which  become  non-transparent  at  the  temperature  of  the 
room  with  the  loss  of  water  of  crystallization.  They  melt  at  146.5-147°  C. 
They  are  solnble  in  water,  alcohol,  and  ether,  bnt  nearly  insoluble  in  chloro- 
form and  benzol.  Homogentisic  acid  is  optically  inactive  and  non-ferment- 
able. Its  watery  solution  has  the  properties  of  so-called  alcaptonuric  urine. 
It  becomes  greenish  brown  from  the  surface  downward  on  the  addition  of 
very  little  caustic  soda  or  ammonia  with  excess  of  oxygen,  and  on  stirring 
it  becomes  quickly  dark  brown  or  black.  It  reduces  alkaline  copper  solu- 
tions with  even  slight  heat,  and  ammoniacal  silver  solutions  immediately  in 
the  cold.  It  does  not  reduce  alkaline  bismuth  solutions.  It  gives  a  lemon- 
colored  precipitate  with  Millon's  reagent,  which  becomes  light  brick-red 
on  warming.  Among  the  salts  of  this  acid  we  must  mention  the  lead  salt 
containing  water  of  crystallization  and  34.79^  Pb.  This  salt  melts  at 
314-215°  C. 

In  preparing  this  acid  the  strongly  acidified  urine  is  shaken  with  ether. 
The  residue  obtained  on  the  distillation  of  the  ether  is  dissolved  in  water, 
the/solution  heated  to  boiling  and  treated  with  a  lead  acetate  solution 
(1  :  5),  and  the  brown  resinous  precipitate  quickly  separated  by  filtration. 
The  lead  salt  gradually  crystallizes  from  the  filtrate.  This  is  decomposed 
by  sulphuretted  hydrogen,  and  the  acid  obtained  as  crystals  from  the  filtrate 
^fter  carefully  concentrating  the  filtrate  finally  in  vacuo. 

In  regard  to  the  quantitative  estimation  we  proceed  according  to  the  suggestion  of 

N 
Baumann  by  titrating  the  acid  with  a  —  silver  solution.     As  regards  details  of  this 

method  we  must  refer  the  reader  to  the  original  publication.^  Deniges^  has  suggested 
another  method. 

TJroleucic  acid,  CoHioOb,  is,  according  to  Huppert,  probably  a  dioxyphenyllactic 
acid,  CMl3(OH)5.CH2.CH(OH).COOH.  This  acid  was  first  prepared  by  Kirk^  from 
the  urine  of  cliildren  with  alcaptonuria,  which  also  contained  homogentisic  acid.  It 
melts  at  130-133°  C.  Otherwise,  in  regard  to  its  behavior  with  alkalies,  with  access  of 
ftir,  and  also  with  alkaline  copper  solutions  and  ammoniacal  silver  solutions,  and  also 
Millon's  reagent,  it  is  similar  to  homogentisic  acid. 

Oxymadelic  acid,  C^HbO*,  paraoxyphenylglycolic  acid,  HO.C9H4.CH(OH)COOH,  is, 
4is  above  stated,  found  in  the  urine  in  acute  atrophy  of  the  liver.  The  acid  crystallizes 
in  silky  needles.  It  melts  at  163°  C,  dissolves  readily  in  hot  water,  less  in  cold  water, 
and  readily  in  alcohol  and  ether,  but  not  in  hot  benzol.  It  is  precipitated  by  basic  lead 
acetate,  but  not  by  lead  acetate. 

Kynurenic  acid,  CioHtNO-,,  is  an  oxychinolin-carbonic  acid  occurring  in  dog's  urine. 
We  are  not  clear  in  regard  to  the  origin  of  this  acid.  It  seems  not  to  be  formed  in  the 
intestinal  tract,  and  it  is  not  changed  by  putrefaction  bacteria  (Cupaldi).^ 


•  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 
5  Ibid.,  16. 

»  Chem  Centralbl.,  1897,  Bd.  1,  S.  338. 

*  Huppert,  Zeitschr.  f.  physiol.  Chem.,  Bd.  23  ;  Kirk,  Brit.  med.  Journ.,  1886  and 
1888,  Journ  of  Anat.  and  Physiol.,  Vol.  23. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  23.     In  regard  to  kynurenic  acid  see  alsoHuppert- 
Neubauer,  10.  Aufl.,  and  Mendel  and  Jackson,  Amer.  Journ.  of  Physiol.,  Vol.  2. 


URINARY  PIGMENTS  AND   CUROMOOENS.  453 

Urinary  Pigments  and  Chromogens.  The  yellow  color  of  normal  urine 
depends  ])erha])3  u])on  several  pigments,  but  in  greatest  part  upon  ukociikom. 
Besides  this  the  urine  seems  to  contain  a  very  small  quantity  of  ii^mato- 
roRPHYKix  as  a  regular  constituent.  Uroerythrin  also  is  of  frequent 
occurrence  in  normal  urine.  Finally,  tlie  excreted  urine  when  exposed 
to  the  action  of  light  regularly  contains  a  yellow  pigment,  urobilin, 
which  is  derived  from  a  chromogen,  urorilixogen,  by  the  action  of  light 
(Saillet)  and  air  (Jaife,  DiSQUE',and  others).  Besides  this  chromogen, 
urine  contains  various  other  bodies  from  wliich  coloring  matters  may  be 
produced  by  the  action  of  chemical  agents.  Humin  substances  (perhaps  in 
part  from  the  carbohydrates  of  the  urine)  may  be  formed  by  the  action  of 
acids  (v.  Udranszky)  without  regard  to  the  fact  that  such  substances  may 
sometimes  originate  from  the  reagents  used,  as  from  impure  amyl-alcohol 
(v.  Udranszky  ').  To  these  humin  bodies  developed  by  the  action  of  acid 
in  normal  urine  when  exposed  to  the  air  must  be  added  the  uropiiaix  of 
Heller,  the  various  uromelanins,  and  other  bodies  described  by  different 
investigators  (Plos'z,  Thudichum,  Scuunck  ').  Indigo-blue  (uroglaucin 
of  Heller,  urocy'anin,  cy'anurin,  and  other  coloring  matters  of  older 
investigators*)  is  split  off  from  the  indoxyl-snlphuric  acid  or  indoxyl- 
glycuronic  acid.  Red  coloring  matters  may  be  formed  from  the  conjugated 
indoxyl  and  skatoxyl  acids,  and  uroiiodin  (Heller),  urorubin  (Plos'z), 
rROH.EMATiN  (Harley'),  and  perhaps  also  urorosein  (Nencki  and 
Sieber')  probably  have  such  an  origin. 

We  cannot  discuss  more  in  detail  the  different  coloring  matters  obtained 
as  decomposition  products  from  normal  urine.  Ha?matoporpliyrin  has 
already  been  referred  to  in  a  previous  chapter  (VI)  and  will  best  be  described 
in  connection  with  tlie  pathological  pigments.  It  only  remains  to  describe 
urochrom,  urobilin,  and  uroerythrin. 

Urochrom  is  the  name  given  by  Garroi)  to  the  yellow  pigment  of  the 
urine.  Thudichum  '  had  previously  given  the  same  name  to  a  less  pnre 
pigment  isolated  by  himself.  According  to  Garrod  urochrom  is  free  from 
iron,  but  contains  nitrogen.  It  stands,  i';  seems,  in  close  relationship  to 
urobilin,  as  Garrod  has  obtained  a  urobilin-like  pigment  by  the  action  of 

*  Jaffe.  Centralbl.  f.  d.  med.  Wissensch.,  1868  and  1869,  aud  Virchow's  Arch.,  Bd. 
47  ;  Disque,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  2  ;  Saillet,  Revue  de  medecinc,  Tome  17. 
1897. 

«  V.  Udraiisky,  Zeitschr.  f.  pbysiol.  Chem.,  Bdd.  11,  12,  aud  13. 

•Plos'z,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  8;  Thudichum,  Brit.  med.  Journ.,  Vol, 
201,  and  Journ.  f.  prakt.  Chem.,  Bd.  104;  Schuuck,  cited  from  Huppert-Neiibauer, 
10.     Autl.,  p.  509. 

*  See  Huppert-Neubauer,  p.  161. 

'  In  regard  to  this  and  other  red  pigments  see  Huppert-Neubauer,  pp.  593  and  597; 
Neucki  and  Sieber,  .Journ.  f.  prakt.  Chem.  (2).  Bd.  26. 

*  Garrod,  Proceed.  Roy.  Soc,  Vol.  55  ;  Thudichum,  1.  c. 


454  URINE. 

aldehyde  on  nrochrom,  and  Eiya  '  claims  that  nrobilin  yields  a  body  similar 

to  nrochrom  on  carefnl  oxidation  with  permanganate. 

Urochrom  is,  according   to    Garrod,  amorphous,  brown,  very  readily 

soluble  in  water  and  ordinary  alcohol,  but  less  soliible  in  absolute  alcohol. 

It  dissolves  but  slightly  in  acetic  ether,  amyl-alcohol,  and  acetone,  while  it 

is  insoluble  in  ether,  chloroform,  and  benzol.     Urochrom  is  precipitated  by 

lead  acetate,  silver  nitrate,  mercuric  acetate,   phosphotungstic  and   phos- 

phomolybdic  acids.     On  saturating  the  urine  with  ammonium  sulphate  a 

great  part  of  the  urochrom  remains  in  solution.     It  does  not  show  any 

absorption-bands,  and  does  not  fluoresce  after  the  addition  of  ammonia  and 

zinc  chloride.     Urochrom  is  very  readily  decomposed,  with  the  formation 

of  brown  substances,  by  the  action  of  acids. 

Urochrom  is  prepared  according  to  a  rather  complicated  method  which  consists  ia 
saturating  the  urine  with  ammonium  sulphate,  wlien  most  of  the  uroclirom  remains  in 
solution.  The  filtrate  is  treated  with  a  proper  quantity  of  alcohol  when  a  clear,  yellow, 
alcoholic  laj'-er  collects  on  the  salt  solution,  and  this  contains  the  urochrom  and  is  further 
purified  according  to  Garrod.^ 

Urobilin  is  the  pigment  first  iolated  from  the  urine  by  Jaffe  '  and 
which  is  characterized  by  its  strong  fluorescence  and  by  its  absorption- 
spectrum.  A'arious  investigators  have  prepared  from  the  urine  by  different 
methods  pigments  which  differed  slightly  from  each  other  but  behaved 
essentially  like  Jaffe's  urobilin.  Thus  different  urobilins  have  been 
suggested,  such  as  normal,  febrile,  physiological,  and  pathological  urobilins.* 
The  possibility  of  the  occurrence  of  different  urobilins  in  the  urine  cannot 
be  denied;  but  as  urobilin  is  a  readily  changeable  body  and  difficultly 
purified  from  other  urinary  pigments,  the  question  as  to  the  occurrence  of 
different  urobilins  must  still  be  considered  open.  According  to  Saillet  '  no 
nrobilin  exists  originally  in  human  urine,  btit  only  the  mother-substance 
of  the  same,  urobilinogen,  from  which  the  urobilin  is  formed  in  the  excreted 
urine  by  the  influence  of  light. 

Urobilin-like  bodies,  so-called  urobilixoid,  have  been  prepared  from 
bile  pigments  as  well  as  blood  pigments,  and  indeed  by  oxidation  as  well  as 
reduction.  Maly  obtained  his  hydrobilirubin  by  the  reduction  of  bilirubin 
with  sodium  amalgam,  and  Disqx'E  obtained  a  product  which  is  still  more 
similar  to  urobilin,  while  Stokyis  prepared  by  the  oxidation  of  cholecyaniu 
with  a  little  lead  peroxide  a  choletelin  which  acted  very  much  like  urobilin. 
Hoppe-Seyler,  Le  XoiiEL,  Nencki  and  Sieber  have  obtained  urobilinoid 


'  Garrod,  .Journ.  of  Physiol.,  Vol.  21  ;  Riva,  cited  from  Huppert-Neuhauer,  p.  524. 

«L.  c. 

3  Centralbl.  f.  d.  med.  Wisfensch.,  1868  and  1809,  and  Virchow's  Arch.,  Bd.  47. 

*  See  MacMunn,  Proc.  Roy.  Soc,  Vols.  31  and  35  ;  Ber.  d.  deutsch.  chem.  Gesellsch., 
Bd.  14,  and  Journ.  of  Pliysiol.,  Vols.  6  and  10;  Bogomoloff,  Maly's  Jahresber,  Bd.  22  ; 
Eichholz,  Journ.  of  Physiol.,  Vol.  14  ;  Ad.  Jolles,  Pflugcr's  Arch..  Bd.  61. 

'  Revue  de  medecine.  Tome  19,  1897. 


UliOBIIAN.  455 

boilies  by  the  reduction  of  liaiinatin  uud  liannatoporphyrin  witli  tin  or  zinc 
and  liydrochloric  iicid,  while  MacMl'Xn'  obtained  by  tlie  oxidation  of 
haematin  witii  liydrogen  peroxide  in  alcohol  containing  sulphuric  acid  a 
pigment  wliich  seemed  to  be  identical  witli  nrinary  urobilin.  It  is  apparent 
that  all  these  nrobilina  canuot  be  identical. 

Many  investigators  declare  that  urobilin  is  identical  with  hydrobilirabin, 
but  according  to  tlie  researches  of  Hopkins  and  Gaurod'  this  view  is  not 
correct  because,  irrespective  of  other  small  dilTerences,  each  body  has  an 
essentially  distinct  composition.  Hydrobilirubin  contains  C  G4.G8, 
H  0,03,  N"  9.22  (Maly),  while  urinary  urobilin,  on  the  contrary,  contains 
C  63.46,  II  7. 67,  N  4.09<^.  The  urobilin  from  faeces,  stercobilix,  has  the 
same  composition  as  urinary  urobilin  with  4.17^'^  nitrogen. 

Urinary  urobilin  may  not  be  identical  with  hydrobilirubin,  but  this  does 
not  eliminate  the  possibility  that  urobilin,  according  to  the  generally 
admitted  view,  is  derived  from  bilirubin  (although  not  by  simple  reduction 
and  taking  up  water)  in  the  intestine.  Several  physiological  as  well  as 
clinical  observations  ^  speak  for  this  view,  among  which  we  must  mention 
the  regular  appearance  in  the  intestinal  tract  of  stercobilin,  undoubtedly 
derived  from  the  bile-pigments  and  having  the  same  composition  as  urinary 
urobilin;  the  absence  of  urobilin  in  the  urine  of  new-born  infants  and  also  on 
the  complete  removal  of  bile  from  the  intestine;  as  well  as  the  increased 
elimination  of  urobilin  with  strong  intestinal  putrefaction.  On  the  other 
hand  there  are  investigators  who,  basing  their  opinion  on  clinical  observations, 
deny  the  intestinal  origin  of  urobilin  and  claim  that  the  urobilin  is  derived 
from  a  transformation  of  the  bilirubin  not  in  the  intestine,  by  an  oxidation 
of  the  same  or  also  by  a  transformation  of  the  blood-pigments.*  The  possi- 
bility of  a  different  mode  of  formation  of  urinary  urobilin  in  disease  is  not 
to  be  denied;  but  there  is  no  doubt  that  this  pigment  is  formed  from  the 
bile-pigments  in  the  intestine  under  physiological  conditions. 

The  quantity  of  urobilin  in  the  urine  under  physiological  conditions  is 
very  variable.  Saillet  found  30-130  milligrammes  and  G.  Hoppe-Seyler 
80-140  milligrammes  in  one  day's  urine. 

'Maly,  Ann.  d.  Cliem.  u.  Pharm.,  Bd.  163;  Disque,  Zeitschr.  f.  physiol.  Chem., 
Bd.  2;  Stokvis,  Centralbl.  f.  d.  med.  Wissensch.,  1873,  S.  211  and  449;  Hoppe-Seyler 
Ber.  d.  deutscb.  chem.  Gescllsch.,  Bd.  7;  Le  Nobel,  Pflliger's  Arcb.,  Bd.  40;  Nencki 
and  Sieber,  JMonatsiiefle  f.  Chem.,  Bd.  9,  and  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24  ; 
MacMunn,  Proc.  Hoy.  Sec,  Vol.  31. 

»  Joiirn.  of  Physiol.,  Vol.  22. 

»  See  Fr.  Miiller,  Schles.  Gesellsch.  f.  vaterl.  Kultur,  1892  ;  D.  Gerhardt,  "  Ueber 
Hydrobilinibiii  nnd  seine  Bezieh.  zum  Ikterus "  (Inaug.-Diss.,  Berlin,  1889);  Beck, 
Wieu.  klin.  Wocbeuschr.,  189.3;  Harley,  Brit.  Med.  Journ.,  1896. 

*  In  regard  to  the  various  theories  as  to  the  formation  of  urobilin  see  Ilarley,  Bril. 
Med.  Journ.,  1896;  A.  Katz,  Wieu.  Med.  Wochenschr.,  1891,  Nos.  28-32;  Grimm, 
Vircbow's  Arch.,  Bd.  132  ;  Zoja,  Conferenze  cliniche  italiane,  Ser.  1  a.  Vol.  1. 


456  URINE. 

We  have  nnmerons  observations  on  the  elimination  of  urobilin  in  disease, 
especially  by  Jaffe,  Disque,  Dretfuss-Brissac,  Gerhardt,  G.  Hoppe- 
Setler,'  and  others.  The  quantity  is  increased  in  hemorrhage  in  snch 
diseases  where  the  blood-corpuscles  are  dostroyed,  as  after  the  action  of 
certain  blood-poisons,  such  as  antifibrin  and  antipyrin.  It  is  also  increased 
iu  fevers,  heart-tronbles,  lead  colic,  atrophic  liver  cirrhosis,  and  is  especially 
abundant  in  so-called  urobilin  icterus. 

The  properties  of  urobilin  may  be  different,  depending  upon  the  method 
of  preparation  and  the  character  of  the  urine  used,  therefore  only  the  most 
important  properties  will  be  given.  Urobilin  is  amorjihous,  brown,  reddish- 
brown,  red,  or  reddish  yellow,  depending  upon  method  of  preparation.  It 
dissolves  readily  in  alcohol,  amylalcohol,  and  chloroform,  but  less  readily  in 
ether  or  acetic  ether.  It  is  less  soluble  in  water,  but  the  solubility  is 
augmented  in  the  presence  of  neutral  salts.  It  may  be  completely  precipi- 
tated from  the  urine  by  saturating  with  ammonium' sulphate  especially  after 
the  addition  of  sulphuric  acid  (Mehy*).  It  is  soluble  in  alkalies,  and  is 
precipitated  from  the  alkaline  solution  by  the  addition  of  acid.  It  is  partly 
dissolved  by  chloroform  from  an  acid  (watery-alcoholic)  solution;  alkali 
solutions  remove  the  urobilin  from  the  chloroform.  The  neutral  or  faintly 
alkaline  solutions  are  precipitated  by  certain  metallic  salts  (zinc  and  lead), 
but  not  b}^  others,  snch  as  mercuric  sulphate.  Urobilin  is  precipitated  from 
the  urine  by  phosphotungstic  acid.  It  does  not  give  Gmelin's  test  for  bile- 
pigments.  It  gives,  on  the  contrary,  a  reaction  which  may  be  mistaken  for 
the  biuret  test,  by  the  action  of  copper  sulphate  and  alkali.' 

Xeutral  alcoholic  urobilin  solutions  are  in  strong  concentration  brownish 
yellow,  in  great  dilution  yellow  or  rose-colored.  They  have  a  strong  green 
fluorescence.  The  acid-alcoholic  solutions  are  brown,  reddish  yellow,  or 
rose-red,  according  to  concentration.  They  are  not  fluorescent,  but  show 
a  faint  absorption-band,  y,  between  h  and  F,  which  borders  on  F,  or  in 
greater  concentration  extends  over  F.  The  alkaline  solutions  are  brownish 
3'ellow,  yellow,  or  (the  ammoniacal)  yellowish  green,  according  to  concen- 
tration. If  some  zinc-chloride  solution  is  added  to  an  ammoniacal  solution, 
it  becomes  red  and  shows  a  beautiful  green  fluorescence.  This  solution,  as 
also  that  made  alkaline  with  fixed  alkalies,  shows  a  darker  and  more 
sharply  defined  band,  6,  between  h  and  F,  almost  midway  between  E 
and  F.  If  a  sufficiently  concentrated  solution  of  urobilin  alkali  is  carefully 
acidified  with  saphuric  acid  it  becomes  cloudy  and  shows  a  second  band 

'  In  regard  to  the  literature  on  tliis  subject  we  refer  the  reader  toD.  Gerhardt,  "Ueber 
Hydrobilirubiu  und  seiue  Beziehungen  zum  Ikteriis"  (Berlin,  1889),  and  also  G.  Hoppe- 
Seyler,  Virchow's  Arch.,  Bd.  124. 

'  Journ.  de  Pharm.  et  Chim.,  1878,  cited  from  Maly's  Jahresber.,  Bd.  8. 

'  See  Salkowski,  Berlin,  klin.  Wochenschr.,  1807,  and  Stokvis,  Zeilschr.  f.  Biologic, 
Bd.  34. 


rUEPARATlON  AND  EST  IMA  T  ION  OF  UROBILIN.  457 

exactly  at  /;  and  connected  with  ;' by  a  sliiulow  (TiAiaiOit  and   TIopkixs, 
S.villet'). 

Urobilinogen  is  colorless  or  is  only  slightly  colored.  Like  urobilin  it  is 
l)recipitated  from  the  urine  by  saturating  with  amnioninrn  sulphate. 
According  to  Sah.let  it  may  be  extracted  by  acetic  ether  from  urine  acidi- 
fied with  acetic  aoid.  It  dissolves  also  in  chloroform,  ethyl  ether,  and 
amyalcohol.  It  shows  no  absorption-bands,  and  is  readily  converted  into 
urobilin  by  the  inflnence  of  sunlight  and  oxygen. 

In  preparing  urobilin  from  normal  urine,  precipitate  the  urine  with 
basic  lead  acetate  (Jaffe),  wash  the  precipitate  witli  water,  dry  at  the 
ordinary  temperature,  then  boil  it  with  alcohol,  and  decompose  it  when  cold 
with  alcohol  containing  sulphuric  acid.  The  filtered  alcoholic  solution  is 
diluted  with  water,  saturated  with  ammonia,  and  then  treated  with  zinc- 
chloride  solution.  This  new  precipitate  is  washed  free  from  chlorine  with 
Avater,  boiled  with  alcohol,  dried,  dissolved  in  ammonia,  and  this  solution 
precipitated  with  sugar  of  lead.  This  precipitate,  which  is  washed  with 
water  and  boiled  with  alcohol,  is  decomposed  by  alcohol  containing  sul- 
phuric acid,  the  filtered  alcoholic  solution  is  mixed  witii  \  vol.  cliloroform, 
diluted  with  water,  and  shaken  repeatedly,  but  not  too  energetically.  The 
urobilin  is  taken  up  by  the  chloroform.  This  last  is  washed  once  or  twice 
with  a  little  water  and  then  distilled,  leaving  the  urobilin.  The  pigment 
may  be  precipitated  directly  from  tlie  urine  rich  in  urobilin  by  ammonia 
and  zinc  chloride,  and  the  precipitate  treated  as  above  decribed  (Jaffe). 

The  method  suggested  by  Mehy  (precipitation  with  ammonium  sul- 
phate) has  been  modified  by  Garrod  and  Hopkins  in  that  they  first  remove 
tlie  uric  acid  by  saturating  with  ammonium  chloride  and  then  saturating 
the  filtrate  with  ammonium  sulpliate.  The  precipitated  urobilin  is  thus 
made  purer  than  by  saturating  with  the  sulphate  directly.  The  urobilin  is 
extracted  from  the' dried  precipitate  by  a  great  deal  of  water,  reprecipitated 
by  ammonium  sulphate,  and  this  procedure  repeated  several  times  if  neces- 
sary. The  dried  precipitate  finally  obtained  is  dissolved  in  absolute  alcohol. 
In  regard  to  small  details,  and  to  a  second  method  suggested  by  these  experi- 
menters, we  refer  to  the  original  work.' 

Saillet  extracts  the  urobilinogen  from  the  urine  by  shaking  with 
acetic  ether,  using  a  kerosene-oil  light.' 

The  color  of  the  acid  or  alkaline  solution,  the  beautifnl  fluorescence  of 
the  ammoniacal  solution  treated  with  zinc  chloride,  and  the  absorption- 
bauds  of  the  spectrum,  all  serve  as  means  of  detecting  urobilin.  In  fever- 
urines  the  urobilin  may  be  detected  directly  or  after  the  addition  of 
ammonia  and  zinc  chloride  by  its  spectrum.  It  may  also  sometimes  be  de- 
tected in  normal  urine,  either  directly  or  after  the  urine  has  stood  exposed  to 
the  air  until  the  chromogen  has  been  converted  into  urobilin.  If  it  cannot 
be  detected  by  means  of  the  spectroscope,  then  the  urine  may  be  treated 
with  a  mineral  acid  and  shaken  with  ether  or,  still  better,  with  amylalcohol. 
The  amylalcohol  solution  is,  either  directly  or  after  addition  of  a  strongly 
ammoniacal  alcoholic  solution  of  zinc  chloride,  tested  spectroscopically.     If 

'  Garrod  and  Ilopkius,  Jouiu.  of  Physiol.,  Vol.  20;  Saillet,  1.  c. 

»  Jomu.  of  Phvsiol.,  Vol.  20. 

^  lu  nguid  to  tliis  aud  other  methods  we  must  refer  the  reader  to  special  works. 


458  URINE. 

the  tarobilin  cannot  be  detected  in  this  way,  the  pigment  may  be  isolated 
by  ammonium  sulphate  according  to  the  above-described  method  of  Gakrod 
and  Hopkins. 

In  the  quantitative  estimation  of  urobilin  we  proceed  as  follows,  accord- 
ing to  G.  Hoppe-Seyler:  '  100  c.c.  of  the  urine  is  acidified  with  sulphuric 
acid  and  saturated  with  ammonium  sulphate.  The  precipitate  is  collected 
on  a  filter  after  some  time,  washed  with  a  saturated  solution  of  ammonium 
sulphate,  and  repeatedly  extracted  with  equal  parts  alcohol  and  chloroform 
after  pressing.  The  filtered  solntion  is  treated  with  water  in  a  separatory 
funnel  until  the  chloroform  separates  well  and  becomes  clear.  The  chloro- 
form solution  is  evaporated  on  the  water-bath  in  a  weighed  beaker,  the 
residue  dried  at  100°  C,  and  then  extracted  with  ether.  The  ethereal 
extract  is  filtered,  the  residue  on  the  filter  dissolved  in  alcohol,  and  trans- 
ferred to  the  beaker  and  evaporated,  then  dried  and  weighed.  According  to 
this  method  G.  Hoppe-Seyler  found  0.08-0.14  grm.  urobilin  in  one  day's 
urine  of  a  healthy  person,  or  an  average  of  0.123  grm. 

Urobilin  may  also  be  determined  spectro-photometrically  according  to  Fr.  Muller 
or  to  Saillet.''^  According  to  Saillet  the  limit  for  the  perceptibility  of  the  absorption- 
bands  of  an  acid  urobilin  solution  lies  in  a  concentration  of  1  milligramme  urobilin  in  22 
c.  c.  solntion  when  the  thickness  of  the  layer  of  fluid  is  15  mm.  In  a  quantitative  esti- 
mation the  urobilin  solution  is  diluted  to  this  limit  and  then  the  quantity  of  urobilin 
calculated  from  the  extent  of  dilution.  The  freshly  voided  urine,  shielded  from  light, 
is  acidified  with  acetic  acid,  completely  extracted  in  kerosene-oil  light  with  acetic  ether, 
and  the  dissolved  urobilinogen  oxidized  to  urobilin  with  nitric  acid.  On  the  addition  of — 
ammonia  and  shaking  with  water  the  urobilin  passes  into  the  watery  solution.  This  is 
acidified  with  hydrochloric  acid  and  diluted  until  the  above  limit  is  reached. 

Uroerythrin  is  the  pigment  which  often  gives  the  beautiful  red  color  to 
the  urinary  sediments  {sedimentum  lateritiutn).  It  also  frequently  occurs, 
although  only  in  very  small  quantities,  dissolved  in  normal  urines.  The 
quantity  is  increased  after  great  muscular  activity,  after  profuse  perspira- 
tion, immoderate  eating,  or  partaking  of  alcoholic  drinks,  as  well  as  after 
digestive  disturbances,  fevers,  circulation  disturbances  of  the  liver,  and  in 
many  other  pathological  conditions. 

Uroerythrin,  which  has  been  especially  studied  by  Zoja,  Eiva,  and 
Garrod,'  has  a  pink  color,  is  amorphous  and  is  very  quickly  destroyed  by 
light,  especially  when  in  solntion.  The  best  solvent  is  amylalcohol;  acetic 
ether  is  not  so  good,  and  alcohol,  chloroform,  and  water  are  even  less  val- 
uable. The  very  dilute  solntions  show  a  pink  color;  but  on  greater  concen- 
tration they  become  reddish  orange  or  fire-red.  They  do  not  fluoresce  either 
directly  or  after  the  addition  of  ammoniacal  solution  of  zinc  chloride,  but 
they  have  a  strong  absorption,  beginning  in  the  middle  between  D  and  E 
and  extending  to  about  F.,  and  consisting  of  two  bands  which  are  connected 
by  a   shadow  between  E  and  h.     Concentrated   salphnric   acid   colors  a 

'  Virchow's  Arch.,  Bd.  124. 

'  Fr.  Milller,  see  Huppert-Neubaucr,  p.  861  ;  Saillet,  1.  c. 

'  Zojn,  Arch.  Ital.  di  clinica  nied.,  1893,  and  Centralbl.  f.  d.  mcd.  Wissensch.,  1892; 
Riva,  Gaz.  mcd.  di  Torino,  Anno  43,  cited  from  Maly's  Jahresber.,  Bd.  24 ;  Garrod, 
Journ.  of  Physiol.,  Vols.  17  and  21. 


REDUCINO  SUBSTANCES  IN  THE   UlilNE.  459 

uroerjthriii  solution  a  beautiful  carmine  red;  hydrochloric  acid  gives  a  pink 
color.  Alkalies  make  its  solutions  grass-green,  and  often  a  play  of  colors 
from  pink  to  purple  and  blue  is  observed. 

lu  prt'pariii!^  uroerythrin  the  sediment,  iiccordiiig  to  Gauuod,  is  dissolved  in  water  at 
a  gentle  heiit  and  salnraled  with  aiumoniuni  chloride,  which  precipitates  the  pigment 
with  the  iimmoninm  mate.  This  is  puritied  by  rei)eated  solution  in  water  jiud  precipi- 
tation with  ammonium  chloride  until  all  the  urobilin  is  removed.  The  precipitate  is 
finally  extracted  on  the  lilter  in  the  dark  with  warm  water,  tillered,  diluted  with  water, 
any  htematoporphyrin  remaining  is  removed  by  sliaking  with  chloroform,  faintly  acidi- 
fied with  acetic  acid  and  shaken  with  chloroform,  which  takes  up  the  uroerythrin.  The 
chloroform  is  evaporated  in  the  dark  at  a  gentle  heat. 

Volatile  fiitty  acids,  ^\xc\xii%{orn\\Ci\i:\i\.  acetic  acid,  and  perhaps  also  butyric  acid,  occur 
under  normal  coiidilions  in  human  urine  (v.  Jaksch),  also  in  that  of  dogs  and  herbivora 
(SciiOTTEX).  The  acids  poorest  in  carbon,  such  as  formic  acid  and  acetic  acid,  are  more 
constant  in  the  Iwdy  than  those  richer  in  carbon,  and  therefore  the  relatively  greater 
part  of  these  pass  luichangud  into  the  urine  (Schotten).  Normal  human  urine  contains 
besides  these  bodies  others  which  yield  acetic  acid  when  oxidized  by  potassium  dichro- 
mate  and  sulphuric  acid  (v.  Jaksch).  The  quantity  of  volatile  fatty  acids  in  normal 
urine  is,  according  to  v.  Jakscfi,  0.008-0.009  grm.  per  24  hours,  and  according  to 
V.  RoKiTA.NSKY  0.054  grm.  The  quantity  is  increased  by  exclusive  farinaceous  food 
(HuKiTANSKY),  also  in  fever  and  in  certain  diseases  of  the  liver  (v.  Jakscu).  It  is  also 
increased  in  leucaemia  and  in  many  cases  of  diabetes  (v.  Jaksch).  Large  amounts  of 
volatile  fatly  acids  are  produced  in  the  alkaline  fermentation  of  the  urine,  and  the  quan- 
tity is  6-15  times  as  large  as  in  normal  urine  (Salkowski  ').  Non-volatile  fatty  acida 
have  been  detected  as  normal  constituents  of  urine  by  K.  Mohner  and  Hybbinette.' 

Paralactic  Acid.  It  is  claimed  that  thi^^  acid  occurs  in  the  urine  of  health}'  persons 
after  very  fatiguing  marches  (Colasanti  and  Moscatelli).  It  is  tound  in  larger 
amounts  in  the  urine  in  acute  phosphorus-poisoning  or  acute  yellow  atrophy  of  the  liver 
(ScHULTZEN  and  RiESs).  According  to  the  investigations  of  Hoppe-Seylek,  Araki, 
and  V.  Terray  lactic  acid  passes  into  the  urine  as  soon  as  the  supply  of  oxygen  is 
decreased  in  any  way.  Minkowski*  has  shown  that  lactic  acid  occurs  in  the  unue  in 
large  (luantities  on  the  extirpation  of  the  liver  of  birds. 

Glycero-phospJioric  acid  occurs  as  traces  in  the  \irine,^  and  it  is  probably  a  decomposi- 
tion product  of  lecithin.  The  occurrence  of  succinic  acid  in  normal  urine  is  a  subject 
of  discussion. 

Carbohydrates  and  Reducing  Substances  in  the  Urine.  The  occurrence 
of  grape-sugar  as  traces  in  normal  nrine  is  highly  probable,  as  the  investi- 
gations of  Brucke,  Abeles,  and  v.  Udranszky  show.  The  last  investi- 
gator has  also  shown  the  habitual  occurrence  of  carbohydrates  in  the  nrine, 
and  their  presence  has  been  positively  proved  by  the  investigations  of 
Baumann  and  Wedexski,  and  especially  by  Baisch.  Besides  glucose 
normal  urine  contains,  according  to  Baisch,  another  not  well-studied 
variety  of  sugar;  according  to  Lemaire,  probably  isomaltose,  and  besides 
this  a  dextrin-like  carbohydrate  (animal  gum),  as  shown  by  Landweiir, 
Wedexski,  and  Baisch.' 

'  V.  Jaksch,  Zeitschr.  f.  physiol.  Chem.,  Bd.  10  ;  Schotten,  1.  c,  Bd.  7;  Rokitansky, 
Wien.  med.  Jahrbuch,  1887  ;  Salkowski,  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

»  Skand.  Arch.  f.  Physiol.,  Bd.  7. 

'Colasanti  and  Moscatelli,  Moleschott's  Untersuch.,  Bd.  14;  Schultzen  and  Reis3, 
Chem.  Centralbl.,  1869;  Araki,  Zeitschr.  f.  physiol.  Chem.,  Bdd.  15,  16,  17,  19.  See 
also  Irisawa,  ibid.,  Bd.  17;  v.  Terray,  Pllliger's  Arch.,  Bd.  65.  See  also  Schiltz, 
Zeitschr.  f.  physiol.  Chem.,  Bd.  19;  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bdd. 
21  and  31. 

*  See  Pasqualis,  Maly's  Jahresber.,  Bd.  24. 

*  Lemaire,  Zeitschr.  f.  physiol.  Chem.,  Bd.  21 ;  Baisch,  ibid.,  Bdd.  18,  19,  and  20; 


460  VlilNE. 

Besides  traces  of  sugar  and  the  previously  mentioned  reducing  sub- 
stances, nric  acid  and  creatinin,  the  urine  contains  still  other  reducing 
substances.  These  last  are  probably  (Fluckiger)  conjugated  combinations 
of  ghjcnronic  acid,  C^Hj^O, ,  which  closely  resembles  sugar.  The  reducing 
power  of  normal  urine  corresponds,  according  to  various  investigators,  to 
1.5-5.96  p.  m.  grape-sugar.' 

Glycuronic  Acid,  C.H,„0,  or  CHO.(CH.OH),.OOOH.  This  acid  may 
be  converted  into  saccharic  acid,  C,Hj„Og ,  by  the  action  of  bromine 
(Thieefelder),  and  it  seems  to  occupy  an  intermediate  position  between 
this  acid  and  gluconic  acid,  C,H,^0,.  It  is  a  derivative  of  glucose,  and 
Fischer  and  Piloty  have  prepared  it  synthetically  by  the  reduction  of 
saccharo-lactonic  acid.  Further  reduction  yields  gulonic  acid  lacton 
(Thierfelder).  Glycuronic  acid  is  an  intermediate  metabolic  product, 
and  it  occurs  in  the  urine  only  when  it  is  protected  from  combustion  in  the 
animal  body  by  combining  with  other  bodies.  Such  conjugated  combina- 
tions with  indoxyl,  skatoxyl,  and  phenols  occur  probably  normally  in  very 
small  quantities  in  human  urine.  This  acid  as  conjugated  gl3'curonic  acids 
passes  in  large  quantities  into  the  urine  after  the  administration  of  various 
therapeutic  agents  or  certain  other  substances.  Thus  Schmiedeberg  and 
MEY:|}k  found  campho-glycuronic  acid  in  the  urine  after  partaking  of 
camphor,  and  v.  Mering*  showed  the  presence  of  urochloralic  acid  (see 
Casual  Constituents  of  the  Urine)  after  the  administration  of  chloral 
hydrate.  According  to  Schmiedeberg  ^  glycuronic  acid  seems  to  occur  in 
cartilage  because  it  is  contained  in  chondrosin,  a  cleavage  product  of 
chondroitin-sulphuric  acid.  It  is  also  found  in  the  artist's  color  "  jaune 
indien,"  Avhich  contains  the  magnesium-salt  of  euxanthic  acid  (euxan- 
thon-glycuronic  acid).  On  heating  this  acid  with  water  to  120-125°  C.  it 
splits  into  euxanthin  and  glycuronic  acid,  and  it  is  the  most  available 
material  for  the  preparation  of  glycuronic  acid  (Thierfelder).  Another 
acid,  isomeric  with  the  ordinary  glycuronic  acid,  has  been  found  in  the 
urine  in  certain  cases  (see  Casual  Constituents  of  the  Urine). 

Glycuronic  acid  is  not  crystalline,  but  is  obtained  only  as  a  syrup.  It 
dissolves  in  alcohol  and  is  easily  soluble  in  water.  If  the  watery  solution  is 
boiled  for  an  hour,  the  acid  is  in  part  (20^)  converted  into  the  anhydride 
glycuron,  CgHgOj ,  which  is  crystalline,  soluble  in  water,  but  insoluble  in 
alcohol.     The  alkali  salts  of  this  acid  are  crystalline.     The  neutral  barium 

Treupel,  ibid.,  Bd.  IG.  These  articles  contain  references  to  the  work  of  other  inves- 
tigators. 

'  FlUckiger,  Zeitschr.  f.  physiol.  Chem.,  Bd.  9.     See  also  IIuppcrt-Neiibaucr,  p.  72. 

2  Tijierfelder,  Zeitschr.  f.  physiol.  Chem.,  Bdd.  11,  13,  and  15  ;  Fischer  and  Piloty, 
Ber.  d.  deutsch.  chem,  Gesellsch.,  Bd.  24;  Schmiedeberg  and  Mej'er,  Zeitschr.  f. 
physiol.  Chem.,  Bd.  3  ;  v.  JMering,  ibid.,  Bd.  6. 

»  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28. 


ORGANIC  COMBINATIONS  CONTAINING  SULPHUR.  461 

salt  is  amorphous,  soluble  in  water,  but  is  precipitated  by  alcoliol.  If  a 
concentrated  solution  of  the  acid  is  saturated  with  barium  liydrate,  the 
basic  barium  salt  separates.  The  neutral  lead  salt  is  soluble  in  water,  but 
the  basic  salt  is,  on  the  contrary,  insoluble.  The  acid  is  dextrogyrate  and 
rednces  copper,  silver,  and  bismuth  salts.  It  does  not  ferment  with  yeast. 
Olycuronic  acid  gives  the  furfnrol  reaction  and  acts  like  a  pentose  when 
tested  with  phloroglucin-hydrochloric  acid.  AVith  phenylhydrazin  potas- 
sium glycnronate  gives  a  llaky  yellow  precipitate  of  microscopic  needles 
which  melt  at  114-115°  C.  The  reports  in  regard  to  the  behavior  of 
glycuronic  acid  with  this  test  are  very  contradictory.' 

All  conjugated  glycuronic  acida  are  Irevo-rotatory,  while  glycuronic  acid 
itself  is  dextro-rotatory.  They  are  split  into  glycuronic  acid  and  the  several 
other  groups  by  the  addition  of  water.  A  few  of  the  conjugated  glycuronic 
acids,  such  as  the  urochloralic  acid,  reduce  copper  oxide  and  certain  other 
metallic  oxides  in  alkaline  solution,  and  therefore  they  may  interfere  with 
the  detection  of  sugar  in  the  urine. 

Glycuronic  acid  may  be  prepared  from  urocliloralic  acid  or  campho- 
glycuronic  acid  by  boiling  with  a  mineral  acid.  It  may  be  prepared  more 
easily  by  heating  euxanthic  acid  with  water  in  a  Papix's  digester  to 
120-125°  C.  for  an  hour  and  evaporating  the  watery  solution  at  +  40°  C. 
The  anhydride  which  crystallizes  is  gradually  removed,  the  mother-liquor 
diluted  with  water  and  boiled  for  a  time  to  convert  a  second  portion  of  acid 
into  anhydride,  and  then  evaporated  at  about  -|-  40 '  C.  This  is  continued 
until  nearly  all  the  acid  is  converted  into  anhydride.  The  anhydride  may 
then  be  further  purified. 

Organic  combinations  containing  sulphur  of  unknown  kind,  which  may  in  small  part 
consist  of  sulphocyanide^,  0.04  (Gscheidlen)-O.II  p.  m.  (I.  Munk),'  cystin.  or  bodies 
related  to  it,  taurin  ihrivativts,  chondroitin-sulphuric  acid,  protein  bodies,  and  oxyproteic 
acid,  are  found  in  hunian  as  well  as  in  animal  urines.  The  sulphur  of  these  mostly 
unknown  combinations  has  been  called  "neutral,"  to  differentiate  it  from  the  "acid" 
sulphur  of  the  sulphate  and  ethereal-sulphuric  acids  (Salkowski').  The  neutral  sul- 
phur in  normal  urine  as  determined  by  Sai.kowski  is  15,'?,  by  Stadtuagen  13.3-14.5'J, 
and  by  Lepine  20^  of  the  total  sulphur.  In  starvation,  according  to  Fu.  Mulleu,  the 
absolute  and  relative  quantities  increase.  According  to  IIefkteu  the  quantity  is 
greater  with  a  bread  diet  than  with  a  meat  diet.  E.xcessive  muscular  exercise  increases 
the  elimination  of  ti.e  acid  as  well  as  the  neutral  sulphur  (Bk.ck  and  Benedikt, 
McNK'').  The  quantit}'  of  neutral  sulphur  also  increases  with  insufficient  supply  of 
oxygen  (Reale  and  Boeri),  in  chloroform  narcosis  (Kast  and  Mkstkr).  and  also  after 
the  introduction  of  sulphur  (Presch  and  Yvon  ').  According  to  Lupine  a  part  of  the 
neutral  sulphur  is  more  readily  oxidized  (directly  with  chlorine  or  bromine)  into  sul- 

'  For  literature  see  Hammarsten,  Zeitschr.  f.  physiol.  Chem.,  Bd.  19,  S.  30,  and 
Roos,  ibid.,  Bd.  15.  S.  525. 

*  Gscheidlen,  Plliiger's  Arch.,  Bd.  14  ;  Munk,  Virchow's  Arch.,  Bd.  69. 
3  Ibid.,  Bd.  58,  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 

*  Stadthageu,  Virchow's  Arch.,  Bd.  100;  Lepine,  Compt.  rend.,  Tomes  91  and  97  ; 
Fr.  MUller,  Berlin,  klin.  "Wochenschr.,  1SS7  ;  Heffter.  Ptluger's  Arch.,  Bd.  38;  Beck 
and  Benedikt,  Maly's  Jahresber.,  Bd.  22,  S.  223;  Munk,  Du  Bols-Reymond's  Arch., 
1895. 

'  Reale  and  Boeri,  Maly's  Jahresber.,  Bd.  24;  Kast  and  Mester,  Zeitschr.  f.  klin.  ^Med., 
Bd.  18  ;  Presch.  Viichows  Arch..  Bd.  119  ;  Yvon,  Arch,  de  Physiol.  (5),  Tome  10. 


462  URINE. 

pburic  acid  than  the  otlier,  which  is  first  converted  into  sulphuric  acid  after  fusing  with 
potash  and  saltpetre.     According  to  the  investigations  of  W.  Smith  '  it  is  probable  that 
the  most  unoxidizable  part  of  the  neutral  sulphur  occurs  as  sulpho-acids.    An  increased 
elimination  of   neutral  sulphur  has  been  observed  in  various  diseases,  such  sis  pneu-  ■ 
monia,  cysliuuria,  and  especially  where  the  flow  of  bile  into  the  intestine  is  prevented. 

Harnack  and  Kleine'  have  arrived  at  the  conclusion,  from  numerous  determina- 
tions of  the  sulphur  of  the  urine,  that  not  only  is  the  total  sulphur  genenilly  propor- 
tionate to  the  total  nitrogen,  but  likewise  the  relationship  between  oxidized  sulphur  and 
total  sulphur  is  always  proportionate  to  that  between  urea  and  the  total  nitrogen.  The 
more  unoxidized  sulphur  is  eliminated,  the  moie  do  we  find  in  the  urine  an  abundance 
of  nitrogeneous  compounds,  not  urea.  In  healthy  persons  on  a  mixed  diet  they  found 
that  l9-24'?of  the  total  sulphur  was  organic  sulphur.  In  disease  the  percentage  is  in 
part  dependent  upon  the  quantity  of  food,  which  prevents  any  conclusion  to  be  drawn 
as  to  tlie  influence  of  kind  and  extent  of  disease.  With  continuous  severe  dyspnoea,  the 
percentage  of  organic  sulphur  may  nevertheless  rise  to  AA.%. 

According  to  Benedikt^  the  absolute  value  for  the  non-oxidizable  sulphur  varies 
only  within  narrow  limits,  and  it  is  much  less  dependent  upon  the  extent  of  proteid 
metabolism  than  upon  the  sulphuric-acid  value.  The  relative  value  depends,  in  the 
first  place,  upon  the  extent  of  sulphuric-acid  elimination,  and  correspondingly,  it  may 
be  smaller  with  extensive  proteid  metabolism  and  greater  with  a  diminished  proteid 
metabolism.  Benedikt  is  of  the  opinion  that  the  neutral  sulphur  combinations,  per- 
haps analogous  to  the  alloxuric  bodies,  have  their  origin  in  the  specific  destruction  of 
certain  tissue  constituents,  which  are  always  decomposed  in  rather  uniform  quanti- 
ties. 

The  total  quantity  of  sulphur  in  the  urine  is  determined  by  fusing  the  solid  urinary 
residue  with  saltpetre  and  caustic  alkali.  The  quantity  of  neutral  sulphur  is  deter- 
mined as  the  diflereuce  between  the  total  sulphur  and  the  sulphur  of  the  sulphate  and 
ethereal-sulphuric  acids.  The  readily  oxidizable  part  of  the  neutral  sulphur  is  deter- 
mined by  oxidation  with  bromine  or  potassium  chlorate  and  hydrochloric  acid  (Lefine, 
Jeroie'*). 

Sulphuretted  hydrogen  occurs  in  lu-ine  onl}^  under  abnormal  conditions  or  as  a  de- 
composition product.  Sulphuretted  hydrogen  may  be  produced  from  the  neutral 
sulphur  of  the  organic  substances  of  the  urine  by  the  action  of  certain  bacteria  (Fk. 
MtJLLER,  Salkowski^).  Other  investigators  have  given  hyposulpJiites  as  the  source  of 
the  sulphuretted  hydrogen.  The  occurrence  of  hyposulphites  in  normal  human  urine, 
which  is  asserted  by  Hefpter,  is  disputed  by  Salkowski  and  Presch.'*  Hyposul- 
phites occur  constantly  in  cat's  urine  and,  as  a  rule,  also  in  dog's  urine. 

Organic  combinations  containing  pliosphorns  (glycero-phosphoric  acid,  phosphocarnic 
acid  (Rockwood),  etc.), which  yield  phosphoric  acid  on  fusing  with  saltpetre  and  caustic 
alkali,  are  also  found  in  urine  (Lf.pine  and  Etmonnet,  Oertel'').  With  a  total  elimi- 
nation of  about  2.0  grms.  total  PjOs,  Oertel  found  on  an  average  about  0.05  grms. 
PjOs  as  phosphorus  in  orL^anic  combination. 

Enzymes  of  various  kinds  have  been  isolated  from  the  urine.  Among  these  we  may 
mention  pepsin  (Brccke  and  other.s),  diastatic  enzyme  (Cohnheim  and  others).  The 
occurrence  of  rennin  and  trypsin  in  the  urine  is  doubtful.* 

Mucin.  The  nubecula  consists,  as  shown  by  K.  Morner,'  of  a  mucoid  which  con- 
tains 12.74^  N  and  2.3^  S.  This  mucoid,  which  apparently  originates  in  the  urinary 
passages,  may  pass  to  a  slight  extent  into  solution  in  the  urine.  In  regard  to  the  nature 
of  the  mucins  and  nucleoalbuinins  otlicrwise  recurring  in  the  urine  we  refer  the  reader 
to  the  pathological  constituoiUs  of  the  mine. 

'  Lepine,  1.  c;  Smith,  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 

»  Zeitschr.  f.  Biologic,  Bd.  37. 

3  Zeitschr.  f.  klin.  Med.,  Bd.  36. 

■•  Jerome,  Pflilger's  Arcli.,  Bd.  60. 

'  Fr.  Mliller,  Berlin,  klin.  Wochenschr.,  1887  ;  Salkowski,  ibid.,  1888. 

*  Heffter,  Pfluger's  Arch.,  Bd.  38;  Salkowski,  ibid.,  Bd.  39;  Presch,  Virchow's 
Arch..  Bd.  119. 

'  Rockwood,  Du  Bois-Reymond's  Arch.,  ISO.'i ;  Oertel,  Zeitschr.  f.  physiol.  Chem., 
Bd.  26,  which  cites  the  other  works. 

*  In  regard  to  the  literature  on  enzymes  in  the  urine  see  Huppert-Neubauer,  p.  599. 
,    »  Skand.  Arch.  f.  Physiol.,  Bd.  6. 


CULOlilDEa.  463 

Oryproteic  arid  is  the  name  given  by  Bondza'Nski  and  Gottmeb  to  a  nitrogenous 
ficid  containing  sulplnir,  whose  existence  in  human  urine  was  first  suggested  by  Topkeu. 
It  seems  to  be  a  normal  constituent  of  human  and  dog's  urine,  but  is  found  lo  a  much 
greater  extent  in  tlie  urine  of  dogs  i>ois()ned  witli  phosphorus  (Honuzynkki  and 
Gottlieb).  According  to  these  experimenters  it  has  the  formula  CoIlBaNnSOa,  ,  and 
according  to  Cloetta'  C««lIn8NaoS064.  It  does  not  contain  any  loosely  combined 
sul|)hur,  and  yields  tio  t3'rosin  on  cleaveage.  It  does  not  give  either  the  xanth(jproteic 
or  tlie  biuret  reaction.  It  gives  a  faint  response  with  Millon's  reagent,  and  is  not  pre- 
ci|ntated  by  piiospliotungstic  acid;  hence  on  this  account  it  leads  to  an  error  in  tlie 
PflL'oku  and  Bouland  method  for  estimating  urea.  Its  barium  salt  is  soluble  in  water 
but  insoluble  in  alcohol,  and  serves  in  the  preparation  of  the  acid  from  the  urine.  This 
acid  is  considered  as  an  intermediate  oxidation  product  of  proteids,  and  is  similar  iu 
certain  respects  to  Maly's  peroxyprotic  acid. 

Ptomaines  and  Icucomainen  or  poisonous  substances  of  an  unknown  kind,  which  are 
often  described  as  alkaloidal  substances,  occur  in  normal  urine  (Pouchet,  Bouchakd, 
Aducco,  and  others).  Under  pathological  conditions  the  quantity  of  these  sul)stances 
may  be  increased  (Bouchakd,  Lf.pine  and  Guekin,  Vilmeks,  Gkiffiths,  Aliju,  and 
others).  "Within  the  last  few  years  the  poisoiu)US  properties  of  urine  have  been  the  sub- 
ject of  more  thorough  investigation,  especially  by  Bouchakd.  lie  found  that  the  night 
urine  is  less  poisonous  than  the  day  urine,  and  that  the  i>oisonous  constituents  of  the 
day  and  night  urines  have  not  the  same  action.  In  order  to  be  able  to  compare  the 
toxic  power  of  the  urine  under  different  conditions,  Bouchakd  determines  the  ukotoxic 
coefficient,  which  is  the  weight  of  rabbit  in  kilos  that  is  killed  by  the  quantity  of 
urine  excreted  by  one  kilo  of  the  person  experimented  upon  in  24  hours. ^ 

Baumann  and  v.  UdrAnszky  have  shown  that  ptomaines  may  occur  in  the  urine 
under  pathological  conditions.  They  demonstrated  the  presence  of  the  two  ptomaines 
discovered  and  first  isolated  by  Bkiegek — putresciue,  CiIIuNa  (tetiamethylendiamin), 
and  cadaverin,  CjIImN^  (pentamethylendiamin) — in  the  urine  of  a  patient  suffering  from 
cystinuria  and  catarrh  of  the  bladder.  Cadaverin  has  later  been  found  by  Stadthagen 
and  Briegek  iu  the  urine  in  two  cases  of  cystinuria. 

Bkiegek.  v.  UdkAnszky  and  Baumann,  and  Stadthagen*  have  shown  that  neither 
these  nor  other  diamins  occur  under  physiological  conditions.  The  occurrence  in  nor- 
mal urine  of  any  "urine  jwison"  is  denied  by  certain  investigators,  such  as  Stadtha- 
gen, Beck,  and  v.  d.  Behgh.'*  The  poisonous  action  of  the  urine,  according  to  them, 
is  due  in  part  to  the  potassium  salts  and  in  part  to  the  sum  of  the  toxicity  of  the  other 
normal  urinary  constituents  (urea,  creatiuin,  etc.),  which  have  very  little  poisonous 
action  individually.  The  same  experimenters  have  presented  very  forcible  objections  to 
Bouchard's  doctrine. 

Many  substances  have  been  observed  in  animal  urine  which  are  not  found  in  human 
urine.  To  these  belong  the  above-described  kynureuic  acid,  iirocanic  arid,  also  found 
in  dog's  urine  and  which  seems  to  stand  in  some  relationship  to  the  purin  bases  ;  dama- 
luric  acid  and  damolic  acid  (according  to  Schotten,^  probably  a  mixture  of  benzoic  acid 
with  volatile  fatty  acids),  obtained  by  the  distillation  of  cow's  urine  ;  and  lastly  lithuric 
acid,  found  iu  the  urinary  concrements  of  certain  animals. 

III.  Inorganic  Constitnents  of  Urine. 

Chlorides.  The  chlorine  occurring  in  urine  is  undoubtedly  combined 
with  the  bases  contained  in  this  excretion;  the  chief  part  is  combined*with 
sodium.  In  accordance  with  this,  the  quantity  of  chlorine  in  the  urine  is 
generally  expressed  as  NaCl. 

'  Bondzynski  and  Gottlieb,  Centralbl.  f.  d.  med.  Wissensch..  1897,  No.  33;  TOpfer, 
ibid.,  No.  41 ;  Cloetta,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  40. 

'  A  complete  bibliography  on  ptomaines  and  leucomaines  in  the  urine  is  found  in 
Huppert-Neubauer,  p.  403. 

'  Baumann  and  Udransky,  Zeitschr.  f.  physiol.  Chem.,  Bd.  13  ;  Stadthagen  and  Brie- 
ger,  Virchow's  Arch.,  Bd.  115. 

*  Stadthagen,  Zeitschr.  f.  klin.  Med.,  Bd.  15  ;  Beck,  Pflliger's  Arch.,  Bd.  71 ;  v.  d. 
Bergh,  Zeilsch.  f.  klin.  Med.,  Bd.  35. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  7. 


464  URINE. 

The  qnestion  as  to  whether  a  part  of  the  chlorine  contained  in  the  urine 
exists  as  organic  combinations,  as  considered  by  Berlioz  and  Lepinois,  is 
still  disputed.' 

The  quantity  of  chlorine  combinations  in  the  urine  is  subject  to  con- 
siderable variation.  In  general  the  quantity  for  a  healthy  adult  on  a  mixed 
diet  is  10-15  grms.  NaCl  per  24  hours.  The  quantity  of  common  salt  in 
the  urine  depends  chiefly  upon  the  quantity  of  salt  in  the  food,  with  which 
the  elimination  of  chlorine  increases  and  decreases.  The  free  drinking  of 
water  also  increases  the  elimination  of  chlorine,  which  is  greater  during 
activity  than  during  rest  (at  night).  Certain  organic  chlorine  combina- 
tions, such  as  chloroform,  may  increase  the  elimination  of  inorganic 
chlorides  by  the  urine  (Zeller,  Kast  '). 

In  diarrhoea,  in  quick  formation  of  large  transudations  and  exudations, 
also  in  specially  marked  cases  of  acute  febrile  diseases  at  the  time  of  the 
crisis,  the  elimination  of  common  salt  is  materially  decreased.  The 
elimination  is  abnormally  increased  in  the  first  days  after  the  crisis  and 
during  the  absorption  of  extensive  exudations.  A  diminished  elimination 
of  chlorine  is  found  in  disturbed  absorption  in  the  stomach  and  intestine  in 
anaemia,  where,  according  to  Moraczewski,'  a  chlorine  retention  in  the 
blooxi  takes  place,  and  in  acute  and  chronic  diseases  of  the  kidneys  accom- 
panied with  albuminuria.  In  chronic  diseases  the  elimination  of  chlorine 
in  general  keeps  pace  with  the  nutritive  condition  of  the  body  and  the 
activity  of  the  excretion  of  the  urine.  As  under  physiological  conditions 
the  quantity  of  common  salt  taken  with  the  food  has  the  greatest  influence 
on  the  elimination  of  ISTaCl  in  disease. 

The  quantitative  estimation  of  chlorine  in  urine  is  most  simply  per- 
formed by  titration  with  silver-nitrate  solution.  The  urine  must  not 
contain  either  proteid  (which  if  present  must  be  removed  by  coagulation) 
or  iodine  or  bromine  compounds. 

In  the  presence  of  bromides  or  iodides  evaporate  a  measured  quantity  of  the  urine 
to  drjaiess,  fuse  the  residue  witli  saltpetre  and  soda,  dissolve  the  fused  mass  in  water, 
and  remove  the  iodine  or  bromine  by  the  addition  of  dilute  sulphuric  acid  and  some 
nitrite,  and  liioroughly  shake  with  carbon  disulphide.  The  liquid  thus  obtained  may 
now  I)e  titrated  with  silver  nitrate  according  to  Volhard's  method.  The  quantity  of 
bromide  or  iodide  is  calculated  as  the  diflfereuce  between  the  quantity  of  silver-nil  rate 
solution  used  for  the  titration  of  the  solution  of  the  fused  mass  and  the  quantity  used 
for  the  corresponding  volume  of  the  original  urine. 

The  otherwise  excellent  titration  method  of  Mohr,  according  to  which 
we  titrate  with  silver  nitrate  in  neutral  liquids,  using  neutral  potassium 
cliromate  as  an  indicator,  cannot  be  used'directly  on  the  urine  in  careful 
work.  Organic  urinary  constituents  are  also  precipitated  by  the  silver  salt, 
and  the  results  are  therefore  somewhat  high  for  the  chlorine.    If  we  wish  to 


'  Berlioz  and  Lepinois,  see  Chem.  Centralbl.,  1894  ;  Bd.  1,  and  1895,  Bd.  1  ;   also 
Petit  and  Terrat,  ibid,  1894,  Bd.  2,  and  Vitali,  ibid.,  1897,  Bd.  3. 
'  Zeller.  Zeitschr.  f.  physiol.  Chem.,  Bd.  8;  Kast,  ibid.,  Bd.  11. 
»  Virchow's  Arch.,  Bdd.  189  and  146. 


ESTIMATION  OF  CHLORIDES.  405 

use  this  method,  tlie  organic  urinary  constituents  must  first  be  destroyer]. 
l^"'or  this  purpose  evaporate  to  dryness  5-10  c.c.  of  the  urine,  after  the 
addition  of  1  grm.  of  chlorine-free  soda  and  1-2  grms.  chlorine-free  salt- 
petre, and  carefully  fuse.  The  mass  is  dissolved  in  water,  acidified  faintly 
with  nitric  acid,  and  then  neutralized  exactly  with  pure  lime  carbonate. 
This  neutral  solution  is  used  for  the  titration. 

The  silver-nitrate  solution  may  be  a  '— -  solution.     It  is  often  made  of 

•^  10 

such  a  strength  that  each  c.c.  corresponds  to  O.OOG  grm.  CI  or  O.Oi  grm. 

NaCl,      This  last-mentioned   solution   contains   29.075   grms.   AgNO,   in 

1  litre. 

FuEUND  and  Toepfer,  as  well  as  Bodtker,'  have  suggested  modifica- 
tions of  Moiir's  metliod. 

Voliiard's  Method.  Instead  of  the  preceding  determination,  Vol- 
HARd's  metliod,  which  can  be  performed  directly  on  the  urine,  may  be 
employed.  The  principle  is  as  follows:  All  tlie  chlorine  from  the  urine 
acidified  with  nitric  acid  is  precipitated  by  an  excess  of  silver  nitrate, 
filtered,  and  in  a  measured  part  of  the  filtrate  the  quantity  of  silver  added 
in  excess  is  determined  by  means  of  a  sulphocyanide  solution.  This  excess 
of  silver  is  completely  precipitated  by  the  sulphocyanide,  and  a  solution  of 
some  ferric  salt,  which,  as  is  well  known,  gives  a  blood-red  reaction  with 
the  smallest  quantity  of  sulphocyanide,  is  used  as  an  indicator. 

"We  rer|uire  the  following  solutions  for  this  titration:  1.  A  silver-nitrate 
solution  which  contains  29.075  grms.  AgN03  per  litre  and  of  which  each 
c.c.  corresponds  to  0.01  grm.  NaCl  or  0.00G07  grm,  CI;  2.  A  saturated 
solution  at  the  ordinary  temperature  of  chlorine-free  iron  alum  or  ferric 
sulphate;  3,  Chlorine-free  nitric  acid  of  a  specific  gravity  of  1.2;  4.  A 
potassium-sulphocyauide  solution  which  contains  8.3  grms.  KCNS  per  litre, 
and  of  which  2  c.c.  corresponds  to  1  c.c.  of  the  silver-nitrate  solution. 

About  9  grms.  of  potassium  sulphocyanide  are  dissolved  in  water  and  diluted  to 
one  litre.  The  quantity  of  KCNS  contained  in  this  solution  is  determined  by  the  silver- 
nitrate  solution  in  the  following  way  :  Measure  exaetly  10  c.  c.  of  the  silver  solution  and 
treat  with  5  c.  c.  of  nitric  acid  and  1-2  c.  c.  of  the  ferric-salt  solution,  and  diluie  with 
water  to  about  100  c.  c.  Now  the  sulpiiocyanide  solution  is  added  from  a  burette,  con- 
stantly stirring,  until  a  permanent  faint  red  coloration  of  the  liquid  takes  place.  The 
quantity  of  sulphocyanide  found  in  the  solution  by  this  means  indicates  how  much  it 
must  be  diluted  to  be  of  the  proper  strength.  Titrate  once  more  with  10  c.  c.  AgNOa 
solution  and  correct  the  sulphocyanide  solution  by  the  careful  addition  of  water  until 
20  c.  c.  exactly  corresponds  to  10  c.  c.  of  the  silver  solution. 

The  determination  of  the  chlorine  in  the  urine  is  performed  by  this 
method  in  the  following  way:  Exactly  10  c.c.  of  the  urine  is  placed  in  a 
flask  which  has  a  mark  corresponding  to  100  c.c;  o  c.c.  nitric  acid  is 
added;  dilute  with  about  50  c.c.  water,  and  then  allow  exactly  20  c.c,  of 
the  silver-nitrate  solution  to  flow  in.  Close  the  flask  with  the  thumb  and 
shake  well,  slide  off  the  thumb  and  wash  it  with  distilled  water  into  the 
flask,  and  fill  the  flask  to  the  100-c.c.  mark  with  distilled  water.  Close 
again  with  the  thumb,  carefully  mix  by  shaking,  and  filter  through  a  dry 
filter.  Measure  off  50  c.c.  of  the  filtrate  by  means  of  a  dry  pipette,  add 
3  c.c.  ferric-salt  solution,  and  allow  the  sulphocyanide  solution  to  flow  in 

'  Freund  and  Toepfer,  see  Maly's  Jahresber.,  Bd.  22  ;  BOdtker,  Zeitschr.  f.  pbysiol. 
Chem.,Bd.  20. 


466  URINE. 

■until  the  liqnid  above  the  precipitate  has  a  permanent  red  color.  The  cal- 
culation is  very  simple.  For  example,  if  4.6  c.c.  of  the  snlphocyanide 
solution  was  necessary  to  produce  the  final  reaction,  then  for  100  c.c.  of 
the  filtrate  (=  10  c.c.  urine)  9.2  c.c.  of  this  solution  is  necessary. 
9.2  c.c.  of  the  snlphocyanide  solution  corresponds  to  4.6  cc.  of  the  silver 
solution,  and  since  20  —  4.6  =  15.4  c.c.  of  the  silver  solution  was  neces- 
sary to  completely  ^precipitate  the  chlorides  in  10  c.c,  of  the  urine,  then 
10  c.c.  contains  0.154  grm.  NaCl.  The  quantity  of  sodium  chloride  in  the 
urine  is  therefore  1.54^  or  15.4  "/oo-  If  we  always  use  10  c.c.  for  the 
determination,  and  always  20  c.c.  AgNOg ,  and  dilute  with  water  to  100 
c.c,  we  find  the  quantity  of  NaCl  in  1000  parts  of  the  urine  by  subtracting 
the  number  of  c.c.  of  snlphocyanide  (E)  required  with  50  c.c.  of  the  filtrate 
from  20.     The  quantity  of  NaCl  p.  m.  is  therefore  under  these  circum- 

stances  =  20  —  E,  and  the  percentage  of  NaCl  =  — — r — . 

The  approximate  estimation  of  chlorine  in  the  urine  (which  must  be 
free  from  proteid)  is  made  by  strongly  acidifying  with  nitric  acid  and  then 
adding  to  it,  drop  by  drop,  a  concentrated  silver-nitrate  solution  (1  :  8). 
In  a  normal  quantity  of  chlorides  the  drop  sinks  to  the  bottom  as  a  rather 
compact  cheesy  lump.  In  diminished  quantities  of  chlorides  the  precipitate 
is  less  compact  and  coherent,  and  in  the  presence  of  very  little  chlorine  a 
fine  white  precipitate  or  only  a  cloudiness  or  opalescence  is  obtained. 

Phosphates.  Phosphoric  acid  occurs  in  acid  urines  partly  as  double-acid, 
MIIjPO^ ,  and  partly  as  simple-acid,  M,nPO^ ,  phosphates,  both  of  whicK 
may  be  found  in  acid  urines  at  the  same  time.  Ott  '  found  that  on  an 
average  60^  of  the  total  phosphoric  acid  was  double-  and  40^  was  simple- 
acid  phosphate.  The  total  quantity  of  phosphoric  acid  is  very  variable  and 
depends  on  the  kind  and  the  quantity  of  food.  The  average  quantity  of 
P,Oj  is  in  round  numbers  2.5  grms.,  with  a  variation  of  1-5  grms.,  per 
day.  A  small  part  of  the  phosphoric  acid  of  the  urine  originates  from 
the  burning  of  organic  compounds,  nuclein,  protagon,  and  lecithin,  within 
the  organism;  on  exclusive  feeding  with  substances  rich  in  nuclein  or 
pseudonuclein  the  quantity  of  phosphates  is  essentially  increased.'  The 
greater  part  originates  from  the  phosphates  of  the  food,  and  the  quantity  of 
eliminated  phosphoric  acid  is  greater  when  the  food  is  rich  in  alkali  phos- 
phates in  proportion  to  the  quantity  of  lime  and  magnesia  phosphates.  If 
the  food  contains  much  lime  and  magnesia,  large  quantities  of  earthy  phos- 
phates are  eliminated  by  the  excrement;  and  even  though  the  food  contains 
considerable  amounts  of  phosphoric  acid  in  these  cases,  the  quantity  of 
phosphoric  acid  in  the  urine  is  small.  Such  a  condition  is  found  in 
herbivora,  whose  urine  is  habitually  poor  in  phosphates.  The  extent  of  the 
elimination  of  phosphoric  acid  by  the  urine  depends  not  only  upon  the  total 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 

"  See  A.  Guinlicli,  Zeitsclir.  f.  pliysiol.  Clieni.,  Bd.  18;  Koos,  tbid.,  Bd.  21  ;  Wein- 
traud,  Du  Bois-Kcymond's  Arch.,  1895;  Milroy  and  Malcolm,  Journ.  of  Physiol.,  Vol. 
23;  ROhmann  and  Steinilz,  Pfltiger's  ArcL.,  Bd.  72. 


PIIOSPUA  TES.  407 

quantity  of  phosphoric  acid  in  the  food,  but  also  upon  tlie  relative  amounts 
of  alkaline  earths  and  the  alkali  salts  in  the  food.  According  to  Preysz, 
Olsavszky,  Klug,  and  I.  Ml'NK  '  tlie  elimination  of  phosphoric  acid  is 
considerably  increased  by  intense  muscular  work. 

Ab  the  extent  of  the  elimination  of  phosplioric  acid  is  mostly  dependent 
upon  tlie  character  of  the  food  and  the  absorption  of  the  pliosphates  in  tlie 
intestine,  it  is  apparent  that  the  relationship  between  the  nitrogen  and 
the  phosphoric  acid  in  the  urine  can  only  be  approximately  constant  with 
a  certain  uniform  food.  Thus  on  feeding  with  an  exclusively  meat  diet,  as 
observed  by  Voit^  in  dogs,  when  the  nitrogen  and  phosphoric  acid  (P^OJ 
of  the  food  exactly  reappeared  in  the  urine  and  fasces  the  relationship  was 
8.1  :  1.  In  starvation  this  relationship  is  changed,  namely,  relatively  more 
phosphoric  acid  is  eliminated,  which  seems  to  indicate  that  besides  flesh  and 
related  tissues  another  tissue  rich  in  phosphorus  is  largely  destroyed.  The 
starvation  experiments  show  that  this  is  the  bone-tissue. 

Little  is  known  positively  in  regard  to  the  elimination  of  phosphoric 
acid  in  disease.  As  shown  by  several  observers,  in  febrile  diseases  the 
quantity  of  phosphoric  acid  as  compared  with  the  nitrogen  is  considerably 
decreased,  which  is  perhaps  due  to  a  retention  of  the  phosphates  in  fevers.' 
In  diseases  of  the  kidneys  the  activity  of  these  organs  in  eliminating  the 
phosphates  may  be  considerably  diminished  (Fleischer*).  The  quantity 
of  phosphoric  acid  eliminated  is  increased  in  meningitis,  diabetes  mellitus, 
in  increased  destruction  of  tissues  rich  in  nuclein,  also  in  acute  pliospliorus- 
poisoning  and  in  phospJiate  diabetes.  The  statements  in  regard  to  the 
quantity  of  pliosphate  in  the  urine  in  rachitis  and  in  osteomalacia  are  some- 
what contradictory. 

Quantitative  Estimation  of  the  Total  Phosphoric  Acid  in  the  Urine.  This 
estimation  is  most  simply  performed  by  titrating  with  a  solution  of  uranium 
acetate.  The  principle  of  the  titration  is  as  follows:  A  warm  solution  of 
phosphates  containing  free  acetic  acid  gives  a  whitish-yellow  precipitate  of 
uranium  phosphate  with  a  solution  of  a  uranium  salt.  This  precipitate  is 
insoluble  in  acetic  acid,  but  dissolves  in  mineral  acids,  and  on  this  account 
there  is  always  added,  in  titrating,  a  certain  quantity  of  sodium-acetate  solu- 
tion. Potassium  ferrocyanide  is  used  as  the  indicator,  which  does  not  act  on 
the  uranium-phosphate  precipitate,  but  gives  a  reddish-brown  precipitate  or 
coloration  in  the  presence  of  the  smallest  amount  of  soluble  uranium  salt. 
The  solutions  necessary  for  the  titration  are:  1.  A  solution  of  a  uranium 
salt  of  which  each  c.c.  corresponds  to  0.005  grm.  I\0^  and  which  contains 
20.3  grms.  uranium  oxide  per  litre.     20  c.c.  of  this  solution  corresponds  to 

'  Preysz,  see  Maly's  Jahresber.,  Bd.  21  ;  Olsavszky  and  King,  Plliiger's  Arch.,  Bd. 
54  ;  Muiik,  Du  Bois-Reymond's  Arch.,  1895. 

-  Physiologic  des  allgemeiuen  Stoffwechsels  und  der  Erniihrung  in  L.  Hermann's 
Haudbuch,  Bd.  6.  Thl.  1.  S.  79. 

^  See  RemPicci  and  Beruasconi,  Maly's  Jahresber.,  Bd.  2-1,  S.  574. 

*  Dcutsch.  Arch.  f.  liliu.  Med.,  Bd.  29. 


468  UEINE. 

0.100  grni.  P^Oj.     2.  A  solution  of  sodinm  acetate.    3.  A  freshly  prepared 
solntion  of  potassinm  ferrocyanide. 

The  uranium  solution  is  prepared  from  uranium  nitrate  or  acetate.  Dissolve  about 
35  grms.  uranium  acetate  in  "n'ater,  add  some  acetic  acid  to  facilitate  solution,  and  dilute 
to  one  litre.  The  strength  of  this  solution  is  determined  l)y  titrating  with  a  solution  of 
sodium  phosphate  of  known  strength  (10.085  grms.  crystallized  salt  in  1  litre,  which  cor- 
responds to  0.100  grm.  P.jOs  in  50  c.  c).  Proceed  in  the  same  way  as  in  the  titration  of 
the  urine  (see  below),  and  correct  the  solution  by  diluting  with  water,  and  titrate  again 
until  20  c.  c.  of  the  uranium  solution  corresponds  exactly  to  50  c.  c.  of  the  above  phos- 
phate solution. 

The  sodium-acetate  solution  should  contain  10  grms.  sodium  acetate  and  10  grms. 
cone,  acetic  acid  in  100  c.  c.  For  each  titration  5  c.  c.  of  this  solution  is  used  with  50 
c.  c.  of  the  urine. 

In  performing  the  titration,  mix  50  c.c.  of  filtered  urine  in  a  beaker 
with  5  c.c.  of  the  sodinm  acetate,  cover  the  beaker  with  a  watch-glass,  and. 
warm  over  the  water-bath.  Then  allow  the  uraninm  solution  to  flow  in 
from  a  burette,  and,  when  the  precipitate  does  not  seem  to  increase,  place 
a  drop  of  the  mixture  on  a  porcelain  plate  with  a  drop  of  the  potassium- 
ferrocyanide  solntion.  If  the  amount  of  uranium  solution  employed  is  not 
sufficient,  the  color  remains  pale  yellow  and  more  uranium  solntion  must  be 
added;  but  as  soon  as  the  slightest  excess  of  uraninm  solution  has  been 
used  the  color  becomes  faint  reddish  brown.  When  this  point  has  been 
obtained,  warm  the  solntion  again  and  add  another  drop.  If  the  color 
remains  of  the  same  intensity,  the  titration  is  ended;  but  if  the  color  varies, 
add  more  uranium  solution,  drop  by  drop,  until  a  permanent  coloration  is 
obtained  after  warming,  and  now  repeat  the  test  with  another  50  c.c.  of  the 
urine.  The  calculation  is  so  simple  that  it  is  unnecessary  to  give  an 
example. 

In  the  above  manner  we  determine  the  total  quantity  of  phosphoric  acid 
in  the  urine.  If  we  wish  to  know  the  phosphoric  acid  combined  with 
alkaline  earths  or  with  alkalies,  Ave  first  determine  the  total  phosphoric  acid 
in  a  portion  of  the  urine  and  then  remove  the  earthy  phosphates  in  another 
portion  by  ammonia.  The  precipitate  is  collected  on  a  filter,  washed, 
transferred  in  a  beaker  with  water,  treated  with  acetic  acid,  and  dissolved 
by  warming.  This  solution  is  now  diluted  to  50  c.c.  with  water,  and  5  c.c. 
sodium-acetate  solution  added,  and  titrated  with  uraninm  solntion.  The 
difference  between  the  two  determinations  gives  the  quantity  of  phosphoric 
acid  combined  with  the  alkalies.  The  results  obtained  are  not  quite 
accurate,  as  a  partial  transformation  of  the  monophosphates  of  the  alkaline 
earths  and  also  calcium  diphosphate  into  triphosphates  of  the  alkaline  earths 
and  ammonium  phosphate  takes  place  on  precipitating  with  ammonia, 
which  gives  too  high  results  for  the  phosphoric  acid,  combined  with  alkalies 
remaining  in  solution. 

Determination  of  Acidity  of  the  Urine.  '  As  previously  remarked,  we 
consider  the  quantity  of  phosphoric  acid  as  double-acid  salts  as  a  measure 
of  the  degree  of  acidity  of  the  urine.  This  may  be  determined  by  titrating 
■with  uranium  solntion  in  theliitrate  after  the  precipitation  of  the  mono- 
acid  salts  by  barium  chloride.  If  the  total  phosplioric  acid  has  been  deter- 
mined in  another  portion  of  the  urine  by  titration,  the  quantity  of  phos- 
phoric acid  as  mono-acid  phosphates  is  found  in  the  difference  between  these 


SULPHATES.  469 

two  results.     Tlie  iletermiiiation  is  performed,  according  to  Fuel'nd  and 
JjIKHLEIn,'  as  follows: 

Tlie  total  phosphoric  acid  is  first  determined  in  the  urine.  Then 
75  CO.  of  the  urine  is  treated  witii  enougii  normal  barium-chloride  solu- 
tion (122  grm.  Bad, ,211,0  in  1000  c.c.  water)  to  nuike  the  volume  measure 
90  c.c.  This  is  shaken,  filtered  until  a  clear  filtrate  \a  obtained  when  GO  c.c. 
(=50  c.c.  of  the  urine)  is  measured  oil  and  the  i)hosplioric  acid  deter- 
mined by  uranium  solution.  The  results  are  not  quite  exact,  as  in  the 
precipitation  of  tlie  urine  with  liaCl,  about  3^  of  the  phosphoric  acid  of  the 
mono-acid  salts  remain  in  solution  as  di-acid  salts,  and  hence  a  correspond- 
ing correction  must  be  made.  As  one  third  of  the  phosphoric  acid  of  the 
di-acid  phosphate  is  united  with  fixed  bases,  Lieblein  is  of  the  opinion 
that  in  calculating  the  acidity  of  a  urine  only  two  thirds  of  this  phosphoric 
acid  is  to  be  ascribed  thereto.  Other  methods  have  been  suggested  by 
Fkeun'I)  and  Toepfeu  and  v.  Jager. 

Sulphates.  The  sulphuric  acid  of  the  urine  originates  oSiy  to  a  very 
small  extent  from  the  sulphates  of  the  food.  A  disproportionately  greater 
part  is  formed  by  the  burning  of  the  proteids  containing  sulphur  within 
the  body,  and  it  is  chiefly  this  formation  of  sulphuric  acid  from  the  proteids 
which  gives  rise  to  the  previously  mentioned  excess  of  acids  over  the  bases 
in  the  urine.  The  quantity  of  sulphuric  acid  eliminated  by  the  urine 
amounts  to  about  2.5  grms.  11,80^  per  day.  As  the  sulphuric  acid 
chiefly  originates  from  the  proteids,  it  follows  that  the  elimination  of  sul- 
phuric acid  and  the  elimination  of  nitrogeu  are  nearly  parallel,  and  the 
relationship  N  :  11,80^  is  about  5:1.  A  complete  parallelism  can  hardly 
bo  expected,  as  in  the  first  place  a  part  of  the  sulphur  is  always  eliminated 
as  neutral  sulphur,  and  secondly  because  the  small  proportion  of  sulphur  in 
different  protein  bodies  undergoes  greater  variation  as  compared  with  the 
large  proportion  of  nitrogen  contained  therein.  In  general  the  relationsliip 
between  the  elimination  of  nitrogen  and  sulphuric  acid  under  normal  and 
under  diseased  conditions  runs  rather  parallel.  Sulphuric  acid  occurs  in  the 
urine  partly  preformed  (sulphate-sulphuric  acid)  and  partly  as  ethereal- 
sulphuric  acid.  The  first  is  designated  as  A-  and  the  other  as  ^-sulphuric 
acid. 

The  qtianiity  of  total  sulplniric  acid  is  determined  in  the  following  way, 
but  at  the  same  time  the  precautions  described  in  other  works  must  be 
observed:  100  c.c.  of  filtered  urine  is  treated  with  5  c.c.  concentrated 
hydrochloric  acid  and  boiled  for  fifteen  minutes.  While  boiling  ])recipitate 
with  2  c.c.  of  a  saturated  BaCl,  solution,  and  warm  for  a  little  while  until 
the  barium  sulphate  has  completely  settled.  The  precipitate  must  then  be 
washed  with  water  and  also  with  alcohol  and  ether  (to  remove  resinous 
substances),  and  then  treated  according  to  the  usual  method. 

The  separate  determination  of  the  sulphate-sul])huric  acid  and  the 
ethereal-sulphuric  acid  may  be   accomplished,   according   to  Baumann's 


•  Freuiul,    Ceiitralbl.    f.    d.    med.    Wisseusch.,  1893,  S.  689;  Liebleiu,  Zeitschr.  f. 
physiol.  Chem.,  Bd.  20;  Freund  aud  Toepfer,  ibid.,  Bd.  19  ;  de  Jager,  ibid.,  Bd.  24. 


470  URINE. 

method,  by  first  precipitating  the  snlphate-snlphnric  acid  from  the  urine 
acidified  with  acetic  acid  by  BaCl^,  then  decomposing  the  ethereal- 
sulphnric  acid  by  boiling  after  the  addition  of  hydrochloric  acid,  and  then 
determining  the  sulphuric  acid  set  free  as  barium  sulphate.  A  still  better 
method  is  the  following,  suggested  by  Salkowski  ' : 

200  c.c.  of  urine  is  precipitated  by  an  equal  volume  of  a  barium  solution 
which  consists  of  3  yoIs.  barium  hydrate  and  1  vol.  barium-chloride  solu- 
tion, both  saturated  at  the  ordinary  temperature.  Filter  through  a  dry 
filter,  measure  off  100  c.c.  of  the  filtrate  which  contains  only  the  ethereal- 
snlphnric  acid,  treat  with  10  c.c.  hydrochloric  acid  of  a  specific  gravity 
1.12,  boil  for  fifteen  minutes,  and  then  warm  on  the  water-bath  until  the 
precipitate  has  completely  settled  and  the  supernatant  liquid  is  entirely 
clear.  Filter  and  wash  with  warm  water,  and  with  alcohol  and  ether,  and 
proceed  according  to  the  generally  prescribed  method.  The  difference 
between  the  ethereal-sulphuric  acid  found  and  the  total  quantity  of  sulphuric 
acid  as  determined  in  a  special  portion  of  urine  is  taken  to  be  the  quantity 
of  sulphate-sulphuric  acid. 

Nitrates  occur  in  small  quautities  in  human  urine  (Schonbein),  and  they  probably 
originate  from  the  drinking-water  and  the  food.  According  to  Weyl  and  Citron''  the 
quantity  of  nitrates  is  smallest  with  a  meat  diet  and  greatest  with  vegetable  food.  The 
average  amount  is  about  42.5  milligrammes  per  litre. 

Potassium  and  Sodium.  The  quantity  of  these  bodies  eliminated  by  the 
nrinfe  by  a  healthy  full-grown  person  on  a  mixed  diet  is,  according  to 
Saxkowski,^  3-4  grms.  K^O  and  5-8  grms.  Na^O,  with  an  average  of 
about  2-3  grms.  K,0  and  4-6  grms.  Na^O.  The  proportion  of  K  to  Na  is 
ordinarily  as  3  :  5.  The  quantity  depends  above  all  upon  the  food.  In 
starvation  the  urine  may  become  richer  in  potassium  than  in  sodium,  which 
results  from  the  lack  of  common  salt  and  the  destruction  of  tissue  rich  in 
potassium.  Tlie  quantity  of  potassium  may  be  relatively  increased  during 
fever,  while  after  the  crisis  the  reverse  is  the  case. 

The  quantitative  estimation  of  these  bodies  is  performed  by  the  gravi- 
metric methods  as  described  in  works  on  quantitative  analysis. 

Ammonia.  Some  ammonia  is  habitually  found  in  human  urine  and  in 
tliat  of  carnivora.  As  above  stated  (page  413),  this  ammonia  may  repre- 
sent, on  the  formation  of  urea  from  ammonia,  the  small  amount  of 
ammonia  which,  because  of  the  excess  of  acids  formed  by  the  combustion, 
as  compared  with  the  fixed  alkalies,  is  united  with  such  acids,  and  in  this 
way  is  excluded  from  the  synthesis  to  urea.  This  view  is  confirmed  by  the 
observations  of  Coranda,  who  found  that  the  elimination  of  ammonia  was 
smaller  on  a  vegetable  diet  and  larger  on  a  rich  meat  diet  than  on  a 
mixed  diet.  On  a  mixed  diet  the  average  amount  of  ammonia  eliminated 
by    the    urine   is  about   0.7   grm.    Nil,   per   day    (Neubauer).     All  the 

'  Baiiinann,  Zeitschr.  f.  physiol.  Cliem.,  Bd.  1  ;  Salkowski,  Virchow's  Arch.,  Bd.  79. 
'  Scli5nbi,'iii,  .Tourn.  f.  prakt.  Chera.,  Bd.  92  ;  Weyl,  Virchow's  Arch.,  Bd.  96,  with 
Citron,  ibid.,  Bd.  101. 
^  Ibid.,  Bd.  53. 


AMMONIA.  471 

ammonia  of  the  nrine,  as  above  stated,  is  not  represented  by  the  residne 
which  has  ehided  synthesis  into  urea  by  neutralization  by  acids,  because,  as 
shown  by  Stadelmaxn  and  Beckmann,'  ammonia  is  eliminated  by  the 
urine  even  daring  the  continuous  administration  of  fixed  alkalies. 

Ammonia  exists  on  an  average  of  about  0.96  milligramme  in  100  c.c. 
human  blood,  and  in  diiferent  amounts  in  all  the  tissues  thus  far  investi- 
gated." According  to  Nencki  and  Zaleski'  it  is  abundantly  formed 
in  the  cells  of  the  digestive  glands,  the  stomach,  the  pancreas,  and  the 
intestinal  mucosa  (of  dogs)  at  the  time  when  proteid  foods  are  being  digested 
and  transported  to  the  liver.  As  the  ammonia  introduced  in  the  liver 
is  transformed  into  urea  (see  above),  we  can  therefore  expect  that  in 
certain  diseases  of  the  liver  an  increased  elimination  of  ammonia  and  a 
decreased  elimination  of  urea  will  occur.  In  how  far  this  is  true  has 
already  been  stated  (page  415),  and  we  refer  to  the  researches  of  the  various 
authors  there  cited. 

In  man  and  carnivora  the  elimination  of  ammonia  is  increased  by  the 
introduction  of  mineral  acids  and,  as  shown  by  Jolin,  also  by  such  organic 
acids  as  benzoic  acid,  which  are  not  destroyed  in  the  body,  act  in  a  similar 
manner.  Tiie  ammonia  set  free  in  the  proteid  destruction  is  in  part  used 
in  the  neutralization  of  the  acids  introduced,  and  in  this  way  a  destructive 
abstraction  of  fixed  alkalies  is  prevented.  Ilerbivora,  on  the  contrary,  lack 
this  property  or  have  it  only  to  a  slight  extent  (Wixterberg  *).  In  them 
the  acids  introduced  are  neutralized  by  fixed  alkalies;  hence  the  introduc- 
tion of  mineral  acids  soon  causes  a  destructive  action  on  account  of  the 
abstraction  of  alkalies. 

Acids  formed  in  the  destruction  of  proteids  in  the  body  act  like  those 
introduced  from  without  on  tiie  elimination  of  ammonia.  For  this  reason 
the  quantity  of  aniinonia  in  human  and  carnivoral  urine  is  increased  under 
such  conditions  and  in  such  diseases  where  an  increased  formation  of  acid 
takes  place  because  of  an  increased  metabolism  of  proteids.  This  is  the  case 
with  lack  of  oxygen  in  fevers  and  diabetes.  In  the  last-mentioned  disease 
organic  acids,  /i-oxybutyric  acid,  and  aceto-acetic  acid,  are  produced  wiiich 
pass  into  the  urine  combined  with  ammonia.' 

'  Coianda,  Arch.  f.  exp.  Puth.  u.  Plmrm.,  Bd.  12;  Sladelmanu  (and  Beckmaun), 
"Einfluss  der  Alkalien  auf  deu  SlolTwechsel,"  etc.     Stuttgart,  1890. 

»  See  Salaskin,  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  25,  S.  449. 

'  Arch,  des  science  biol.  de  St.  Pe;eisb<>urg,  Tonic  4,  and  Salaskin,  I.  c.  See  also 
Nencki  and  Zideski,  Arch.  f.  c.\p.  Path.  u.  Pharni.,  Bd.  37. 

*  Jolin,  Skand.  Arch.  f.  Ph\siol.,  Bd.  1  ;  Winterberg,  Zeitschr.  f.  physiol.  Chem., 
Bd.  25.  In  regard  to  the  behavior  of  amraouiuin  salts  in  the  animal  body  see  Riiinpf 
and  Kleine,  Zeitschr.  f.  Biologic,  Bd.  34,  and  the  works  cited  on  page  412. 

*  On  the  elimination  of  ammonia  in  disease  see  the  recent  works  of  Rumpf,  Virchow's 
Arch.,  Bd.  143;  Ilallervorden,  ibid. 


472  URINE. 

The  detection  and  quantitative  estimation  of  ammonia  is  performed 
generally  according  to  the  method  suggested  by  Schlosing.  The  principle 
of  this  method  is  that  the  ammonia  from  a  measured  amount  of  urine  is  set 
free  by  lime-water  in  a  closed  vessel  and  absorbed  by  a  measured  amount  of 

—  sulphuric  acid.     After  the  absorption  of  the  ammonia  the  quantity  is 

determined  by  titrating  the  remaining  free  sulphuric  acid  with  a  —  caustic 

alkali  solution.  This  method  gives  low  results,  and  in  exact  work  we  must 
proceed  as  suggested  by  Borland.  '  Other  methods  have  been  suggested  by 
ScHMiEDEBERG  and  by  Latschenberger.' 

Calcium  and  magnesium  occur  in  the  urine  for  the  most  part  as  phos- 
phates. The  quantity  of  earthy  phosphates  eliminated  daily  is  somewhat 
more  than  1  gr.,  and  of  this  amount  f  is  magnesium  and  ^  calcium  phos- 
phate. In  acid  urines  the  simple-  as  well  as  the  double-acid  earthy 
phosphates  are  found,  and  the  solubility  of  the  first,  among  which  the 
calcium  salt  CaHPO,  is  especially  insoluble,  is  particularly  aagmented  by 
the  presence  of  double-acid  alkali  phosphate  and  sodium  chloride  in  the 
urine  (Ott').  The  quantity  of  alkaline  earths  in  the  urine  depends  on  the 
composition  of  the  food.  The  absorbed  lime  salts  are  in  great  part  precipi- 
tated Again  in  the  intestine,  and  the  quantity  of  lime  salts  in  the  urine  is 
therefore  no  measure  of  the  absorption  of  the  same.  The  introduction  of 
readily  soluble  lime  salts  or  the  addition  of  hydrochloric  acid  to  the  food 
may  therefore  cause  an  increase  in  the  quantity  of  lime  in  the  urine,  while 
the  reverse  takes  place  on  adding  alkali  phosphate  to  the  food.  Nothing  is 
known  with  positiveness  in  regard  to  the  constant  and  regular  change  in 
the  elimination  of  calcium  and  magnesium  salts  in  disease.  The  increased 
elimination  observed  in  diabetes  is  chiefly  dependent  upon  an  increased 
consumption  of  food  and  liquids  (Tenbaum  *). 

The  quantity  of  calcium  and  magnesium  is  determined  according  to  the 

ordinary  well-known  methods. 

Iron  occurs  in  the  urine  only  in  small  quantities,  and,  as  it  seems  from  the  investiga- 
tions of  KuNKEL,  GiACOSA,  KoBERT  and  his  pupils,  it  does  not  exist  as  a  salt,  but  as  an 
organic  combination — in  part  as  pigment  or  cliromogen.  The  statements  in  regard  to 
the  iron  present  seem  to  show  that  the  quantity  is  very  variable,  from  1  to  11  milli- 
grammes per  litre  of  urine  (Magnier,  (jtottlieb,  Robert  and  his  pupils).  Jolles* 
found  as  an  average  for  12  persons  8  milligrammes  iron  in  24  hours.     The  quantity  of 

>  PflUger's  Arch.,  Bd.  43,  S.  32. 

'  Schmiedeberg,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  7  ;  Latschenberger,  Monats- 
hefte  f.  Chem.,  Bd.  5. 

'  Zeitschr.  f.  physio).  Chem.,  Bd.  10. 

*  Zeitschr.  f.  Biologie,  Bd.  33. 

'  Kunkel,  cited  from  Miiiy's  Jahresber.,  Bd.  11;  Giacosa,  ibid.,  Bd.  16  ;  Robert, 
Arbeiten  des  pharm.  Instit.  zu  Dorpat,  Bd.  7;  Magnier,  Ber.  d.  deutsch.  chem. 
Gesellsch.,  Bd.  7;  Gottlieb,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  26  ;  Jollcs,  Zeitschr.  f. 
anal.  Chem..  Bd.  36. 


QUANTITATIVE  COMPOSITION  OF  UlilNE.  473 

$ilicic  acid  is  ordinarily  stated  to  amount  to  about  0.03  p.  m.     Traces  oi  hydrogen  per- 
oxide also  occur  in  tlie  urine. 

The  gases  of  tlie  tiriiie  are  carbon  dioxide,  nitrogen,  and  traces  of 
oxygen.  Tlie  quantity  of  nitrogen  is  not  finite  1  vol.  per  cent.  The 
carbon  dioxide  varies  considerably.  In  acid  nrines  it  is  hardly  one  half  as 
great  as  in  neutral  or  alkaline  urines. 

IV.  The  Quantity  and  Quantitative  Composition  of 

Urine. 

A  direct  participation  of  the  kidney  substance  in  the  formation  of  the 
urinary  constituents  is  proved  at  least  for  one  constituent  of  the  urine, 
namely,  hippuric  acid.  It  is  hardly  to  be  doubted  that  the  kidneys  as  well 
as  the  tissues  generally  have  a  certain  part  to  play  in  the  formation  of  other 
iirinary  constituents,  but  their  chief  task  consists  in  sejiarating  and  remov- 
ing urinary  constituents  dissolved  in  the  blood  which  have  been  taken  up 
by  it  from  other  organs  and  tissues. 

It  has  been  shown  by  the  experiments  of  numerous  investigators  that 
the  elimination  of  water  and  the  remaining  urinary  constituents  is  not 
alone  produced  by  simple  diffusion  and  filtration."  It  is  generally  conceded 
that  the  urinary  excretion  is  caused  essentially  by  a  specific  activity  of 
the  cells  of  the  epithelium  of  the  urinary  passages,  the  processes  of  fil- 
tration and  diffusion  also  taking  part.  The  excretion  of  urine  in  man  and 
the  higher  animals  is  thought  to  proceed  about  as  follows:  The  water 
together  with  a  small  amount  of  the  salts  passes  through  the  glomeruli, 
while  the  chief  part  of  the  solids  is  secreted  by  the  epithelium  of  the 
urinary  passages.  A  secretion  of  solids  without  a  simultaneous  secretion 
of  water  is  not  possible,  and  therefore  a  part  of  the  water  must  be  secreted 
by  the  epithelium-cells  of  the  urinary  passages.  The  passage  of  the  greater 
part  of  tlie  water  through  the  glomeruli  is  rather  generally  considered  as  a 
filtration  due  to  blood-pressure.  According  to  Heidenhaix  the  thin  cell- 
layers  of  the  glomeruli  have  a  secretory  action. 

The  quantity  and  composition  of  urine  are  liable  to  great  variation. 
The  circumstances  which  under  physiological  conditions  exercise  a  great 
influence  are  the  following:  the  blood-pressure,  and  the  rapidity  of  the 
blood-current  in  the  glomeruli;  the  quantity  of  urinary  constituents, 
especially  water  in  the  blood;  and,  lastly,  the  condition  of  the  secretory 
glandular  elements.  Above  all,  the  quantity  and  concentration  of  the  urine 
depend  on  the  elimination  of  water.  That  this  hist  may  vary  with  the 
quantity  of  water  in  the  blood,  with  changed  blood-pressure,  and  with 
circulatory  conditions  is  evident;  but  under  ordinary  circumstances  the 
quantity  of  water  eliminated  by  the  kidneys  depends  essentially  upon  the 

'  See  text-books  of  physiology  on  this  topic. 


474  URINE. 

qaantity  of  water  which  is  brought  to  them  by  the  blood,  or  which  leaves 
the  body  by  other  exits.  The  elimination  of  urine  is  increased  by  drinking 
freely,  or  by  reducing  the  quantity  of  water  otherwise  removed;  but  it 
is  decreased  by  a  diminished  introduction  of  water,  or  by  a  greater  loss  of 
water  in  other  ways.  Ordinarily  in  man  Just  as  much  water  is  eliminated 
by  the  kidneys  as  by  the  skin,  lungs,  and  intestine  together.  At  lower  tem- 
peratures and  in  moist  air,  since  nnder  these  conditions  the  elimination  of 
water  by  the  skin  is  diminished,  the  elimination  of  urine  may  be  consider- 
ably increased.  Diminished  introduction  of  water  or  increased  elimina- 
tion of  water  by  other  means — as  in  violent  diarrhoea  or  vomiting,  or  in 
profuse  perspiration — greatly  diminishes  the  elimination  of  urine.  For 
example,  the  urine  may  sink  as  low  as  500-400  c.c.  per  day  in  intense 
summer-heat,  while  after  copious  draughts  of  water  the  elimination  of 
3000  c.c.  of  urine  has  been  observed  during  the  same  time.  The  quantity 
of  urine  voided  in  the  course  of  24  hours  varies  considerably  from  day  to 
day,  the  average  being  ordinarily  calculated  as  1500  c.c.  for  healthy  adult 
men  and  1200  c.c.  for  women.  The  minimum  elimination  occurs  during 
the  early  morning,  between  2  and  4  o'clock;  the  maximum,  in  the  first 
hours  after  waking  and  from  1-2  hours  after  a  meal. 

The  quantity  of  solids  excreted  per  day  is  nearly  constant  even 
though  the  quantity  of  urine  may  vary,  and  it  is  quite  constant  when 
the  manner  of  living  is  regular.  Therefore  the  percentage  of  solids  in 
the  urine  is  naturally  in  inverse  proportion  to  the  quantity  of  urine. 
The  average  amount  of  solids  per  24  hours  is  calculated  as  60  grms. 
The  quantity  may  be  calculated  with  approximate  accuracy  by  means  of 
the  specific  gravity  if  the  second  and  third  decimals  of  the  specific  gravity 
be  multiplied  by  Haser's  coefficient,  2.33.  The  product  gives  the 
amount  of  solids  in  1000  c.c.  of  urine,  and  if  the  quantity  of  urine 
eliminated  in  24  hours  be  measured,  the  quantity  of  solids  in  24  hours 
may  be  easily  calculated.  For  example,  1050  c.c.  of  urine  of  a  specific 
gravity   1.021    was   eliminated   in    24   hours;    therefore   the   quantity   of 

48  9  X  1050 
solids  eliminated  is  21  X  2.33  =  48.9,   and   — '  =  51.35   grms. 

The  urine  in  this  case  contained  48.9  p.  m.  solids  and  51.35  grms.  in  the 
daily  excretion. 

Those  bodies  which,  under  physiological  conditions,  affect  the  density 
of  the  urine  are  common  salt  and  urea.  The  specific  gravity  of  the  first  is 
2.15,  and  the  last  only  1.32;  so  it  is  easy  to  understand,  when  the  relative 
proportion  of  these  two  bodies  essentially  deviates  from  the  normal,  why 
the  above  calculation  from  the  specific  gravity  is  not  exact.  The  same  is 
the  case  when  a  urine  poor  in  a  normal  constituent  contains  large  amounts 
of  foreign  bodies,  such  as  albumin  or  sugar. 

As  above  stated,  the  percentage  of  solids  in  the  urine  generally  decreases 


CASUAL    URIXAHT  CONSTITUEyTS.  AIT) 

•with  a  greater  elimination,  and  a  very  considerable  excretion  of  urine 
{polyuria)  has  therefore,  as  a  rule,  a  lower  specific  gravity.  An  important 
exception  to  this  rale  is  observed  in  urine  containing  sugar  {diabetes 
mellitus),  in  svhich  there  is  a  copious  excretion  of  a  very  high  specific 
gravity  due  to  the  sugar.  In  cases  where  very  little  urine  is  excreted 
{oliguria),  e.g.,  during  profuse  perspiration,  in  diarrhoea,  and  in  fevers, 
the  specific  gravity  of  the  urine  is  as  a  rule  very  high;  the  percentage  of 
solids  also  high  and  they  have  a  dark  color.  Sometimes,  as,  for  example,  in 
certain  cases  of  albuminuria,  the  urine  may  have  a  low  specific  gravity 
notwithstanding  the  oliguria,  and  be  poor  in  solids  with  a  light  color. 

It  is  difficult  to  give  a  tabular  view  of  the'  composition  of  urine,  on 
account  of  its  variation.  For  certain  purposes  the  following  table  may  be 
of  some  value,  but  it  must  not  be  overlooked  that  the  results  are  not  given 
for  1000  parts  of  urine,  but  only  approximate  figures  for  the  quantities  cf 
the  most  important  constituents  which  are  eliminated  in  the  course  of  2-t 
hours  in  a  quantity  of  1500  c.c. 

Daily  quantity  of  solids  =  60  grms. 
Organic  constituents  =  35  gnus.  I    Inorganic  constituents  =  25  gnns. 

Urea 30.0  grms.  |        Sodium  chloriiie  (NaCl) 15.0  grms. 


Uric  acid 0.7 

Crealinin  1.0 

Hippuric  acid 0.7 

Remuiuing  organic  bodies. .  2.6 


Stilpliuric  acid  (HjSO,) 2.5 

Phosphoric  acid  (PiOs) 2.5 

Potash  (K,0)  3.3 

Ammonia  (NHj) 0.7 

M:ignesia  (MgO) 0.5 

Lirue  (CaO)  .^. 0.3 

Remaiuiui;  iuoraranic  bodies.  0.2 


Urine  contains  on  an  average  -iO  p.  m.  solids.  The  quantity  of  urea  is 
about  20  p.  m.,  and  common  salt  about  10  p.  m. 

V.  Casual  Urinary  Constituents. 

The  casual  appearance  in  the  urine  of  medicines  or  of  urinary  con- 
stituents resulting  from  the  introduction  of  foreign  substances  into  the 
organism  is  of  practical  importance,  because  such  constituents  may  interfere 
in  certain  urinary  investigations,  and  also  because  they  afford  a  good  means 
of  determining  whether  certain  substances  have  been  introduced  into  the 
organism  or  not.  From  this  point  of  view  a  few  of  these  bodies  will  be 
spoken  of  in  a  following  section  (on  the  pathological  urinary  constituenta). 
The  presence  of  these  foreign  bodies  in  the  urine  is  of  special  interest  in 
those  cases  in  which  they  serve  to  elucidate  the  chemical  transformations 
certain  substances  undergo  within  the  body.  As  inorganic  substances 
generally  leave  the  body  unchanged,  they  are  of  very  little  interest  from 
this  standpoint,  but  the  changes  which  certain  organic  substances  undergo 
when  introduced  into  the  animal  body  may  be  studied  by  this  means  so  far 
as  these  transformations  are  shown  by  the  urine. 


476  URINE. 

The  bodies  belonging  to  the  fatty  series  undergo,  though  not  without 
exceptions,  a  combustion  leading  towards  the  final  products  of  meta- 
bolism ;  still,  often  a  greater  or  smaller  part  of  the  body  in  question  escapes 
oxidation  and  appears  unchanged  in  the  urine.  A  part  of  the  acids  belong- 
ing to  this  series  which  are  otherwise  burnt  into  water  and  carbonates  and 
render  the  urine  neutral  or  alkaline  may  act  in  the  same  manner.  The 
volatile  fatty  acids  poor  in  carbon  are  less  easily  oxidized  than  those  rich  in 
carbon,  and  they  therefore  pass  unchanged  into  the  urine  in  large  amounts. 
This  is  especially  true  of  formic  and  acetic  acids  (ScHOTTEisr,  Geehant  and 
QuiXQUAUD').  The  statements  in  regard  to  oxalic  acid  are  contradictory. 
In  birds,  according  to  GAGfLio  and  Giunti,  it  is  not  oxidized.  In  mammals 
it  is  in  great  part  oxidized,  according  to  Giunti,  while  Gaglio  and  Pohl 
claim  that  it  is  indestructible.  In  human  beings  oxalic  acid  is  in  great  part 
oxidized,  according  to  Marfori  and  Giukti.  Tartaric  acid  acts  dilferenth' , 
according  to  BRiOiSr;  namely,  in  dogs  the  Isevo-tartaric  acid  is  nearly  entirely 
consumed,  while  a  little  more  than  70;^  of  dextro-tartaric  acid  is  burnt. 
Eacemic  acid  is  oxidized  to  a  still  less  extent  in  the  animal  body.  Snccinic 
and  malic  acids  are  completely  combustible,  according  to  Pohl.^ 

The  acid  amides  appear  not  to  be  changed  in  the  body  (Schultzen  and 
Nenoki').  a  small  part  of  the  amido-acids  seems  indeed  to  be  eliminated 
unchanged,  but  otherwise  they  are,  as  stated  above  (page  412)  for  leucin, 
glycocoll,  and  aspartic  acid,  decomposed  within  the  body,  and  they  may 
therefore  cause  an  increased  elimination  of  urea.  Sarcosi7i  (methylglyco- 
coll),  XH(CH3).CH2.C00H,  also  perhaps  passes  in  small  part  into  the 
corresponding  aramido-acid,  methylhydantoic  acid,  NHg.C0.N(CH3). 
Cn^.COOH  (ScHULTZEN^).  Likewise  taiirin,  amido-ethylsulphonic  acid, 
which  acts  somewhat  differently  in  different  animals  (Salkowski  ^),  passes 
in  human  beings,  at  least  in  part,  into  the  corresponding  uramido-acid, 
taurocarbamic  acid,  NH,.  CO.NH.  CJI^.SO,.  OH.  A  part  of  the  taurin  also 
appears  as  sach  in  the  urine.  In  rabbits,  when  taurin  is  introduced  into 
the  stomach  nearly  all  its  sulphur  aj^pears  in  the  urine  as  sulphuric  and 
hyposulphurous  acids.  After  subcutaneous  injection  the  taurin  appears 
again  in  great  part  unchanged  in  the  iirine. 

'  Schotleu,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  7;  Grehaut  aud  Quinquaud,  Compt. 
rend.,  Tome  104. 

'  Gaglio,  Arcb.  f.  exp.  Path.  u.  Pharm.,  Bd.  23  ;  Giuuti,  Chem.  Centrnlbl.,  1897, 
Bd.  2  ;  Marfori,  Maly's  Jabresber.,  Bd.  20  ;  Briou,  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  25; 
Polil,  Arcb.  f.  exp.  Path.  u.  Pharm.,  Bd.  37,  where  a  statement  as  to  the  intermediate 
products  of  the  oxidatiou  of  fatty  bodies  may  be  found. 

»  Zeitschr.  f.  Biologic,  Bd.  8. 

*  Bcr.  d.  deutsch.  chem.  Gesellscb.,  Bd.  5.  See  also  Baumann  aud  v.  Mering,  ibid., 
Bd.  8,  S.  584,  aud  E.  Salkowski,  Zeitschr.  f.  pbysiol.  Chem.,  i3d.  4,  S.  107. 

'  Ber.  d.  deutsch.  chem.  Gesellscb.,  Bd.  6,  aud  Virchow's  Arch.,  Bd.  58. 


CASUAL   CONSTITUENTS.  477 

The  nitrihs,  including  hydrocyanic  acid,  pass,  according  to  Lang,  into 
anlphocyanide  combinations,  and  this  sulphocyanide  seems  to  originate  from 
the  non-oxidized  sulphur  of  tlie  proteids,  whicli  is  readily  split  off.  This 
snlphnr  can,  according  to  Pasciieles'  '  observations,  convert  the  cyan 
alkalies  readily  into  snlphocyanides  in  alkaline  reaction  and  at  the  tempera- 
ture of  the  body. 

By  siihsiitution  with  halogens  otherwise  readily  oxidizable  bodies  are 
converted  into  difficultly  oxidizable  ones.  "While  the  aldeliydes  are  readily 
and  completely  burnt  like  the  primary  and  secondary  alcohols  of  the  fatty 
series,  the  halogen  substituted  aldehydes  and  alcohols  are,  on  the  contrary, 
difficultly  oxidizable.  The  halogen  substitution  products  of  methane 
(chloroform,  iodoform,  and  bromoform)  are  at  least  in  part  burnt,  and  th^ 
corresponding  alkali  combination  of  the  halogen  jiasses  into  the  urine.' 

By  coupling  with  stdpMiric  acid  the  otherwise  readily  oxidizable  Jc-.cohola 
may  be  guarded  against  combustion,  and  correspondingly  the  ah-tali  salt  of 
ethylsulphuric  acid  is  not  burnt  in  the  body  (Salkowski'). 

The  07-ganic  comhinations  C07itaining  snlphnr  act  somewhat  differently. 
According  to  W.  Smith  the  sulphur  of  the  thio  acids  like  thioglycolic  acid, 
CIIj.SII.COOII,  is  in  part  oxidized  to  sulphuric  acid,  and  according  to 
GoLDMANX  amidothiolactic  acid  (cystein)  and  the  sulphur  of  the  thio 
alcohols  (ethyl  mercaptans)  are  also  oxidized  into  sulphuric  acid.  On  the 
contrary,  ethylsulphide,  sulphonic  and  sulpho  acids  in  general  (Salkowski, 
Smith  ')  are  not  oxidized  into  snlphuric  acid.  Oxyethylsnlphonic  acid, 
HO.C,n^.SO,.On,  which  is  in  part  oxidized  to  sulphuric  acid,  is  an 
exception  (Salkowski). 

Conjngation  with glgcnroiic  acid  occurs  in  certain  substituted  alcohols, 
aldehydes,  and  ketones  (?),  which  probably  first  pass  over  into  alcohols 
(Suxdvik).  Cliloral  hydrate,  C,C1,0II  +  H,0,  passes,  after  it  has  been 
converted  into  trichlorethyl-alcohol  by  a  reduction,  into  a  Isevogyrate  reduc- 
ing acid,  urochhraJic  acid  or  trichlorethyl-glycuronic  acid,  C^CljH^.CjIIjO, 
(MuscuLUS  and  v.  Mering').  TrichlorhntyJ- alcohol  and  hutyl-chloral 
hydrate  also  pass  into  trichlorhctyl-glycuronic  acid. 


'  Lang,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  34  ;  Pascheles,  ibid. 

'  See  Haroack  and  Grlindlcr,  Berlin,  klin.  AVochenschr. .  1883;  Zeller.  Zeitschr.  f. 
physiol.  Cliem..  Bd.  8;  Kast.  Und.,  Bd.  11  ;  Blnz,  Arcli.  f.  exp.  Path.  u.  Pharm.,  Bd. 
28  ;  Zeehuisen,  Maly's  Jahresber.,  Bd.  23. 

>  Pfliiger's  Arch.,  Bd.  4. 

♦Smith,  Ptliiger's  Arch.,  Bdd.  53.  55,  57,  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  17  ; 
Salkowski.  Yirchow's  Arch.,  Bd.  66  ;  PlU'iger'-s  Arch.,  Bd.  39  ;  Goldniann,  Zeilsc».r.  f. 
physiol.  Chem.,  Bd.  9;  al.so  Baumann  and  Kast,  ibid.,  Bd.  14. 

'  Suudvik,  Maly's  Jahresber.,  Bd.  16  ;  Musculus  and  v.  Mering,  Ber.  d.  deutsch. 
chem.  Gesellsch.,  Bd.  8;  also  v.  Mering,  ibid.,  Bd.  15,  Zeitschr.  f.  physiol.  Chem.,  Bd. 
6  ;  Klllz.  Pfliiger's  Arch.,  Bdd.  28  and  33. 


478  URINE. 

The  aromatic  combinations'  pass,  as  far  as  we  know,  into  the  urine  as 
such  generally  after  a  previous  partial  oxidation  or  after  a  synthesis  with 
other  bodies.  That  the  benzol  ring  is  destroyed  in  the  body  in  certain 
cases  is  very  probable. 

The  fact  that  benzol  may  be  oxidized  outside  of  the  body  into  carbon 
dioxide,  oxalic  acid,  and  volatile  fatty  acids  has  been  known  for  a  long 
time;  and  as  in  these  cases  a  rupture  of  the  benzol  ring  must  take  place,  so 
also,  it  mij^t  be  admitted,  when  aromatic  substances  undergo  a  combustion 
in  the  animal  body  a  rapture  of  the  benzol  nucleus  with  the  formation  of 
fatty  bodies  must  first  take  place.  If  this  does  not  take  place,  then  the 
benzol  nucleus  is  eliminated  with  the  urine  as  an  aromatic  combination  of 
one  kind  or  another.  As  the  difficultly  destroyed  benzol  nucleus  can  pro- 
tect from  destruction  a  substance  belonging  to  the  fatty  series  when  con- 
jugated with  it,  which  is  the  case  with  the  glycocoll  of  hippuric  acid,  it 
seems  also  that  the  aromatic  nucleus  itself  may  be  protected  from  destruc- 
tion in  the  organism  by  syntheses  with  other  bodies.  The  aromatic  ethereal- 
sulphuric  acids  are  examples  of  this  kind. 

The  difficulty  in  deciding  whether  the  benzol  ring  itself  is  destroyed  in 
the  betdy  lies  in  the  fact  that  we  do  not  know  all  the  different  aromatic 
transformation  products  which  may  be  produced  by  the  introduction  of  any 
aromatic  substance  in  the  organism,  and  which  we  must  seek  for  in  the 
urine.  On  this  account  it  is  also  impossible  to  learn  by  exact  quantitative 
determinations  whether  or  not  an  aromatic  substance  introduced  or  absorbed 
appears  again  in  its  entirety  in  the  urine.  Certain  observations  render  it 
probable  that  the  benzol  ring,  as  above  mentioned,  is  at  least  in  certain 
cases  destroyed  in  the  body.  Sohotten,  Baumann,  and  others  have  found 
that  certain  amido-acids,  such  as  tyrosin,  phenylaniido-propionic  acid.,  and 
amido-ci7inamic  acid  when  introduced  into  the  body  cause  no  increase  in 
the  quantity  of  known  aromatic  substances  in  the  urine;  this  makes  a 
destruction  of  these  amido-acids  in  the  animal  body  seem  probable. 
JuVALTA  also  made  an  experiment  on  dogs  with  pldlialic  acid,  and  found 
that  it  was  in  great  part  destroyed.  The  benzol  derivatives  vary  in 
behavior  according  to  the  position  of  the  substitution,  for  as  found  by 
E.  Conx,"  among  the  di-derivates  the  ortho  compounds  are  more  readily 
destroyed  than  the  corresponding  meta-  or  para-compounds. 

An  oxidation  in  the  side  chain  of  aromatic  compounds  is  often  found, 
and  may  also  occur  in  the  nucleus  itself.      As  an  example,  benzol  is  first 


'  In  acconliiiice  with  custom  we  will  discuss  under  this  heading  the  homocyclic  ;is 
■well  as  the  heteiocylic  compounds. 

"  Schotten,  Zeitschr.  f.  pliysiol.  Chem  ,  Bdd.  7  and  8  ;  Bauraann,  ibid.,  Bd.  10,  S. 
130.  In  regard  to  the  behavior  of  tyrosin  see  especially  Blendennann,  ibid.,  Bd.  6  ; 
Schotien.  ihkl.,  Bd.  7  ;  Baas,  ibid.,  Bd.  11  ;  and  R.  Cohu,  ibid.,  Bd.  14;  Juvalta,  ibid.„ 
Bd.  13 ;  R.  Cohn,  ibid.,  Bd.  17. 


CASUAL   CONSTITUENTS.  479 

oxidized  to  oxybenzol  (Schultzen  and  Naunyn),  and  this  is  then  further 
in  part  converted  into  dioxyhenzols  (Baumann  und  Preussp.).  J^'aphthalin 
ii])pears  to  be  converted  into  oxyna])]ithalin,  and  probably  a  part  also  into 
(lioxynaphthalin  (Lesnik  and  M.  Nencki).  The  hydrocarbons  with  an 
aniido  or  iniido  grouji  may  also  be  oxidized  by  a  substitution  of  hydroxy! 
for  hydrogen,  especially  when  the  formation  of  a  derivative  with  the  para 
j)Osition  is  possible  (Klingenbekg).  For  example,  anilin,  CJI^. NH,  , 
])aRses  into  paramidophenol,  which  passes  into  the  urine  as  ethereal-sul- 
phuric acid,  1I,X.C,1I,.U.S0,.0II  (F.  Muller).  Acctanilid  is  in  part 
converted  into  acetyl  paramidophenol  (Jaffe  and  Hilbert,  K.  Mornek), 
and  carhazol  into  oxycarbazol  (Klingenberg  '). 

An  oxidation  of  the  side  chain  may  occur  by  the  hydrogen  atoms  being 
replaced  by  hydroxyl  as  in  the  oxidation  of  indol  and  skatol  into  indoxyl 
and  skatoxyl.  An  oxidation  of  the  side  chain  mav  also  take  place  with  the 
formation  of  carboxyl;  thus,  for  example,  iolnol,  0,11^.011,  (Schultzen  and 
Nauntn),  ethyl-benzol,,  CJI^.C^H^,  and  2)7-o])ylbeiizol,CJ:l^.CJ.i^  (Nencki 
and  Giacosa),'  besides  many  other  bodies,  are  oxidized  into  benzoic  acid. 
Cymol  is  oxidized  to  cumic  acid,  :rylol  to  toluic  acid,  methyl-pyridin  to 
pyridin-carbonic  acid,  in  the  same  way.  If  the  side  chain  has  several 
members,  the  behavior  is  somewhat  different.  Pheuyl-acetic  acid,  C  H  . 
CHj.COOII,  in  which  only  one  carbon  atom  exists  between  the  benzol 
nucleus  and  the  carboxyl,  is  not  oxidized,  but  is  eliminated  after  conjuga- 
tion with  glycocoll  as  phenaceturic  acid  (Salkoavski  ^).  Phenyl-propionic 
acid,  Cgllj.CH^.CIIj.COOlI,  with  two  carbon  atoms  between  the  benzol 
nucleus  and  the  carboxyl,  is,  on  the  contrary,  oxidized  into  benzoic  acid.* 
Aromatic  amido-acids  with  three  carbon  atoms  in  the  side  chain,  and  where 
tlie  Nil,  group  is  bound  to  the  middle  one,  as  in  iyrosin,  o'-oxyphenyl- 
amido-propionic  acid,  0.11,(011). CH,.CII(NH,).COOH,  and  (x-phenyl- 
amido-pro])\onic  acid,  CJI^. CII.^.CH(NH,),COOH,  seem  to  be  in  great  part 
burnt  within  the  body  (see  above).  Phenylamido-accfic  acid,  which  has 
only  two  carbon  atoms  in  the  side  chain,  C,H^.  CH(NHJCOOH,  acts 
differently,  passing  into  mandelic  acid,  phenyl-glycolic  acid,  0,11^.011(011). 
coon  (Schotten'). 

'  Schultzen  and  Nannyii,  Reicbert  and  Du  Bois-Rcymond's  Arch..  1867;  Banmann 
and  Preusse,  Zuitschr.  f.  pbysiol.  Cbem.,  Bd.  3,  S.  156.  See  also  Nencki  and  Giarosa, 
ibid.,  Bd.  4  ;  Lcsnik  and  Nencki,  Arch.  f.  exp.  Path.  u.  Pharni.,  Bd.  24;  F.  Muller, 
Deutscb.  med.  Wochenschr.,  18S7  ;  Jaffe  and  Hilbcrl.  Ztitschr.  f.  jWiysiol.  Cheift  ,  Hd. 
12;  Mornor,  ibid.,  Bd.  13;  Klingenberg,  "  Studien  iiher  die  Oxydation  aroniatiscber 
Substauzeu,"  etc.  Iiiaug.-Diss.  Rostock,  1891.  In  regard  to  formanilid,  which  acts 
essentially  as  acctanilid.  see  Kleine,  Zeitecbr.  f.  pbysiol.  Chem.,  Bd.  23. 

^  Ibid.,  Bd.  4. 

*  Ibid..  Bdd.  7  and  9. 

*  See  E  and  H.  Salkowski,  Ber.  d.  deutscb.  chem.  Gesellsch.,  Bd.  13. 

*  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  8. 


480  URINE. 

If  several  side  chains  are  present  in  the  benzol  nucleus,  then  only  one 
is  always  oxidized  into  carboxyl.  Thus  xylol,  Q^^{G11^)^ ,  is  oxidized  into 
toluic  acid,  CgH^(CHJCOOH  (Schultzex  and  Naui^tn),  mesitylen, 
0,11,(003)3,  into  mesitylenic  acid,  0Ji3(0H,),.C00H  (L.  Nencki),  and 
cymol  into  cumic  acid  (M.  Nencki  and  Ziegler'). 

Syntheses  of  aromatic  substances  with  other  atomic  groups  occur  fre- 
quently. To  these  syntheses  belongs,  in  the  first  rank,  the  conjugation  of 
benzoic  acid  with  glycocoll  to  form  Mpiniric  acid,  first  discovered  by 
WoHLER.  All  the  numerous  aromatic  substances  which  are  converted  into 
benzoic  acid  in  the  body  are  voided  partly  as  hippuric  acid.  This  statement 
is  not  true  for  all  classes  of  animals.  According  to  the  observations  of 
Jaffe,'^  benzoic  acid  does  not  pass  into  hippuric  acid  in  birds,  but  into 
another  nitrogenous  acid,  ornithuric  acid,  G.^Jl^^^fi^.  This  acid  yields  as 
splitting  products,  besides  benzoic  acid,  ornithin,  a  body  which  has  been 
spoken  of  on  page  68.  Not  only  are  the  oxyienzoic  acids  and  the  sub- 
stituted benzoic  acids  conjugated  with  glycocoll,  forming  corresponding 
hippuric  acids,  but  also  the  above-mentioned  acids,  toluic,  7nesitylenic, 
cumic,  and  plienylacetic  acids.  These  acids  are  voided  as  toluric,  mesityle- 
nurioi  cuminuric,  and  i^lienaceturic  acids. 

It  must  be  remarked  in  regard  to  the  oxybenzoic  acids  that  a  conjuga- 
tion with  glycocoll  has  only  been  shown  with  salicylic  acid  and  p-oxy- 
benzoic  acid  (BertagjSTIXI,  Baumann,  and  Herter,  and  others),  while 
Baumann"  and  Herter  *  find  it  only  very  probable  for  m-oxybenzoic  acid. 
The  oxybenzoic  acids  are  also  in  part  eliminated  as  conjugated  sulphuric 
acids,  which  is  especially  true  for  m-oxybenzoic  acid.  We  have  the  in- 
vestigations on  m-amidobenzoic  acid  in  regard  to  the  transformation 
of  amidobenzoic  acids,  Salkowski  found,  as  was  later  confirmed  by 
R,  CoiiN,*  that  m-amidobenzoic  acid  passes  in  part  into  uramidohenzoic 
acid,  H,N.OO,HN.O,H^.OOOH.  It  is  also  in  part  eliminated  as  amido- 
hippuric  acid. 

The  substituted  aldehydes  are  of  special  interest  as  substances  which 
undergo  conjugation  with  glycocoll.  According  to  the  investigations  of 
R.  OoiiN""  on  this  subject  o-nitrobejizaldehyde  when  introduced  into  a  rabbit 
is  only  in  a  very  small  part  converted  into  nitrobenzoic  acid,  and  the  chief 
mass,  about  00^,  is  destroyed  in  the  body.  According  to  Sieber  and 
Smirxow'  m-nitrohenzaldehyde  passes  in  dogs  into  m-nitrohippuric  acid, 

'  L.  Nencki,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  1  ;  JSTencki  and  Ziegler,  Ber.  d. 
deutsch.  chcm.  Gesellsch.,  Bd.  5.     See  also  O.  Jacobsen,  ibid.,  Bd.  13. 

'  Ibid.,  Bdd.  10  and  11. 

''  Zeitschr.  f.  pliysiol  Chem.,  Bd.  1,  where  Bertagnini's  work  is  also  cited.  See  also 
Dautzeiiberg,  Maly's  .Jahresber.,  Bd.  11,  S.  231. 

■•  Salkow.ski,  Zeitschr.  f.  physiol.  Chem.,  Bd.  7;  Cohn,  ibid.,  Bd.  17. 

»  ZeiUschr.  f.  physiol.  Chem.,  Bd.  17. 

*  Mouatshefte  f.  Chem.,  Bd.  8. 


CASUAL   CONSTITUENTS.  481 

and  according  to  C'oiiN  into  nrea  m-nitrohippnrate.  In  rabbits  the 
beliavior  is  (Hiite  different  according  to  Coiix.  In  tliis  case  not  only  does 
an  oxidation  of  the  aldehyde  into  benzoic  acid  take  place,  but  the  nitro 
group  is  also  reduced  to  an  amido  group,  and  finally  acetic  acid  attaches 
itself  to  the  amido  group  with  the  expulsion  of  water,  so  that  the  final 
product,  m-acetylamidobenzoic  acid.,  CH^.CO.NH.CJI^.COOII,  is  the 
result.  This  process  is  analogous  to  the  behavior  of  furfurol,  and  the 
reduction  does  not  take  place  in  the  intestine,  but  in  the  tissue.  The 
p-nitrobenzaldehyde  acts  in  rabbits  in  part  like  the  m-aldehyde  and  passes 
in  part  into  p-arcfylamidohenzoic  acid.  Another  part  is  converted  into 
p-nitrobenzoic  acid,  and  the  urine  contains  a  chemical  combination  of  equal 
parts  of  these  two  acids.  According  to  Si"eber  and  Smirnow  p-nitro- 
benzaldehyde yields  only  nrea  p-nitrohippurate  in  dogs.  The  above- 
mentioned  pi/ridin-car/)0)iic  acid,  formed  from  methyl  pyridin  (o'-picolin), 
passes  into  the  urine  after  conjugation  with  glycocoll  as  a-pyridinuric 
acid. ' 

To  those  substances  which  undergo  a  conjugation  with  glycocoll  belongs 
furfurol  (the  aldehyde  of  pyromucic  acid),  which,  when  introduced  into 
rabbits  and  dogs,  as  shown  by  Jaffk  and  Cohx,  is  first  oxidized  into 
pyromucic  acid  and  then  this  eliminated  a^  j^yromxiciiric  acid,  C,II,X^O, 
after  conjugation  with  glycocoll.  In  birds  this  behavior  is  different, 
namely,  in  them  the  acid  is  conjugated  to  another  substance,  ornitJiin, 
CjII,jN,0„ ,  which  is  probably  diamidovalerianic  acid,  forming  j)y  row  a  ci7ior- 
thuric  acid.  Similar  to  the  oxidation  of  furfurol,  thiophen,  CJI^S,  corre- 
sponding to  furfuran,  is  oxidized  to  tliiophenic  acid,  which,  according  to 
Jaffe  and  Levy,"  is  conjugated  with  glycocoll  in  the  body  (rabbits)  and 
eliminated  as  thiophenuric  acid,  C,II,NSO,. 

Furfurol  also  undergoes  conjugation  with  glycocoll  in  other  forms  in 
mammals.  Thus  Jaffe  and  Cohx  found  that  it  is  in  part  combined  with 
acetic  acid,  forming  furftiracrylic  acid,  CJI3O.CH:  CH.COOH,  which 
passes  into  the  urine  coupled  Avitli  glycocoll  as  furfuracryluric  acid. 

Another  very  important  synthesis  of  aromatic  substances  is  that  of  the 
ethercal-.snlphuric  acids.  Phenols  and  chiefly  the  hydroxylated  aromatic 
hydrocarbons  and  their  derivatives  are  voided  as  ethereal-sulphuric  acids, 
according  to  Baumax'x,  IIerter,  and  others.' 

A  conjugation  of  aromatic  acids  with  sulphuric  acid  occurs  less  often. 
The   two   above-mentioned    aromatic    acids,   p-oxyphenylacetic    acid    and 

'  III  lecaid  to  tlip  extensive  literature  on  glycocoll  conjiisxatioiis  we  refer  the  reader 
to  O.  Kiihliiig,  Ueber  SlofTwechselprodukle  aromalisclier  Korpor.  Inaug.-Diss.  Berlin, 
1887. 

'  Jaffe  and  Cobu.  Ber.  d.  deutscb.  cbem.  Gesellscli.,  Bdd.  20  .'uid  21  ;  witb  Levy, 
ihid.,  Bd.  21. 

'  In  rejiard  to  the  literature  see  O.  Kilbliug,  1.  c. 


482  URINE. 

p-oxyplienylpropionic  acid,  are  in  part  eliminated  in  this  form,  Gentisinic 
acid  (hydroclii non-carbonic  acid)  increases,  according  to  Likhatscheff,' 
also  the  quantity  of  ethereal-sulphuric  acid  in  the  urine,  and  according  to 
EosT  the  same  occurs,  contrary  to  the  older  statements,  with  gallic  acid, 
(trioxybenzoic  acid)  and  tannic  acid.'' 

While  acetoplienoii  (phenylmethyl  ketone),  CJI^.CO.CHj,  as  shown  bj 
M.  Nencki,  is  oxidized  to  benzoic  acid  and  eliminated  as  hippuric  acid, 
the   aromatic   oxyketones  with   hydroxyl  groups,  such  as  resacetoplienon,. 

C.H3(OH)(OH)(CO.CH3),  paraoxypropiophenon,  0,H,(OH)(COGH,.CHJ, 

12  3  4 

and  (jallacetoplienen,  CJI.^(0H)(0H)(0H)(C0.CE[3),  pass  into  the  urine 
without  previous  oxidation  as  ethereal-sulphuric  acids  and  in  part  after 
conjugation  Avith  glycnronic  acid  (Nencki  and  Eekowski  '). 

Euxantlion,  Avhich  is  also  an  aromatic  oxyketone,  passes  into  the  urine  as 
euxanthic  acid  after  a  previously  mentioned  conjugation  with  glycnronic 
acid.  A  conjugation  of  other  aromatic  substances  with  glycnronic  acid, 
which  last  is  protected  from  combustion,  occurs  rather  often.  Camphor, 
C,pH  gO,  when  given  to  a  dog  is  first  converted  by  oxidation  into  camphoral, 
C,gH^(OH)0,  and  by  conjugation  with  glycnronic  acid  into  campho- 
glyciironic  acid  (Schmiedeberg).  The  phenols,  as  above  stated  (page  445), 
pass  in  part  as  conjugated  glycnronic  acids  into  the  urine.  The  same  is 
true  for  the  homolo^ues  of  phenols,  for  certain  substituted  phenols,  for 
naplitliols,  lorneol,  menthol,  turpentine,  and  many  other  aromatic  sub- 
stances.* Orthonitrotoluol  in  dogs  passes  first  into  o-nitrobenzyl  alcohol 
and  then  into  a  conjugated  glycuronic  acid,  nronitj'otoluolic  acid  (Jaffe^). 
The  glycuronic  acid  split  off  from  the  conjugated  acid  is  Icevogyrate  and 
hence  not  identical  with  the  ordinary  glycuronic  acid,  but  isomeric.  Lidol 
and  skatol  seem,  as  above  stated  (page  449  and  450),  to  be  eliminated  in 
the  urine  partly  as  conjugated  glycuronic  acids. 

A  synthesis  in  which  compounds  containing  sulphur,  mercapturic  acid, 
are  formed  and  eliminated,  conjugated  with  glycuronic  acid,  occurs  when 
chlorine  and  bromine  derivates  of  benzol  are  introduced  into  the  organism 
of  dogs  (Baumanx   and  Preusse,  Jaffe").     Thus  chlorhcnzol   combines 

'  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  21. 

"  lu  regard  to  the  behavior  of  gallic  and  tannic  acids  in  the  animal  body  see  C.  MiJr- 
ner,  Zeitsciir.  f.  physiol.  Cliem.,  Bd.  16,  which  also  contains  the  older  literature;  also 
Harnack,  ibid.,  Bd.  24,  and  Rost,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  38,  and  Sitzungs- 
ber.  d.  GeselLsch.  zur  Beford.  d.  ges.  Nalurwiss.  zu  iMarburg,  1898. 

'  Arch.  d.  scienc.  biol.  de  St.  Petersbourg,  Tome  3,  and  Ber.  d.  deutsch.  chem.  6e- 
sellscli.,  Bd.  27. 

••  See  O.  Klihling,  1.  c,  which  gives  the  literature  up  to  1887  ;  also  E.  Kalz,  Zeitschr. 
f.  Biologic,   Bd.  27. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 

*  Baumann  and  Preusse,  Zeitschr.  f.  physiol.  Chem.,  Bd,  5;  Jaffe,  Ber.  d.  deutsch. 
chem.  Gesellsch.,  Bd,  12. 


CASUAL   CONSTITUENTS  483 

with  CYSTEIN,  an  intermediate  decomposition  product  of  proteids  which  is 
closely  allied  to  cystin  (see  below),  forming  chlorphenyhnercapturic  acid, 
C,,II„C1S\0,.  On  boiling  with  mineral  acid  this  compound  decomposes, 
into  acetic  acid  and  chlorphenylcystein,  CJI^Cl.CjII.NSO,. 

Pyridin,  CJI^X,  which  does  not  combine  either  with  glycuronic  acid  or 
with  snlphuric  acid  after  previous  oxidation,  shows  a  special  Ijehavior.  It 
takes  up  a  methyl  group  as  found  by  Ills  and  later  confirmed  by  CoiiN,' 
and  forms  an  ammonium  combination,  inethylpyridyl-ammonium  hydroxyl^ 
IIO.('II,.X'CJI,. 

Several  alkaloids,  such  as  quinin,  tnorphin,  and  sirych?ii7i,  may  pass 
into  the  urine.  After  turpentine,  balsam  of  cojjaiva,  and  resins  these 
may  appear  in  the  urine  as  resin  acids.  Different  kinds  of  coloring 
matters,  such  as  alizarin,  crysophanic  acid,  after  rhubarb  or  senna,  and 
the  coloring  matter  of  the  hhieberry,  etc.,  may  also  pass  into  tlie  urine. 
After  rhubarb,  senna,  or  santonin  the  urine  assumes  a  yellow  or  greenish- 
yellow  color,  which  is  transformed  into  a  beautiful  red  color  by  the  addition 
of  alkali.  Phenol  produces,  as  above  mentioned,  a  dark-brown  or  dark- 
green  color  which  depends  mainly  on  the  decomposition  products  of  hydro- 
chinon  and  humin  substances.  After  naplitlialin  the  urine  has  a  dark 
color,  and  several  other  medicines  produce  a  special  coloration.  Thus 
kairin  often  gives  a  yellowish-green  hue,  and  the  nrine  darkens  when 
exposed  to  the  air;  thalUn  gives  a  greenish-brown  color  which  is  marked 
green  in  thin  layers,  and  antiptyrin  gives  a  yellow  to  blood-red.  After 
balsam  of  copaiva  the  urine  becomes,  when  strongly  acidified  with  hydro- 
chloric acid,  gradually  rose  and  purple-red.  After  naphthalin  or  naphthol 
the  urine  gives  with  concentrated  sulphuric  acid  (1  c.c.  concentrated  acid 
and  a  few  drops  of  urine)  a  beautiful  emerald-green  color,  which  is 
probably  due  to  naphthol-glycuronic  acid.  Odoriferous  bodies  also  pass 
into  the  urine.  After  asparagus  the  urine  acquires  a  sickly  disagreeable 
odor  which  is  probably  due  to  methylmercaptan,  according  to  M.  Xexcki." 
After  turpentine  the  urine  may  have  a  peculiar  odor  similar  to  that  of.' 
violets. 

VI.  Ptitliological  Constituents  of  Urine. 

Proteid.  The  appearance  of  slight  traces  of  proteid  in  normal  urines 
has  been  repeatedly  observed  by  many  investigators,  such  as  PostfER, 
Plosz,  y.  Xoordex,  Leube,  and  others.  According  to  K.  Morxer'  pro- 
teid regularly  occurs  as  a  normal  urinary  constituent  to  the  extent  of  22-78 

'  His,  Arch.  f.  exp.  Path.  u.  Phaim.,  Bd.   22;  Cobu,  Zeitschr.  f.  pbysiol.   Chem., 
B(l.  18. 

-  Arch.  f.  e.xp.  Path.  u.  Phann.,  Bd.  28. 
'  Skand.  Arch.  f.  Physiol.,  Bd.  6. 


484  URINE. 

milligrams  jier  litre.  Frequently  traces  of  a  substance  similar  to  a  nacleo- 
albamin,  and  which  is  easily  mistaken  for  mucin,  are  found  in  the  urine. 
In  diseased  conditions  proteid  occurs  in  the  urine  in  a  variety  of  cases. 
The  albuminous  bodies  whicli  most  often  occur  are  serglobulin  and  seral- 
bumin. Albumoses  and  pejitones  also  sometimes  occur.  The  quantity  of 
2irofceid  in  the  urine  is  in  most  cases  less  than  5  p.  m.,  rarely  10  p.  m.  and 
only  very  rarely  does  it  amount  to  50  p.  m,  or  over. 

Among  the  many  reactions  proposed  for  the  detection  of  proteid  n 
urine,  the  following  are  to  be  recommended: 

The  Heat  Test.  Filter  the  urine  and  test  its  reaction.  An  acid  urine 
may,  as  a  rule,  be  boiled  without  further  treatment,  and  only  in  especially 
acid  urines  is  it  necessary  to  first  treat  witli  a  little  alkali.  An  alkaline 
urine  is  made  neutral  or  faintly  acid  before  heating.  If  the  urine  is  poor 
in  salts,  add  jV  vol,  of  a  saturated  common-salt  solution  before  boiling; 
then  heat  to  boiling-jjoint,  and  if  no  precipitation,  cloudiness,  or  opalescence 
appears,  the  urine  in  question  contains  no  coagulable  proteid,  but  it  may 
contain  albumoses  or  j)eptones.  If  a  precipitate  is  produced  on  boiling, 
this  may  consist  of  proteid,  or  of  earthy  phosphates,  or  of  both.  The 
simple-acid  calcium  phosphate  decomposes  on  boiling,  and  normal  phos- 
plmte  may  separate.  The  proper  amount  of  acid  is  now  added  to  the 
urine,  so  as  to  prevent  any  mistake  caused  by  the  presence  of  earthy 
phosphates,  and  to  give  a  better  and  more  flocculent  precipitate  of  the 
proteid.  If  acetic  acid  is  used  for  this,  then  add  1-2-3  drops  of  a  25^  acid 
to  each  10  c.c.  of  the  urine,  and  boil  after  the  addition  of  each  drop.  On 
using  nitric  acid,  add  1-2  drops  of  the  25^  acid  to  each  c.c.  of  the  boiling- 
hot  urine. 

On  using  acetic  acid,  when  the  quantity  of  proteid  is  very  small,  and 
especially  when  the  urine  was  originally  alkaline,  the  proteid  may  sometimes 
remain  in  solution  on  the  addition  of  the  above  quantity  of  acetic  acid. 
If,  on  the  contrary,  less  acid  is  added,  the  precipitate  of  calcium  phosphate, 
which  forms  in  amphoteric  or  faintly  acid  urines,  is  liable  not  to  dissolve 
completely,  and  this  may  cause  it  to  be  mistaken  for  a  proteid  precipitate. 
If  nitric  acid  is  used  for  the  heat  test,  the  fact  must  not  be  overlooked  that 
after  the  addition  of  only  a  little  acid  a  combination  between  it  and  the 
proteid  is  formed  which  is  soluble  on  boiling  and  which  is  only  precipitated 
bv  an  excess  of  the  acid.  On  this  account  the  large  quantity  of  nitric  acid, 
.us  suggested  above,  must  be  added,  but  in  this  case  a  small  part  of  the 
proteid  is  liable  to  be  dissolved  by  the  excess  of  the  nitric  acid.  When  the 
acid  is  added  after  boiling,  which  is  absolutely  necessary,  the  liability  of  a 
mistake  is  not  so  great.  It  is  on  these  grounds  that  the  heat  test,  although 
it  gives  very  good  results  in  the  hands  of  experts,  is  not  recommended  to 
physicians  as  a  positive  test  for  proteid. 

A  confounding  with  mucin,  Avhen  this  body  occurs  in  the  urine,  is  easily 
prevented  in  the  heat  test  with  acetic  acid,  by  acidifying  another  portion 
with  acetic  acid  at  the  ordinary  temperature.  Mucin  and  nucleoalbumin 
substances  similar  to  mucin  are  hereby  precipitated.  If  in  the  performance 
of  the  heat  and  nitric-acid  test  a  precipitate  first  aj^pears  on  cooling  or  is 
strikingly  increased,  then  this  shows  the  presence  of  albumoses  in  the  urine, 
either  alone  or  mixed  with  coagulable  proteid.     In   this  case   a  further^ 


PROTEIDS.  485 

investigation  is  necessary  (see  below).  In  a  nrine  rich  in  urates  a  precipitate 
consisting  of  uric  acid  separates  on  cooling.  Tliis  precipitate  is  colored, 
sandy,  and  hardly  to  be  niiataken  for  an  albiunose  or  proteid  preci])itate. 

IIkfj-Ku's  test  is  performed  as  fallows  (see  page  2<i):  The  urine  is  very 
carefully  floated  on  the  surface  of  nitric  acid  in  a  test-tube.  The  presence 
of  proteid  is  shown  by  a  white  ring  between  the  two  liquids.  With  this 
test  a  red  or  reddish-violet  transparent  ring  is  always  obtained  witli  nornud 
urine;  it  depends  on  the  indigo  coloring  matters  and  can  hardly  be  mistaken 
for  the  white  or  whitish  proteid  ring,  and  this  last  must  not  be  mistaken 
for  the  ring  produced  by  bile-pigments,  in  a  urine  rich  in  urates  anotlier 
complication  may  occur,  dne  to  the  formation  of  a  ring  produced  by  the 
])recipitated  uric  acid.  The  uric-acid  ring  does  not  lie,  like  the  proteid 
ring,  between  the  two  liquids,  but  somewhat  higher.  For  this  reason  we 
may  often  have  two  simultaneous  rings  with  urines  rich  in  urates  and  yet 
not  containing  very  much  proteid.  The  disturbance  caused  by  uric  acid  is 
easily  prevented  by  diluting  the  urine  with  1-2  vol.  water  before  performing 
the  test.  The  uric  acid  now  remains  in  solution,  and  the  delicacy  of 
Heller's  test  is  so  great  that  after  dilution  only  in  the  presence  of  insig- 
nificant traces  of  proteid  does  this  test  give  negative  results.  In  a  urine 
very  rich  in  urea  a  ring-like  separation  of  urea  nitrate  may  also  appear. 
This  ring  consists  of  shining  crystals,  and  it  does  not  appear  in  the  pre- 
viously diluted  urine.  A  confusion  with  resinous  acids,  which  also  give  a 
whitish  ring  with  this  test,  is  easily  prevented,  since  these  acids  are  soluble 
on  the  addition  of  ether.  Stir,  add  ether  and  carefully  shake  the  contents 
of  the  test-tube.  If  the  cloudiness  was  due  to  resinous  acids,  the  urine 
gradually  becomes  clear,  and  on  evaporating  the  ether  a  sticky  residue  of 
resinous  acids  is  obtained.  A  liquid  which  contains  pure  mucin  does  not 
give  a  precipitate  with  this  test,  but  it  gives  a  more  or  less  strongly 
opalescent  ring,  which  disappears  on  stirring.  The  liquid  does  not  contain 
any  precipitate  after  stirring,  but  is  somewhat  opalescent.  If  a  faint,  not 
wholly  typical  reaction  is  obtained  with  Heller's  test  after  some  time  with 
undiluted  urine,  while  the  diluted  urine  gives  a  pronounced  reaction,  this 
shows  the  presence  of  the  substance  which  used  to  be  called  mucin  or 
nucleoalbumin.  In  this  case  proceed  as  described  below  for  the  detection 
of  nucleoalbumin. 

If  we  bear  in  mind  the  above-mentioned  possible  errors  and  the  means 
by  which  they  may  be  prevented,  there  is  hardly  another  test  for  proteid  in 
the  urine  which  is  at  the  same  time  so  easily  performed,  so  delicate,  and  so 
positive  as  Heller's.  With  this  test  even  0.002^  albumin  may  be  detected 
without  difficulty.  Still  the  student  should  not  be  satisfied  with  this  test 
alone,  but  apply  at  least  a  second  test,  such  as  the  heat  test.  In  performing 
this  test  the  (primary)  albnmoses  are  also  precipitated. 

The  reaction  icith  metaphosphoric  acid  (see  page  20)  is  very  convenient 
and  easily  performed.  It  is  not  quite  so  delicate  and  positive  as  Heller's 
test.     The  albnmoses  are  also  precipitated  by  this  reagent. 

Reaction  with  Acetic  Acid  and  Potassium  Fcrrocyanide.  Treat  the  urine 
first  with  acetic  acid  until  it  contains  about  2f^,  and  then  add  drop  by  drop 
a  potassium-ferrocyanide  solution  (1  :  20),  carefully  avoiding  an  excess. 
This  test  is  very  good,  and  in  the  hands  of  experts  it  is  even  more  delicate 
than  Heller's.  In  the  presence  of  very  small  quantities  of  proteid  it 
requires  more  jiractice  and  dexterity  than  Heller's,  as  the  relative  qnan- 


486  URINE. 

titles  of  reagent,  proteid,  and  acetic  acid  influence  the  result  of  the  test. 
Tlie  quantity  of  salts  in  the  urine  likewise  seems  to  have  an  influence.  This 
reagent  also  precipitates  albumoses. 

Spiegleu's  Test.  Spiegler  recommends  a  soluliou  of  8  parts  mercuric  chloride,  4 
parts  tartaric  acid,  20  parts  glycerin,  and  200  parts  water  as  a  very  delicate  reagent  for 
proteid  iu  tlie  urine.  A  test-tube  is  half  filled  with  this  reagent,  and  the  urine  allowed 
to  flow  upon  its  surface  drop  by  drop  from  a  pipette  along  the  wall  of  the  test-tube.  In 
the  presence  of  proteid  a  white  ring  is  obtained  at  the  point  of  contact  between  the  two 
liquids.  The  delicacy  of  this  test  is  1  ;  350000.  Jolles  '  does  not  consider  this  reagent 
suited  for  urines  verv  poor  in  chlorine,  and  for  this  reason  he  has  changed  it  as  follows  : 
10  grm.  mercuric  chloride,  20  grm.  succinic  acid.  10  grm.  NaCl,  and  500  cc.  water. 

Roch's  Test.  Treat  the  urine  either  with  a  2,0%  watery  solution  of  sulpho.salicylic  acid 
or  a  few  crystals  of  the  acid.  This  reagent  does  not  precipitate  the  uric  acid  or  the  resin 
acids.' 

As  every  normal  urine  contains  traces  of  proteid,  it  is  apparent  that  very 
delicate  reagents  are  only  to  be  used  with  the  greatest  caution.  For 
ordinary  cases  Heller's  test  is  snfhoiently  delicate.  If  no  reaction  is 
obtained  with  this  test  within  24  to  3  minutes,  the  urine  tested  contains  less 
than  0,003,^  proteid,  and  is  to  be  considered  free  from  proteid  in  the 
ordinary  sense. 

The\ise  of  precipitating  reagents  presumes  that  the  urine  to  be  investi- 
gated is  perfectly  clear,  especially  in  the  presence  of  only  very  little  proteid. 
The  urine  must  first  be  filtered.  This  is  not  easily  done  with  urine  con- 
taining bacteria,  but  a  clear  urine  may  be  obtained,  as  suggested  by 
A.'JOLLES,"  by  shaking  the  nrine  with  infusorial  earth. 

The  different  color  reactions  cannot  be  directly  used,  especially  in  deep- 
colored  urines  which  only  contain  little  proteid.  The  common  salt  of  the 
nrine  lias  a  disturbing  action  on  Millox's  reagent.  To  prove  more  posi- 
tively the  presence  of  proteid,  the  precipitate  obtained  in  the  boiling  test 
may  be  filtered,  washed,  and  then  tested  with  Millon's  reagent.  The 
precipitate  may  also  be  dissolved  in  dilute  alkali  and  the  binret  test  applied 
to  the  solution.  The  presence  of  albumoses  or  peptones  in  the  urine  is 
directly  tested  for  by  this  last-mentioned  test.  In  testing  the  urine  for 
proteid  one  should  never  be  satisfied  with  one  test  alone,  but  apply  the 
heat  test  and  Heller's  or  the  potassiuin-ferrocyanide  test.  In  using  the 
heat  test  alone  the  albumoses  may  be  easily  overlooked,  but  these  are 
detected,  on  the  contrary,  by  Heller's,  or  the  potassium  ferrocyanide  test. 
If  we  use  only  one  of  "these  tests,  we  get  no  sufficient  intimation  of  the 
kind  of  proteid  present,  whether  it  consists  of  albumoses  or  coagulable 
proteid. 

For  practical  purposes  several  dry  reagents  for  proteid  have  been  recommended.  Be- 
sides the  metaphosphoric  acid  may  be  mentioned  Stutz's  or  Fuubringek's  gelatiu 
capsules,  which  contain  mercuric  chloride,  sodium  cliloride,  and  citric  acid  ;  and  Geiss- 
ler's  albumin-test  papers,  which  consist  of  strips  of  lilter- paper  wliich  have  been  dipped 
in  a  solution  of  citric  acid  and  also  mercuric-chloride  and  potassium-iodide  solution  and 
then  dried. 

If  the  presence  of  proteid  has  been  positively  proved  in  the  urine  by  the 
above  tests,  it  then  remains  necessary  to  determine  the  variety. 

'  Spiegler,  Wien.  klin.  "Wochenschr.,  1892,  and  Centralbl.  f.  d.  klin.  Med.,  1893; 
JoUes,  Zeitschr.  f.  physiol.  Chem.,  Bd.  21. 

■'  Pliarmaceut.  Centralhalle,  1889,  and  Zeitschr.  f.  anal.  Chem.,  Bd.  29. 
="  Zeitschr.  f.  anal.  Chem.,  Bd.  29. 


ALDUMOSES  AM)  PEPTONE  487 

The  Detection  of  Globulin  ond  Allnitnin.  In  detecting  sergiobulin  the 
Tirine  is  exactly  nentrali/.ed,  filtered,  and  treated  witli  magnesium  snlpliate 
in  substance  until  it  ia  completely  saturated  at  the  ordinary  tc^nperature,  or 
with  an  e«|ual  volume  of  a  saturated  neutral  solution  of  ammonium  sul- 
phate. In  both  cases  a  white,  llocculent  precipitate  is  formed  in  the 
presence  of  globulin.  In  using  ammonium  sulphate  witli  a  urine  rich  iu 
urates  a  precipitate  consisting  of  ammonium  urate  may  separate.  This 
precipitate  does  not  appear  immediately,  but  only  after  a  certain  time,  and 
it  must  not  be  mistaken  for  the  globulin  precipitate.  In  detecting  ser- 
albumin heat  the  filtrate  from  the  globulin  precipitate  to  boiling-point  or 
add  about  Ifii  acetic  acid  to  it  at  the  ordinary  temperature. 

AJl)U))Wses  and  pepto)ies  liave  been  repeatedly  found  in  the  urine  in 
different  diseases.  Reliable  reports  are  at  hand  on  the  occurrence  of  albu- 
moses  in  the  urine.  The  statements  in  regard  to  the  occurrence  of  peptones  ' 
date  in  part  from  a  time  when  the  conception  of  albumoses  and  peptones 
was  different  from  that  of  the  present  day,  and  in  part  they  are  based 
upon  investigations  using  untrustworthy  methods.  True  peptones  have 
not,  it  seems,  been  detected  in  urine,  and  what  has  been  designated  as  urine 
peptone  seem  to  have  been  chiefly  deutero-albumose. 

In  detecting  the  albumoses  the  proteid-free  urine,  or  urine  boiled  with 
addition  of  acetic  acid,  is  saturated  with  ammonium  sulphate,  which  precipi- 
tates the  albumoses.  Several  errors  are  here  possible.  The  urobilin,  which 
may  give  a  reaction  similar  to  the  biuret  reaction,  is  also  precipitated  and 
may  lead  to  mistakes  (Salkowski,  Stokvis").  A  small  quantity  of  the 
proteid  may  remain  in  solution  in  coagulation  which  may  be  i)recipitated 
by  the  ammonium  sulphate  and  be  mistaken  for  albumoses.  The  coagulable 
proteid  may  be  completely  precipitated  by  saturating  with  ammonium  sul- 
phate iu  boiling  solution;  but  according  to  Devoto'  small  quantities  of 
albumose  may  be  formed  from  the  proteid  by  heating  for  a  long  time  with 
the  salt.  On  heating  for  a  short  time  no  such  formation  of  albumose  takes 
l^lace,  and  the  proteids  are  completely  coagulated. 

For  these  reasons  Baxo  *  has  suggested  the  following  method  for  the 
detection  of  albumoses  in  the  presence  of  coagulable  proteid.  The  urine  is 
heated  to  boiling  with  ammonium  sulphate  (8  parts  to  10  parts  urine)  and 
boiled  for  a  few  seconds.  The  still  hot  liquid  is  centrifuged  for  -^  to  1 
minute  and  separated  from  the  sediment.  The  urobilin  is  removed  from 
this  by  extraction  with  alcohol.  The  residue  is  suspended  iu  a  little  water, 
heatetl  to  boiling,  filtered,  whereby  the  coagulable  proteid  is  retained  on 
the  filter,  and  any  urobilin  still  present  in  the  filtrate  is  shaken  out  with 
chloroform.  The  watery  solution,  after  removal  of  the  chloroform,  is  used 
for  the  biuret  test.  For  clinical  pur})oses  this  method  is  very  serviceable. 
In  regard  to  other  more  complicated  methods  we  refer  to  IIurPERT- 
Neubauer,  Ham-Analyse,  10.  Aufl. 

'  Iu  regard  to  the  litorature  ou  albumoses  niul  peptones  in  urine  see  Hiippeit-Neu- 
bauer,  Harn-Analyse,  10.  Auti.,  S.  466  to  492  ;  also  A.  Stollregen,  Ueber  das  Voikommen 
von  Pepton  im  Ilarn,  Sputum  und  Eiter  (Inaug.Diss..  Dorpat,  1891)  ;  H.  Hirsclifeldt. 
Ein  Beitiag  zur  Frage  der  Peptonurie  (Inaiig.  Diss.,  Dorpat,  1892)  ;  and  espcciall}- 
Stadelmaiin,  Untersuchungea  Uber  die  Peptonurie.     Wiesbaden,  1894. 

^  Salkowski,  Berlin,  klin.  "Wocbenscbr.,  1897  ;  Stokvis,  Zeitscbr.  f.  Biologic,  Bd.  34. 

'  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  15. 

*  Deutscb.  med.  Wocbenscbr.,  1898. 


488  URINE. 

If  the  albnnioses  have  besQ  preciiMtate4  from  a  larger  portion  of  urine 
bv  atninoiiiuni  sulphate,  this  precipitate  is  tested  for  the  i^reseuce  of  different 
albnnioses  for  the  reasons  given  in  Chapter  II, 

Tlie  following  serves  as  a  preliminary  determination  of  tJie  kind  of 
albumoses  jiresent  in  the  urine.  If  the  urine  contains  only  deuteroalbamose 
it  does  not  become  cloudy  on  boiling,  does  not  give  Heller's  test,  does  not 
become  cloudy  on  saturating  ■\vitli  XaCl  in  neutral  reaction,  but  does  become 
cloudy  on  adding  acetic  acid  saturated  with  salt.  In  the  presence  of  only 
protalbumose,  the  urine  gives  Heller's  test,  is  j)recipitated  even  in  neutral 
solution  on  saturating  with  IS'aOl,  but  does  not  coagulate  on  boiling.  The 
presence  of  heteroalbumose  is  shown  by  the  urine  behaving  like  the  above 
with  JS'aCl  and  nitric  acid,  but  shows  a  difference  on  heating.  It  gradually 
becomes  cloudy  on  warming,  and  separates  at  about  G0°  C.  a  sticky  precipi- 
tate which  attaches  itself  to  the  sides  of  the  vessel  and  which  dissolves  at 
boiling  temperature  on  acidifying  the  urine,  and  reappears  on  cooling. 

Quantitative  Estimation  of  Proteid  in  Urine.  Of  all  the  methods 
proposed  thus  far,  the  coagulation  method  (boiling  with  the  addition  of 
acetic  acid)  when  performed  with  sufficient  care  gives  the  best  results. 
The  average  errors  need  never  amount  to  more  than  0.01<^,  and  it  is 
generally  smaller.  In  using  this  method  it  is  best  to  first  find  how  much 
acetic  acid  must  be  added  to  a  small  portion  of  urine,  which  has  been 
previously  heated  on  the  water-bath,  to  completely  separate  the  proteid  so 
that  the  filtrate  does  not  respond  to  Heller's  test.  Then  coagulate^ 
20-50-100  c. c.  of  the  urine.  Pour  the  urine  into  a  beaker  and  heat  on  the 
water-bath,  add  the  required  qaantity  of  acetic  acid  slowly,  stirring  con- 
stantly, and  heat  at  the  same  time.  Filter  while  warm,  wash  first  with 
water,  then  with  alcohol  and  ether,  dry  and  weigh,  incinerate  and  weigh 
again.      In  exact  determinations  the  filtrate  must  not  give  Heller's  test. 

The  separate  estimation  of  globulins  and  albumixs  is  done  by  care- 
fully neutralizing  the  urine  and  precipitating  with  MgSO^  added  to 
saturation  (Hammarsten),  or  simply  by  adding  an  equal  volume  of  a 
saturated  neutral  solution  of  ammonium  sulphate  (Hofmeister  and  Pohl  '). 
The  precipitate  consisting  of  globulin  is  thoroughly  washed  with  a  saturated 
magnesium-sulphate  or  half-saturated  ammonium-sulphate  solution,  dried 
continuously  at  110°  C,  boiled  with  water,  extracted  with  alcohol  and 
ether,  then  dried,  weighed,  ashed,  and  weighed  again.  The  quantity  of 
albumin  is  calculated  as  the  difference  between  the  quantity  of  globulins 
and  the  total  proteids. 

Approximate  Estimation  of  Proteid  in  Urine.  Of  the  methods  sug- 
gested for  this  purpose  none  has  been  more  extensively  employed  than 
Esbacii's. 

Esbacu's^  Method.  The  acidified  urine  (acidified  Avith  acetic  acid)  is 
poured  into  a  specially  graduated  tube  to  a  certain  mark,  and  then  the 
reagent  ( i  2;^  citric-acid  and  1^  picric-acid  solution  in  water)  is  added  to  a 
second  mark,  the  tube  closed  with  a  rubber  stopper  and  carefully  shaken, 
avoiding  the  prodnction  of  froth.     The  tube  is  allowed  to  stand  24  hours, 

'  Haminarsten,  Pflilger's  Arch.,  Bd.  17  ;  Hofmeister  and  Pohl,  Arch.  f.  exp.  Path. 
u.  Pharm.,  Bd.  20. 

"  In  regard  to  the  literature  on  this  method  and  the  numerous  experiments  to  deter- 
mine its  value  see  Huppert-Neubauer,  10.  Autl.,  S.  853. 


NUCLEOALBUMJN  AND  MUCIN  489 

and  tlien  the  height  of  the  precipitate  in  tlie  gradnated  tube  is  read  ofT. 
Tlie  reading  gives  directly  the  quantity  of  proteid  in  1000  parts  of  the 
nrine.  Urines  rich  in  proteid  must  first  be  dihited  witli  water.  The 
results  obtained  by  this  method  are,  liowever,  dependent  upon  the  tempera- 
ture; and  a  dlllereuce  in  temperature  of  5"  to  G.5°  C.  may  in  urines 
containing  a  medium  quantity  of  proteid  cause  an  error  of  0.2-0.3^1^  defi- 
ciency or  excess  (Ciikistexskn"  and  Mygge ').  This  method  is  only  to  be 
used  in  a  room  in  which  the  temperature  may  be  kept  nearly  constant. 
The  directions  for  its  use  accompany  the  apparatus. 

Other  mcthotls  for  tlic  npproxiinjitc  estimation  of  proteid  are  the  optical  methods  of 
Ohkistensen  ami  ^Iygoe,  of  Roueuts  ami  Stolmkow  as  modified  by  Hkandbkro, 
with  Heller's  test,  whicii  has  been  simplilitd  for  practical  purposes  by  Mittkluach. 
The  density  methods  of  Lang,  IIuppert.  and  Zaiiou  arc  also  very  good.  In  roirard  to 
these  and  other  methods  we  refer  to  Huppeht-Neubaueu's  Ham-Analyse,  10   Anil. 

We  have  for  the  present  no  trustworthy  method  for  the  quantitative  estimation  of  al- 
bumoses  ami  peptone  iu  the  urine. 

Xndeoalbiimiii  and  Mxicin.  According  to  K.  J^Iukxer  traces  of  urinary 
mucoid  may  pass  into  solution  in  the  urine;  otherwise  normal  urine  con- 
tains no  mucin.  There  is  no  doubt  that  we  may  have  cases  where  true 
mucin  appears  in  the  urine;  in  most  cases  mucin  has  probably  been 
mistaken  for  so-called  nucleoalbumin.  The  occurrence,  under  some  circum- 
stances, of  nucleoalbumin  in  the  urine  is  not  to  be  denied,  as  such  substances 
occur  in  the  kidneys  and  urinary  passages;  still  in  most  cases  this  nucleo- 
albumin, as  shown  by  K.  Morner,'  is  of  an  entirely  different  kind. 

Every  urine,  according  to  Morxer,  contains  a  little  proteid  and  in 
addition  substances  precipitating  proteid.  If  the  urine  freed  from  salts  by 
dialysis  is  shaken  with  chloroform  after  the  addition  of  1-2  p.  m.  acetic 
acid,  a  precipitate  is  obtained  which  acts  like  a  nucleoalbumin.  If  the  acid 
filtrate  is  treated  with  seralbumin,  a  new  and  similar  precipitate  is  obtained 
due  to  the  presence  of  a  residue  of  the  substance  precipitating  jiroteids. 
The  most  important  of  these  proteid-precipitating  substances  is  chon- 
droitin-sulphuric  acid  and  nucleic  acid,  although  to  a  much  smaller  extent. 
Taurocholic  acid  may  in  a  few  cases,  especially  in  icteric  urines,  be  precipi- 
tated. The  substances  isolated  by  different  investigators  from  urine  by  the 
addition  of  acetic  acid  and  called  "  dissolved  mucin  "  or  "  nucleoajliumin  " 
are  considered  by  Morner  as  a  combination  of  proteid  with  chiefly  chon- 
droitin-sulphuric  acid,  and  to  a  less  extent  with  nucleic  acid,  and  also  perhaps 
with  taurocholic  acid. 

As  normal  urine  habitually  contains  an  excess  of  substance  precipitating 
proteids,  it  is  apparent  that  an  increased  elimination  of  so-called  nucleo- 
albumin may  be  caused  simply  by  an  increased  elimination  of  proteid. 
This  happens  to  a  still  greater  extent  in  cases  where  the  proteid  as  well  as 
the  proteid-precipitating  substance  is  eliminated  to  an  increased  extent. 


'  Chrislensen,  Virchow's  Arch.,  Bd.  115. 
'  Skand.  Arch.  f.  Physiol..  Bd.  6. 


490  URINE. 

Detection  of  so-called  Kucleoalhumijis.  When  a  nrine  becomes  cloudy 
or  precipitated  on  the  addition  of  acetic  acid,  and  when  it  gives  a  more 
typical  reaction  with  Hellee's  test  after  dilution  of  the  urine  than  before, 
one  is  justified  in  making  tests  for  mucin  and  nucleoalbumin.  As  the  salt 
of  the  urine  interferes  considerably  with  the  precipitation  of  these  substances 
by  acetic  acid,  they  must  first  be  removed  by  dialysis.  As  large  a  quantity 
of  urine  as  possible  is  dialyzed  (with  the  addition  of  chloroform)  until  the 
salts  are  removed.  Then  acetic  acid  is  added  until  it  contains  2  p.m.,  and  is 
allowed  to  stand.  The  precipitate  is  dissolved  in  water  by  the  aid  of  the 
smallest  possible  quantity  of  alkali  and  precipitated  again.  In  testing  for 
chondroitin-sulphuric  acid  a  part  is  warmed  on  the  water-bath  with  about  5^ 
hydrochloric  acid.  If  positive  results  are  obtained  on  testing  for  sulphuric 
acid  and  reducing  substance,  then  chondroproteid  was  present.  If  a  reduc- 
ing substance  can  be  detected  but  no  sulphuric  acid,  then  mucin  is  probably 
there.  If  it  does  not  contain  any  sulphuric  acid  or  reducing  substance,  a 
part  of  the  precipitate  is  exposed  to  pepsin  digestion  and  another  part  used 
for  the  determination  of  any  organic  phosphorus.  If  positive  results  are 
obtained  from  these  tests,  then  we  must  differentiate  between  nucleoalbumin 
and  nncleoproteid  by  special  tests  for  nnclein  bases.  No  positive  conclusion 
can  be  drawn  except  by  using  very  large  quantities  of  urine. 

Nudcoliiston.  lu  a  case  of  pseudoleucremia  A.  Jolles  found  a  pliosphorized  protein 
substance  which  he  consiciers  as  identical  with  nucleohiston.  Histon  is  claimed  to  have 
been  ^und  in  some  cases  by  Krehl  and  Matthes  and  by  Kolisch  and  Burian.' 

Blood  and  Blood-coloring  Matters.  The  urine  may  contain  blood  from 
hemorrhage  in  the  kidneys  or  other  parts  of  the  urinary  passages  (hema- 
turia). In  these  cases,  when  the  quantity  of  blood  is  not  very  small,  the 
urine  is  more  or  less  cloudy  and  colored  reddish,  yellowish  red,  dirty  red, 
brownish  red,  or  dark  brown.  In  recent  hemorrhages,  in  which  the  blood 
has  not  decomposed,  the  color  is  nearer  blood-red.  Blood-corpuscles  may 
be  found  in  the  sediment,  sometimes  also  blood-casts  and  smaller  or  larger 
blood-clots. 

In  certain  cases  the  urine  contains  no  blood-corpuscles,  but  only  dis- 
solved blood-coloring  matters,  hsemoglobin  or,  and  indeed  quite  often, 
methaemoglobin  (hemoglobinuria).  The  blood-pigments  appear  in  the 
urine  under  different  conditions,  as  in  dissolution  of  blood  in  poisoning  with 
arseniuretted  hydrogen,  chlorates,  etc.,  after  serious  burns,  after  transfusion 
of  blood,  and  also  in  the  periodic  a2)pearance  of  hsemoglobinuria  with  fever. 
In  hemoglobinuria  the  urine  may  also  have  an  abundant  grayish-brown 
sediment  rich  in  proteid  which  contains  the  remains  of  the  stromata  of  the 
red  blood-corpuscles.  In  animals  hemoglobinuria  may  be  produced  bjr 
many  causes  wliich  force  free  htemoglobin  into  the  plasma. 

To  detect  blood  in  the  urine  we  make  use  of  the  microscope,  spectro- 
scope, the  guaiacum  test,  and  Heller's  or  Heller-Teichmann's  test. 

Microscopic  Investigation.  The  blood-corpuscles  may  remain  undissolved 
for  a  long  time  in  acid  urine;  in  alkaline  urine,  on  the  contrary,  they  are 

'Jolles,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  30;  Krehl  and  Matthes,  Deutsch. 
Arch.  f.  kiln.  Med.,  Bd.  54;  Kolisch  and  Buriau,  Zuitschr.  f.  klin.  Med.,  Bd.  29. 


BLOOD  AND  BLOOD   PIGMENTS.  491 

easily  changed  and  dissolved.  They  often  appear  entirely  unchanged  in  tho 
sediment;  in  some  cases  they  are  distended,  and  in  others  unequally  pointed 
or  jagged  like  a  thorn-apple.  In  hemorrhage  of  the  kidneys  a  cylindrical 
clot  is  sometimes  found  in  the  sediment,  which  is  covered  with  numerous 
red  hlood-corpuscles,  forming  casts  of  the  urinary  passages.  These  forma- 
tions are  called  blood-casts. 

The  spectroscopic  investigation  is  naturally  of  very  great  value;  and  if 
it  he  necessary  to  determine  not  only  the  presence  but  also  the  kind  of 
coloring  matter,  this  method  is  indispensable.  In  regard  to  the  optical 
behavior  of  the  various  blood-pigments  we  must  refer  to  Chapter  VI. 

Gnaiacum  2'cst.  Mix  in  a  test-tube  equal  volumes  of  tincture  of 
guaiacnm  and  old  turpentine  which  has  become  strongly  ozonized  by  the 
action  of  air  under  the  influence  of  light.  To  this  mixture,  which  must  not 
liave  the  slightest  blue  color,  add  the  urine  to  be  tested.  In  the  presence 
of  blood  or  blood- pigments,  first  a  bluish-green  and  then  a  beautiful  blue 
ring  appears  where  the  two  liquids  meet.  On  shaking  the  mixture  it 
becomes  more  or  less  blue.  Normal  urine  or  one  containing  proteid  does 
not  give  this  reaction.  For  the  explanation  of  this  we  must  refer  the  reader 
to  Chapter  YI,  page  142.  Urine  containing  pus,  although  no  blood  is 
present,  gives  a  blue  color  with  these  reagents;  but  in  this  case  the  tincture 
of  guaiacum  alone,  Avithont  turpentine,  is  colored  blue  by  the  urine 
(ViTALi').  This  is  at  least  true  for  a  tincture  that  has  been  exposed  for 
some  time  to  the  action  of  air  and  sunlight.  The  blue  color  produced  by 
pus  diifers  from  that  produced  by  blood-coloring  matters  by  disappearing  on 
heating  the  urine  to  boiling.  A  urine  alkaline  by  decomposition  must  first 
be  made  faintly  acid  before  performing  the  reaction.  The  turpentine 
should  be  kept  exposed  to  sunlight,  while  the  tincture  of  guaiacum  must 
be  kept  in  a  dark  glass  bottle.  These  reagents  to  be  of  use  must  be  con- 
trolled by  a  liquid  containing  blood.  This  test,  it  is  true,  in  positive  results 
is  not  absolutely  decisive,  because  other  bodies  may  give  a  blue  reaction ;  bnt 
when  properly  performed  it  is  so  extremely  delicate  that  when  it  gives 
negative  results  any  other  test  for  blood  is  superfluous. 

IIeller-Teichmaxn's  Test.  If  a  neutral  or  faintly  acid  urine  contain- 
ing blood  is  heated  to  boiling,  we  always  obtain  a*  mottled  precipitate 
consisting  of  proteid  and  hamatin.  If  caustic  soda  is  added  to  the  Ijoiling- 
hot  test,  the  liquid  becomes  clear  and  turns  green  when  examined  in  thin 
layers  (due  to  hwmatin  alkali),  and  a  red  precipitate,  appearing  green  by 
reflected  light,  re-forms,  consisting  of  earthy  phosphates  and  htvmatin. 
This  reaction  is  called  Heller's  blood-test.  If  this  precipitate  is  collected 
after  a  time  on  a  small  filter,  it  may  be  used  for  the  hivmin  test  (see  page 
150).  If  the  precipitate  contains  only  a  little  blood-coloring  matter  with  a 
larger  quantity  of  earthy  phosphates,  then  wash  it  with  dilute  acetic  acid, 

'  See  Maly's  Juhresber.,  Bd.  18. 


492  URINE. 

waicli  dissolves  the  earthy  phosphates,  and  use  the  residue  for  the  prepara- 
tion of  Teichmann's  ht^min  crystals.  If,  on  the  contrary,  the  amount  of 
phosphates  is  very  small,  then  first  add  a  little  CaCl,  solution  to  the  urine» 
heat  to  boiling,  and  add  simultaneously  with  the  caustic  potash  some 
sodium-phosphate  solution.  In  the  presence  of  ouly  very  small  quantities 
of  blood,  first  make  the  nriae  very  faintly  akaline  with  ammonia,  add 
tannic  acid,  acidify  with  acetic  acid,  and  use  the  precipitate  in  the  prepara- 
tion of  the  h^emin  crystals  (Struve'). 

Hsematoporphyrin.  Since  the  occurrence  of  luematoporphyrin  in  the 
urine  in  various  diseases  has  been  made  very  probable  by  several  investi- 
gators, such  as  Neusser,  Stokvis,  MacMujstx,  Le  Nobel,  Eussel, 
CoPEMAijf,  and  others,"  Salkowski  has  positively  shown  the  presence  of 
this  pigment  in  the  urine  after  salphonal  intoxication.  It  was  first  isolated 
in  a  pure  crystalline  state  by  Hammarsten  '  from  the  urine  of  insane 
women  after  sul phonal  intoxication.  According  to  Garrod  and  Saillet  * 
traces  of  htematoporphyrin  (Saillet's  urospectrin)  occur  regularly  in 
normal  urines.  It  is  also  found  in  the  urine  during  different  diseases, 
although  it  only  occurs  in  small  quantities.  It  has  been  found  in  consider-' 
able  quantities  in  the  urine  after  intoxication  with  sulphonal. 

Urine  containing  hsematoporphyrin  is  sometimes  only  slightly  colored, 
while  in  other  cases,  as  for  example  after  the  use  of  sulphonal,  it  is  more  or 
less  deep  red  in  color.  The  color  depends  in  these  last-mentioned  cases,  in 
greatest  part,  not  upon  hsematoporphyrin,  but  upon  other  red  or  reddish- 
brown  pigments  which  have  not  been  sufficiently  studied. 

In  the  detection  of  small  quantities  of  ha3matoporphyrin  proceed  as  sug- 
gested by  Garrod.  Precipitate  the  urine  with  a  10^  caustic-soda  solution 
C20  c.c.  for  every  100  c.c.  urine).  The  phosphate  ^precipitate  containing 
the  pigment  is  dissolved  in  alcohol  hydrochloric  acid  (15-20  c.c.)  and  the 
solution  investigated  by  the  spectroscope.  In  more  exact  investigation 
make  the  solution  alkaline  with  ammonia,  add  enough  acetic  acid  to  dis- 
solve the  phosphate  precipitate,  shake  with  cliloroform,  which  takes  up  the 
pigment,  and  test  tliis  solution  with  the  spectroscope. 

In  the  presence  of  larger  quantities  of  ha3nuitoporphyrin  the  urine  is  first 
precipitated,  according  to  Salkoavski,  with  an  alkline  barium-chloride  solu- 
tion (a  mixture  of  equal  volumes  of  barium-hydrate  solution,  saturated  in 
tlie  cold  and  a  10^  barium-chloride  solution),  or,  according  to  IIammartsen," 
with  a  barium-acetate  solution.     The  washed  precipitate,  which  contains 

'  Zeitschr.  f.  anal.  Cbem.,  Bd.  11. 

'  A  very  complete  index  of  tlic  literature  on  lucmatoporphyrin  in  the  urine  may  he 
found  in  11.  Zoja,  Sti  qualche  pigmento  di  alcune  urine,  etc.,  in  Arch.  Ital.  di  clin. 
Med.,  1893. 

^  Salkowski,  Zeitschr.  f.  physiol.  Chem.,  Bd.  15;  Hammarsten,  Skand.  Arch.  f. 
Physiol.,  Bd.  3. 

■•  Garrod.  Jouni.  of  Physiol.  Vols.  13  (contains  review  of  literature)  and  17  ;  Saillet, 
Revue  de  nu'decine,  Tome  16. 

*  Salkowski,  1.  c;  Hammarsten,  1.  c. 


MELANIN  AND   I' US.  49? 

the  linematoporpliyrin,  i:^  allowed  to  stnnd  some  time  at  tlie  temperature  of 
the  room  witii  alcohol  containin*^  hydrochloric  or  snlphjiric  acid  and  then 
liltereil.  The  liltrate  shows  the  ciiaracteristic  spectrum  of  hiematoporjihyrin 
ill  acid  solution,  and  gives  the  spectrum  of  alkaline  hii'iuatopor])liyrin  after 
•saturation  with  ammonia.  If  the  alcoholic  solution  is  mixed  with  chloro- 
form and  a  large  quantity  of  water  added  and  carefully  shaken,  sometimes 
a  lower  layer  of  chloroform  is  ohtained  which  contains  very  pure  huimato- 
porphyrin,  while  the  upper  layer  of  alcohol  and  water  contains  the  other 
pigments  besides  some  htematoporphyrin. 

Other  metlioils,  which  liave  no  advantage  over  Gakkod's  method,  have  been  sug- 
gested by  liiVA  and  Zoja  as  well  as  Saillet. ' 

IJAUMSTAitK '^  fouud  in  a  case  of  lci)r()sy  two  ciiaracteristic  coloring  matters  in  the 
urine,  "  uronibrohaMuatin  "  and  "  urofuscoboeniatiii,"  which,  as  their  names  indicate, 
seem  to  sUiud  iu  close  relationship  to  the  blood-coloring  matters.  Urorubrohoe matin, 
C«eIIe4N»FeQ03,  ,  contains  iron  and  shows  in  acid  sohUion  an  absorption-band  in  front 
of  D  and  a  broader  one  back  of  T).  In  alkaline  solution  it  shows  four  bands — behind 
1),  at  E,  beyond  F,  and  beliind  (/.  It  is  not  soluble  eiiher  in  water,  alcohol,  ether,  or 
chloroform.  It  gives  a  beautiful  brownish-red  non-dichroitic  liquid  with  alkalies. 
Urofuscohamatiii,  CBelliooNbOort  ,  which  is  free  from  iron,  shows  no  characteristic 
spectrum  ;  it  dissolves  iu  alkalies,  producing  a  brown  color.  It  remains  to  be  proved 
■whether  these  two  pigments  are  related  to  (im]nne)  hajmatoporphyrin. 

Melanin.  In  the  presence  of  melanotic  cancers  dark  pigments  are  sometimes  elim- 
inated with  the  urine.  K.  ^Iouxeu  has  isolated  two  pigments  from  such  a  urine,  of 
which  one  was  soluble  in  warm  50-75^  acetic  acid,  and  the  other,  on  the  contrary,  was 
insoluble.  The  one  seemed  to  be  phymatorhiisin  (see  Chapter  XVI).  Usually  the  urine 
does  uot  contain  any  melanin,  but  a  chromogeu  of  melanin,  a  melanogen.  In  such 
cases  the  urine  gives  Eiselt's  reaction,  becoming  dark-colored  with  oxidizing  agents 
such  as  concentrate  nitric  acid,  potassium  bichromate  and  sulphuric  acid,  as  well  as 
with  free  sulphuric  acid.  Urine  containing  melanin  or  melanogen  is  colored  black  by 
ferric-chloride  solution  (v.  Jaksch  ^). 

TJrorosein,  so  named  by  Nencki,^  is  a  urinary  coloring  matter  occurring  in  various 
diseases,  but  which  is  not  a  constituent  of  nornuil  urine.  The  pigment  does  not  occur 
preformed  in  the  urine,  but  first  makes  its  appearance  after  the  addition  of  mineral  acids. 
It  is  readily  soluble  in  water,  dilute  mineral  acids,  ethyl  and  amyl  alcohol.  It  is 
removed  from  the  acid  urine  by  shaking  with  amyl  alcohol.  It  differs  from  indigo-red 
in  the  following  :  Alkalies  immediately  decolorize  a  urorosein  solution,  l)ul  not  an  indigo- 
red  solution.  Urorosein  is  removed  from  itsamyl-alcohol  solution,  by  shaking  with 
ililute  alkali,  while  indigo-red  is  not.  If  the  acid  urine  is  shaken  with  chloroform, 
indigo-red  is  taken  up,  but  not  tirorosein.  Urorosein  is  soon  decompo.sed  by  light  and 
shows  a  sharply  defined  absorption -band  between  7>  and  E.  The  red  pigment  appear- 
ing in  urines  rich  in  skatol  after  the  addition  of  hydrochloric  acid  differs  from  urorosein 
b}'  being  insoluble  in  water,  but  being  readily  soluble  in  ether  and  chloroform. 

Pus  occurs  in  the  urine  in  different  inflammatory  affections,  especially 
in  catarrh  of  the  bladder  and  in  inflammation  of  the  jielvis  of  the  kidneys  or 
the  urethra. 

Pi(S  is  best  detected  Dy  means  of  the  microscope.  The  jius-cells  are 
rather  easily  destroyed  in  alkaline  urines.  In  detecting  pus  we  make  use 
of  Donxe's  pus-test,  which  is  performed  in  the  following  way:  Pour  o.^  the 
urine  from  the  sediment  as  carefully  as  possible,  jilace  a  small  piece  of 
caustic  alkali  on  the  sediment,  and  stir.  If  the  pus-cells  have  not  been 
previously  changed,  the  sediment  is  converted  by  this  means  into  a  slimy 
tough  mass. 


'  Riva  and  Zoja,  Maly's  Jahresber.,  Bd.  24  ;  Saillet,  1.  c. 

'  Pfliiger's  Arch.,  Bd.  9. 

'  K.  Morncr,  Zeitschr.  f.  physiol.  Chem.,  Bd.  11  ;  v.  Jaksch,  ibid.,  Bd.  13. 

*  Nencki  and  Sieber.  Journ.  f.  prakt,  Chem.  (N.  F. ),  Bd.  26. 


494  URINE. 

The  pns-corpuscles  swell  up  in  alkaline  urines,  dissolve,  or  at  least  are- 
so  changed  that  they  cannot  be  recognized  under  the  microscope.  The 
urine  in  these  cases  is  more  or  less  slimy  or  fibrous,  and  it  is  precipitated  in 
large  flakes  by  acetic  acid,  so  that  it  may  possibly  be  mistaken  for  mucin. 
The  closer  investigation  of  the  precipitate  produced  by  acetic  acid,  and 
especially  the  appearance  or  non-appearance  of  a  reducing  substance  after 
boiling  it  with  a  mineral  acid,  demonstrates  the  nature  of  the  precipitated 
substance.     Urine  containing  pus  always  contains  proteid. 

Bile-acids.  The  reports  in  regard  to  the  occurrence  of  bile-acids 
in  the  urine  under  physiological  conditions  do  not  agree.  According  to 
Dragendorff  and  Hone  traces  of  bile-acids  occur  in  the  urine;  according 
to  Mackay  and  v.  Udranszky  and  K.  Moener'  they  do  not.  Patho- 
logically they  are  present  in  the  urine  in  hepatogenic  icterus,  although  not 
invariably. 

Detection  of  Bile-acids  in  the  Urine.  Pettenkofer's  test  gives  the  most 
decisive  reaction;  but  as  it  gives  similar  color  reactions  with  other  bodies,  it 
must  be  supjolemented  by  the  spectroscopic  investigation.  The  direct  test 
for  bile-acids  is  easy  after  the  addition  of  traces  of  bile  to  a  normal  urine. 
But  the  direct  detection  in  a  colored  icteric  urine  is  more  difficult  and  gives 
very  misleading  results;  the  bile-acid  must  therefore  always  be  isolated  from 
the  urine.  Tliis  may  be  done  by  the  following  method  of  Hoppe-Seyler, 
which  is  slightly  modified  in  non-essential  points. 

Hoppe-Seyler's  Method.  Concentrate  the  urine,  and  extract  the 
residue  with  strong  alcohol.  The  filtrate  is  freed  from  alcohol  by  evap- 
oration and  then  precipitated  by  basic  lead  acetate  and  ammonia.  The 
washed  precipitate  is  treated  with  boiling  alcohol,  filtered  hot,  the  filtrate 
treated  with  a  few  drops  of  soda  solution,  and  evaporated  to  dryness.  The 
dry  residue  is  extracted  with  absolute  alcohol,  filtered,  and  an  excess  of 
ether  added.  The  amorphous  or,  after  a  longer  time,  crystalline  precipitate 
consisting  of  alkali  salts  of  the  biliary  acids  is  used  in  performing  Petten- 
kofer's  test. 

Bile-coloring  matters  occur  in  the  urine  in  different  forms  of  icterus. 
A  urine  containing  bile-pigments  is  always  abnormally  colored — yellow,, 
yellowish  brown,  deep  brown,  greenish  yellow,  greenish  brown,  or  nearly 
pure  green.  On  shaking  it  froths,  and  the  bubbles  are  yellow  or  yellowish 
green  in  color.  As  a  rule  icteric  urine  is  somewhat  cloudy,  and  the  sedi- 
ment is  frequently,  especially  when  it  contains  epithelium-cells,  rather 
strongly  colored  by  the  bile-pigments.  In  regard  to  the  occurrence  of 
urojilin  in  icteric  urine  see  page  45G. 

Detection  of  Bile-colorioig  Matters  in  Urine.  Many  tests  have  been  pro- 
posed for  the  detection  of  bile-coloring  matters.  Ordinarily  we  obtain  the 
best  results  either  with  Gmelin's  or  Avith  IIuppert's  test. 

Gmelin's  test  may  be  applied  directly  to  the  urine  ;  but  it  is  better  to 
use  PtOSENBAcn's  modification.  Through  a  very  small  filter  filter  the 
nrine,  which  is  deep-colored  from  the  retained  epithelium-cells  and  bodies 

'  Cited  from  Huppert-Neubauer,  Ham-Analyse,  10.  Aufl.,  S.  229. 


BILE  PIGMENTS.  495 

of  that  nature.  After  the  liquid  lias  entirely  passed  through  apply  to  the 
inside  of  the  filter  a  drop  of  nitric  acid  wiiicli  contains  only  very  little 
nitrous  acid.  A  pale-yellow  spot  will  be  formed  which  is  surrounded  by 
colored  rings  which  appear  yellowish  red,  violet,  blue,  and  green  from 
within  outward.  This  modification  is  very  delicate,  and  it  is  hardly  jiossi- 
ble  to  mistake  iiulicau  and  other  coloring  matters  for  the  bile-j)igments. 
Several  other  modifications  of  Gmelin's  direct  test,  e.g.,  with  concentrated 
sulphuric  acid  and  nitrate,  etc.,  have  been  proposed,  but  they  are  neither 
simpler  nor  more  delicate  than  Kosenbacii's  modification. 

Hlpfert's  Reaction.  In  a  dark-colored  urine  or  one  rich  in  indican 
we  do  not  always  obtain  good  results  with  Gmelin's  test.  In  such  cases, 
as  also  in  urines  containing  blood-coloring  matters  at  the  same  time,  the 
urine  is  treated  with  lime-water,  or  first  with  some  CaCl,  solution,  and  then 
with  a  solution  of  soda  or  ammonium  carbonate.  The  precipitate  which 
contains  the  bile-coloring  matters  is  filtered,  washed,  dissolved  in  alcohol 
which  contains  5  c.c.  concentrated  hydrochloric  acid  in  100  c.c.  (I.  Munk  ^), 
and  heated  to  boiling  when  the  solution  becomes  green  or  bluish-green. 

IIammarsten's  Reaction.  For  ordinary  cases  it  is  sufficient  to  add  a  few 
drops  of  the  urine  to  about  2-3  c.c.  of  the  reagent  (see  page  235),  when  the 
mixture  immediately  after  shaking  turns  a  beautiful  green  or  bluish  green, 
which  remains  for  several  days.  In  tlie  presence  of  only  very  small  quan- 
tities of  bile-pigments,  especially  with  blood  or  other  pigments  at  the  same 
time,  pour  about  10  c.c.  of  the  acid  or  nearly  neutral  (not  alkaline)  urine 
into  the  tube  of  a  small  centrifugal  machine,  and  add  l>aCl,  solution  and  cen- 
trifuge for  about  one  minute.  The  liquid  is  decanted  off  and  the  sediment 
stirred  with  about  1  c.c.  of  the  reagent  and  centrifuged  again.  A  beautiful 
green  solution  is  obtained,  which  may  be  changed  by  the  addition  of  in- 
creased quantities  of  the  acid  mixture  to  blue,  violet,  red,  and  reddish  yel- 
low. Tiie  green  color  may  be  obtained  in  the  presence  of  1  part  bile-pig- 
ment in  500,000-1,000,000  parts  urine.  In  the  presence  of  large  amounts 
of  other  pigments  calcium  cldoride  is  better  suited  than  barium  chloride. 

The  very  delicate  reaction  as  suggested  by  Jolles  is  unfortunately  not 
serviceable  on  account  of  the  formation  of  froth,  especially  in  the  in-esence  of 
proteid  and  blood-pigments. 

Stokvis's  reaction  is  especially  valuable  as  a  control  test  in  those  cases 
in  which  the  urine  contains  only  very  little  bile-coloring  matter  together  with 
larger  quantities  of  other  coloring  matters.  The  test  is  performed  as  fol- 
lows: 20-30  c.c.  urine  is  treated  with  5-10  c.c.  of  a  solution  of  zinc  ace- 
tate (1:5).  The  precipitate  is  washed  on  a  small  filter  with  water  and  then 
dissolved  in  a  little  ammonia.  The  new  filtrate  gives,  either  directly  or  after 
it  has  stood  a  short  time  in  the  air  until  it  has  a  peculiar  brownish-green 
color,  the  absorption-bands  of  bilicyanin  (see  page  235).  This  reaction  is 
unfortunately  not  sufficiently  delicate. 

Many  other  reactions  for  bile-coloring  matters  in  the  urine  have  been 
proposed;  but  as  those  above  mentioned  are  sufficient,  it  is  perhaps  only  nec- 
essary to  give  here  a  few  of  the  other  reactions,  without  entering  into  details. 

Ui.tzmann's  reaction  consists  in  treating  about  10  c.  c.  of  the  urine  ^viih  3-4  c.  c. 
concentrated  caustic-potash  solution  and  then  acidifying  with  hydrochloric  acid.  The 
urine  will  become  a  Ixautiful  green. 

Smith's  Reaction.     Pour  carefully  over  the  urine  tincture  of  iodine,  whereby  a  green 

•  Du  Bois-Reymond's  Arch.,  1898. 


496  URINE. 

rino-  appears  between  the  two  liquids.'    You  may  also  shake  the  urine  with  tincture  of 
iodme  until  it  has  a  green  color. 

Ehulich's  I'est.  First  mix  the  urine  with  an  equal  volume  of  dilute  acetic  acid  and 
then  add  drop  by  drop  a  solution  of  sulpbo-diazobenzol.  The  acid  mixture  becomes 
dark  red  in  the  presence  of  bilirubin,  and  this  color  becomes  bluish  violet  on  the  addi- 
tion of  glacial  acetic  acid.  The  sulpho-diazobenzol  is  prepared  with  1  grra.  sulphanilic  ■ 
acid,  15  c.  c.  hydrochloric  acid,  and  0.1  grm.  sodium  nltrile  ;  this  solution  is  diluted  to 
1  litre  with  water. 

JMedicinal.  coloring  matters  produced  from  santonin,  rhubarb,  senna,  etc.,  may 
give  an  abnormal  color  to  the  urine  which  may  be  mistaken  for  bile-coloring  matters  or, 
in  alkaline  urines,  perhaps  for  blood-coloring  matters.  If  hydrochloric  acid  is  added  to 
such  a  urine,  it  becomes  yellow  or  pale  yellow,  while  on  the  addition  of  an  excess  of 
alkali  it  becomes  a  more  or  less  beautiful  red. 

Sugar  in  TTrine. 

The  occurrence  of  traces  of  grajie-sugar  in  the  urine  of  perfectly  healthy 
persons  has  been,  as  above  stated  (page  459),  quite  positively  proved.  If 
sugar  appears  in  the  urine  in  constant  and  especially  in  large  quantities,  it 
must  be  considered  as  an  abnormal  constituent.  We  have  given  in  a  pre- 
vious chapter  several  of  the  jorincipal  causes  of  glycosuria  in  man  and 
animals,  and  we  refer  the  reader  to  Chapters  VIII  and  IX  for  the  essential 
facts  in  regard  to  the  appearance  of  sugar  in  the  urine. 

Jin  man  the  appearance  of  glucose  in  the  urine  has  been  observed 
under  various  pathological  conditions,  such  as  lesions  of  the  brain  and 
especially  of  the  medulla  oblongata,  abnormal  circulation  in  the  abdomen, 
diseases  of  the  heart,  lungs,  and  liver,  cholera,  and  many  other  diseases. 
The  continued  j^resence  of  sugar  in  human  urine,  sometimes  in  very 
considerable  quantities,  occurs  in  diabetes  mellitus.  In  this  disease 
there  may  be  an  elimination  of  1  kilogramme  or  even  more  of  grape- 
sugar  per  day.  In  the  beginning  of  the  disease,  when  the  quantity 
of  sugar  is  still  very  small,  the  urine  often  does  not  appear  abnormal. 
In  more  developed,  typical  cases  the  quantity  of  urine  voided  increases 
considerably,  to  3-6-10  litres  per  day.  The  percentage  of  the  physi- 
ological constituents  is  as  a  rule  very  low,  while  their  absolute  daily 
quantity  is  increased.  The  urine  is  pale,  but  of  a  high  specific  gravity, 
1.030-1.040  or  even  higher.  The  high  specific  gravity  depends  upon  the 
quantity  of  sugar  present, — which  varies  in  different  cases,  but  may  be  as 
high  as  10^.  The  urine  is  therefore  characterized  in  typical  cases  of  dia- 
betes by  the  very  large  quantity  voided,  by  the  pale  color  and  high  specific 
gravity,  and  by  its  containing  sugar. 

That  the  urine  after  the  introduction  of  certain  medicines  or  poisonous 
bodies  into  the  system  contains  reducing  bodies,  conjugated  glycuronic 
acids,  which  may  be  mistaken  for  sugar,  has  already  been  mentioned. 

The  properties  and  reactions  of  glucose  have  been  treated  of  in  a  pre- 
vious chapter,  and  it  remains  but  to  mention  the  methods  of  detecting  and 
quantitatively  determining  glucose  in  the  urine. 


SUOAR.  497 

7  he  detection  of  sugar  in  tho  urine  is  ordinarily,  in  the  presence  of  not 
too  small  quantities  of  sugar,  a  very  simple  task.  The  presence  of  only  very 
small  quantities  may  make  its  detection  sometimes  very  difficult  and  labori- 
ous. A  urine  containing  protcid  must  first  have  the  proteid  removed  by 
coagulation  with  acetic  acid  and  heat  before  it  can  be  tested  for  sugar. 

The  tests  which  are  most  frequently  employed  and  are  especially  recom- 
mended arc  as  follows: 

Trommer's  Test.  In  a  typical  diabetic  urine  or  one  rich  in  sugar  this 
test  succeeds  well,  and  it  may  be  performed  in  the  manner  suggested  on 
page  81.  This  test  may  lead  to  very  great  mistakes  in  urines  poor  in  sugar, 
especially  when  they  have  at  the  same  time  normal  or  increased  amounts  of 
physiological  constituents,  and  therefore  it  cannot  be  recommended  to  phy- 
sicians or  to  persons  inexperienced  in  such  work.  Normal  urine  contains 
reducing  substances,  such  as  uric  acid,  creatinin,  and  others,  and  therefore 
a  reduction  takes  place  with  all  urine  on  using  this  test.  We  do  not  generally 
have  a  separation  of  copper  suboxide,  but  still  if  we  vary  the  proportion  of 
the  alkali  to  tlie  copper  sulphate  and  boil,  we  often  have  an  actual  separation 
of  suboxide  in  normal  urines,  or  we  obtain  a  peculiar  yellowish-red  liquid 
due  to  finely  divided  hydrated  suboxide.  This  occurs  especially  on  the  addi- 
tion of  much  alkali  or  too  much  copper  sulphate,  and  by  careless  manipula- 
tion the  inexperienced  worker  may  therefore  sometimes  obtain  apparently 
positive  results  in  a  normal  urine.  On  the  other  hand,  as  urine  contains 
substances,  such  as  creatinin  and  ammonia  (from  the  urea),  which  in  the 
presence  of  only  little  sugar  may  keep  the  copper  suboxide  in  solution,  he 
may  easily  overlook  small  quantities  of  sugar  that  may  be  present. 

Trommer's  test  may  of  course  be  made  positive  and  useful,  even  in  the 
presence  of  very  small  quantities  of  sugar,  by  using  the  modification 
suggested  by  Worm  Muller.  As  this  modification  is  rather  complicated 
and  requires  much  practice  and  exactness,  it  is  probably  rarely  employed  by 
the  busy  physician.     The  following  test  is  to  be  preferred. 

Almen's  bismuth  test,  which  recently  has  been  incorrectly  called 
Nylander's  test,  is  performed  witii  tlie  alkaline  bismuth  solution  prepared 
as  above  described  (page  81).  For  each  test  10  c.c.  of  urine  is  taken  and 
treated  with  1  c.c.  of  the  bismuth  solution  and  boiled  for  a  few  minutes. 
In  the  presence  of  sugar  the  urine  becomes  darker  yellow  or  yellowish 
brown.  Then  it  grows  darker,  cloudy,  dark  brown,  or  nearly  black,  and 
non-transparent.  After  a  longer  or  shorter  time  a  black  deposit  u])pears, 
the  supernatant  liquid  gradually  clears,  but  still  remains  colored.  In  the 
presence  of  only  very  little  sugar  the  test  is  not  black  or  dark  brown,  but 
simply  deeper-colored,  and  not  until  after  some  time  do  we  see  on  the  upper 
layer  of  the  phosphate  precipitate  a  dark  or  black  edge  (of  bismuth  ?). 
In  the  presence  of  much  sugar  a  larger  amount  of  reagent  may  be  used 
without  disadvantage.  In  a  urine  poor  in  sugar  we  must  use  only  1  c.c.  of 
the  reagCTit  for  every  10  c.c.  of  the  urine. 

This  test  shows  the  presence  of  0.5  p.  m.  sugar  in  the  urine.  The 
sources  of  error  which  interfere  in  Trommer's  test,  such  as  the  presence  of 
iiric  acid  and  creatinin,  entirely  disappear  in  this  test.  The  bismuth  test 
is,  besides,  more  easily  performed,  and  it  is  therefore  to  be  recommended  to 
the  physician.  Small  quantities  of  proteid  do  not  interfere  with  this  test; 
large  quantities  nuiy  give  rise  to  an  error  by  forming  bismuth  sulphide,  and 
therefore  must  be  removed  by  coagulation. 


498  UBINE. 

In  using  this  method  it  must  not  be  overlooked  that  it  is,  like  Trommer^s 
test,  a  reduction  test,  and  it  consequently  may  show,  besides  sugar,  certain 
other  reducing  substances.  Such  bodies  are  various  conjugated  glycuronic 
acids  which  may  appear  in  the  urine.  Positive  results  have  been  obtained 
Avith  the  bismuth  test  on  urine  after  the  use  of  several  medicines,  such  as 
rhubarb,  senna,  antipyrin,  kairin,  salol,  turi^entine,  and  others.  Prom  this 
it  follows  tliat  we  should  never  be  satisfied  with  this  test  alone,  especially 
when  the  reduction  is  not  very  great.  When  this  test  gives  negative  results 
we  can  consider  the  urine  as  free  from  sugar  from  a  clinical  standpoint,  and 
when  it  gives  jDOsitive  results  other  tests  must  be  applied.  Among  these 
the  fermentation  test  is  of  special  value. 

Fermentation  Test.  On  using  this  test  we  must  proceed  in  various 
ways,  according  as  the  bismuth  test  shows  small  or  large  quantities.  If  a 
rather  strong  reduction  is  obtained,  the  urine  may  be  treated  with  yeast  and 
the  presence  of  sugar  determined  by  the  generation  of  carbon  dioxide. 
In  this  case  the  acid  urine,  or  that  faintly  acidified  with  tartaric  acid,  is 
treated  with  yeast  which  has  previously  been  washed  by  decantation  with 
water.  Pour  this  urine  to  which  the  yeast  has  been  added  into  a 
Schrotter's  gas-burette,  or  glass  tube  with  the  open  end  ground,  close 
with  the  thumb,  and  open  under  the  surface  of  mercury  contained  in 
a  dish.  As  the  fermentation  proceeds,  the  carbon  dioxide  collects  in  the 
upper  part  of  the  tube,  while  a  corresponding  quantity  of  liquid  is  expelled 
bllow.  As  a  control  in  this  case  two  similar  tests  must  be  made,  one 
with  normal  urine  and  yeast  to  learn  the  quantity  of  gas  usually  developed, 
and  the  other  with  a  sugar  solution  and  yeast  to  determine  the  activity  of 
the  yeast. 

If,  on  the  contrary,  we  find  only  a  faint  reduction  with  the  bismuth 
test,  no  positive  conclusion  can  be  drawn  from  the  absence  of  any  carbon 
dioxide  or  the  appearance  of  a  very  insignificant  quantity.  The  urine 
absorbs  considerable  amounts  of  carbon  dioxide,  and  in  the  presence 
of  only  insignificant  quantities  of  sugar  the  fermentation  test  as  above 
performed  may  lead  to  negative  or  inaccurate  results.  In  this  case 
proceed  in  the  following  way:  Treat  the  acid  urine,  or  the  urine  which  has 
been  faintly  acidified  with  tartaric  acid,  with  yeast  whose  activity  has  been 
tested  by  a  special  test  on  a  sugar  solution,  and  allow  it  to  stand  24-48 
hours  at  tlie  temperature  of  the  room,  or,  better,  at  a  little  higher  tem- 
perature. Then  test  again  with  the  bismuth  test,  and  if  the  reaction 
now  gives  negative  results,  then  sugar  was  previously  present.  But  if  the 
reaction  continues  to  give  positive  results,  then  it  shows — if  the  yeast 
is  active — the  presence  of  other  reducing,  unfermentable  bodies.  There 
remains  of  course  the  possibility  that  the  urine  also  contains  some  sugar 
besides  these  bodies.  This  possibility  may  be  determined  by  the  follow- 
ing test: 

P]ic7ijilh]idrnzin  Test.  According  to  v.  Jakscti  this  test  is  performed 
in  the  following  way:  Add  in  a  test-tube  containing  8-10  c.c.  of  the  urine 
two  knife-points  of  phenylliydi'azin  hydrochloride  and  three  knife-points 
sodium  acetate,  and  when  the  added  salts  do  not  dissolve  on  warming  add 
more  water.  The  mixture  is  heated  in  boiling  water,  and  kept  there  for  one 
hour  to  avoid  a. confusion  witli  phenyliiydrazin-glycuronic  acid  (v.  Jaksch 
and  Hirschl).  The  test  is  then  placed  in  a  beaker  full  of  cold  water.  If 
the  quantity  of  sugar  present  is  not  too  small,  a  yellow  crystalline  precipitate 


DETECTION  OF  SUGAR.  499 

is  now  obtained.  If  tlic  precipitate  appears  amorplious,  tliere  arc  found,  on 
looking  at  it  untler  the  microscope,  yellow  needles  singly  and  in  groups.  If 
very  little  sugar  is  ])resent,  pour  the  test  into  a  conical  glass  and  examine 
the  sediment.  In  this  case  at  least  a  few  phenylglucosazone  crystals  are 
found,  while  the  6'ccurrence  of  larger  and  smaller  yellow  plates  or  highly 
refractive  brown  globules  does  not  show  the  presence  of  sugar.  According  to 
y.  jAKScn  this  reaction  is  very  reliable,  and  by  it  the  presence  of  0.3  p.  m. 
sugar  can  be  detected  (Rosenberg,  ({eyer').  In  doubtful  cases  where 
certainty  is  desired,  prepare  the  crystals  from  a  large  cpiantity  of  urine, 
dissolve  them  on  the  filter  by  pouring  over  them  hot  alcohol,  treat  the 
filtrate  with  water,  and  boil  off  the  alcohol.  If  the  characteristic  yellow 
crystalline  needles,  whose  melting-point  (204-205°  C.)  is  also  determined, 
are  now  obtained,  then  this  test  is  decisive  for  the  presence  of  sugar.  It 
must  not  be  forgotten  that  levuloso  gives  the  same  osazone  as  grape-sugar, 
and  that  a  further  investigation  is  necessary  in  certain  cases. 

^J'he  value  of  this  test  has  been  considerably  debated,  and  the  objection 
has  been  made  that  glycuronic  acid  also  gives  a  similar  precipitate.  A  con- 
founding with  glycuronic  acid  is,  according  to  Hirscul,  not  to  be  appre- 
hended when  it  is  not  heated  in  the  water-bath  for  too  short  a  time  (one 
hour).  KiSTERMANN  found  this  precaution  insufficient,  and  Koos  states 
that  the  phenylhydrazin  test  always  gives  a  positive  result  with  human  urine, 
which  coincides  with  E.  Holmgren's"  experience. 

Eubner's  test  is  performed  as  follows:  The  urine  is  precipitated  by  an 
excess  of  a  concentrated  lead-acetate  solution,  and  the  filtrate  carefully 
treated  with  eiiough  ammonia  to  produce  a  floculent  jirecipitatc.  It  is  then 
heated  to  boiling,  when  the  precipitate  becomes  flesh-colored  or  pink  in  the 
presence  of  sugar. 

Polarization.  This  test  is  of  great  value,  especially  as  in  many  cases  it 
quickly  dillereutiates  between  grape-su^ar  and  other  reducing,  Ijevogyrate 
substances,  such  as  conjugated  glycuronic  acid.  In  the  presence  of  only 
very  little  sugar  the  value  of  this  test  depends  on  the  delicacy  of  the  instru- 
ment and  the  dexterity  of  the  observer;  therefore  this  method  is  perhaps 
inferior  in  most  cases  to  the  bismuth  or  the  phenylhydrazin  test. 

If  small  quantities  of  sugar  are  to  be  isolated  from  the  urine,  precipitate 
the  urine  first  with  sugar  of  lead,  filter,  precipitate  the  filtrate  with  am- 
moniacal  basic  lead  acetate,  wash  this  precipitate  with  water,  decompose  it 
with  IIjS  when  suspended  in  water,  concentrate  the  filtrate,  treat  it  with 
strong  alcohol  until  it  is  80  vol.  per  cent,  filter  when  necessary,  and  add 
an  alcoholic  caustic-alkali  solution.  Dissolve  the  precipitate  consisting  of 
saccharates  in  a  little  water,  precipitate  the  potash  by  an  excess  of  tartaric 
acid,  neutralize  the  filtrate  with  calcium  carbonate  in  the  cold,  and  filter. 
The  filtrate  may  be  used  for  testing  with  the  ])olariscope  as  well  as  in  the 
fermentation,  bismuth,  and  phenylhydrazin  tests.  The  presence  of  grape- 
sugar  may  be  detected  by  this  same  process  in  animal  fluids  or  tissues  from 
which  the  proteids  have  been  removed  by  coagulation  or  by  the  addition  of 
alcohol. 

'  V.  Jaksch,  Kliu.  Diagnostik,  4.  Aufl.,  S.  375;  Rosenfeld,  Deutsch.  mtd.  Wocben- 
schr..  18S8  ;  Gcyer,  cited  by  Roos,  Zeitsclir.  f.  physiol.  Clieiii.,  Bd.  15. 

■-'  Ilirschl,  Zeitschr.  f.  pliysiol.  Clieni..  Bd.  14  ;  Kisteiiii:inii,  Dcutscli.  Arch.  f.  klin. 
31cd..  Bd.  50  :  Roos,  1.  c. ;  Uolmgreu,  Maly's  Jabresber.,  Bd.  27. 


500  URINE. 

In  the  isolation  of  sugar  and  carboliydrates  from  the  urine  the  benzoic- 
acid  esters  of  the  same  may  be  prepared  according  to  Baumann's  method. 
The  urine  is  made  alkaline  with  caustic  soda  to  precipitate  the  earthy  phos- 
phates, the  filtrate  treated  with  4  c.c.  benzoyl  chloride  and  40  c.c.  10^ 
caustic-soda  solution  for  every  100  c.c.  of  filtrate,  and  shaken  until  the  odor 
of  benzoyl  chloride  has  disappeared.  After  standing  sufficiently  long  the  ester 
is  collected,  finely  divided,  and  saponified  with  an  alcoholic  solution  of 
sodium  ethylate  in  the  cold  according  to  Baisch's  method/  and  the  various 
carbohydrates  separated  according  to  his  suggestion. 

To  the  physician,  who  naturally  wants  simple  and  quick  methods,  the 
bismutli  test  is  especially  to  be  recommended.  If  this  test  gives  negative 
results,  the  urine  is  to  be  considered  as  free  from  sugar  in  a  clinical  sense. 
If  it  gives  positive  results,  the  presence  of  sugar  must  be  controlled  by 
other  tests,  especially  by  the  fermentation  test. 

Other  tests  for  sugar,  as,  for  example,  the  reaction  with  orthonitrophenylpropiolic 
acid,  picric  acid,  diazobenzol-sulphonic  acid,  are  superfluous.  The  reaction  with  a-uaph- 
thol,  which  is  a  reaction  for  carbohydrates  in  general,  for  glycuronic  acid  and  mucin, 
may,  because  of  its  extreme  delicacy,  give  rise  to  mistakes,  and  is  therefore  not  to  be 
recommended  to  physicians.  Normal  urines  give  this  test,  and  if  the  strongly  diluted 
urine  gives  this  reaction  we  may  suspect  the  presence  of  large  quantities  of  carbohy- 
drates. In  these  cases  we  get  more  positive  results  by  using  other  tests.  This  test  requires 
great  cleanliness,  and  it  has  this  inconvenience,  that  it  is  verydifticult  to  get  sufficiently 
pureyulplniric  acid,  and  sometimes  indeed  perfectly  pure  a-naphthol.  Several  investi- 
gators, such  as  V.  IJdransky,  Lxjther,  Rods  and  Tretjpel,^  have  investigated  this  test 
in  regard  to  its  applicability  as  an  approximate  test  for  carbohydrates  in  the  urine. 

Quantitative  Determination  of  Sugar  in  the  Urine.  The  urine  for  such 
an  estimation  must  first  be  tested  for  proteid,  and  if  any  be  present  it  must 
be  removed  by  coagulation  and  the  addition  of  acetic  acid,  care  being  taken 
not  to  increase  or  diminish  the  original  volume  of  urine.  The  quantity  of 
sugar  may  be  determined  by  titration  with  Fehling's  or  Knapp's  solu- 
tion, by  FERMENTATION,  or  by  POLARIZATION,  and  also  in  other  ways. 

The  titration  liquids  not  only  react  Avith  sugar,  but  also  with  certain 
other  reducing  substances,  and  on  this  account  the  titration  methods  give 
rather  high  results.  AVhcn  large  quantities  of  sugar  are  present,  as  in  typi- 
cal diabetic  urine,  which  generally  contains  a  lower  percentage  of  normal 
reducing  constituents,  this  is  indeed  of  little  account;  but  when  small  quan- 
tities of  sugar  are  present  in  an  otherwise  normal  urine,  the  mistake  may, 
on  the  contrary,  be  important,  as  the  reducing  power  of  normal  urine  may 
correspond  to  5  p.  ni.  grape-sugar  (see  page  460).  In  such  cases  the  titration 
method  must  be  employed  in  connection  with  the  fermentation  method, 
which  will  be  described  later.  It  is  to  be  remarked  that  in  typical  diabetic 
urines  with  considerable  quantities  of  sugar  the  titration  with  Feeling's 
solution  is  just  as  reliable  as  with  Knapp's  solution.  When  the  urine,  on 
the  contrary,  contains  only  little  sugar  with  normal  amounts  of  physiologi- 
cal constituents,  then  the  titration  Avith  Feii ling's  solution  is  more  difficult, 
in  certain  cases  indeed  almost  impossible,  the  results  being  very  uncertain. 
In  such  cases  Knapp's  method  gives  good  results,  according  to  Worm 
MuLLER  and  his  pupils.' 

'  Zeitschr.  f.  physiol.  Chcm.,  Bd.  19. 

'  See  Roos  and  Treupel,  Zeitsclir.  f.  pliysiol.  Cheni.,  lidd.  15  u.  Ifi. 

»  Pfliiger's  Arch.,  Bdd.  16  u.  23  ;  Otto,  .Journid  t.  prakt.  Chem.  (N.  F.),  Bd.  26. 


(QUANTITATIVE  DETERMINATION  OF  SUGAR.  oOl 

The  TITRATION  with  Fkiilixg's  solution  (lepeiuls  on  the  jiowcr  of 
sugar  to  reduce  copper  oxide  in  alkaline  solutions.  For  this  we  formerly 
employed  a  solution  which  contained  a  mixture  of  cop])cr  sulphate,  Rochelle 
salt,  and  sodium  or  ])otassium  hydrate  (Fehlino's  solution);  but  as  such  a 
solution  readily  changes,  we  now  ])repare  a  copper-sulphate  solution  and  an 
alkaline  Ixoehelle-salt  solution  separately,  and  mix  equal  volumes  of  the  two 
solutions  before  using. 

The  concentration  of  the  copper-sulphate  solution  is  such  that  10  c.c.  of 
this  solution  is  reduced  by  0.05  grm.  grape-sugar.  The  copper-sulphate 
solution  contains  34.  Go  grms.  pure,  crystalled,  non-elHorescent  copper  sul- 
])hate  in  1  litre.  The  sulphate  is  crystallized  from  a  hot  saturated  solution 
by  cooling  and  stirring;  and  the  crystals  are  separated  from  the  mother- 
liquor  and  pressed  between  blotting-paper  until  dry.  The  Kochelle-salt 
solution  is  prepared  by  dissolving  173  grms.  of  the  salt  in  350  c.c.  water, 
adding  GOO  c.c  of  a  caustic-soda  solution  of  a  specific  gravity  of  1.12,  and 
diluting  with  water  to  1  litre.  According  to  "Worm  Muller,  these  three 
liquids — Kochelle-salt  solution,  caustic  soda,  and  water — should  be  separately 
boiled  before  mixing  together.  For  each  titration  mix  in  a  small  flask  or 
porcelain  dish  exactly  10  c.c.  of  the  copper-sulphate  solution  and  10  c.c.  of 
the  alkaline  Kochelle-salt  solution  and  add  30  c.c.  water. 

The  urine,  free  from  proteid,  is  diluted  before  the  titration  with  water  so 
that  10  c.c,  of  the  copper  solution  requires  between  5  and  10  c.c.  of  the 
diluted  urine,  which  corresponds  to  between  1^  and  -h^  sugar.  A  urine  of  a 
specific  gravity  of  1.030  may  be  diluted  five  times;  one  more  concentrated, 
ten  times.  The  urine  so  diluted  is  poured  into  a  burette  and  allowed  to  flow 
into  the  boiling  copper-sulphate  and  Kochelle-salt  solution  until  the  copper 
oxide  is  complotly  reduced.  This  has  taken  jdace  when,  immediately  after 
boiling,  the  i)lue  color  of  the  solution  diappears.  It  is  very  ditlicult  and  re- 
quires some  practice  to  exactly  determine  this  point,  especially  when  the 
copper  suboxide  settles  with  difficulty.  To  determine  whether  the  color  has 
disappeared,  allow  the  copper  suboxide  to  settle  a  little  below  the  meniscus 
formed  by  the  surface  of  the  liquid.  If  this  layer  is  not  blue,  the  operation 
is  repeated,  adding  0.1  c.c.  le^  of  urine;  and  if,  after  the  cop})er  suboxide 
has  settled,  the  liquid  has  a  blue  color,  the  titration  may  be  considered  as 
completed.  Because  of  the  difficulty  in  obtaining  tliis  point  exactly,  another 
end-reaction  has  been  suggested.  This  consists  in  filtering  immediately 
after  boiling  a  small  portion  of  the  treated  urine  through  a  small  filter  into 
a  test-tube  which  contains  a  little  acetic  acid  and  a  few  drops  of  potassium- 
ferrocyanide  solution  and  water.  The  smallest  quantity  of  copper  is  shown 
by  a  red  coloration.  If  the  operation  is  quickly  conducted  so  that  no  oxi- 
dation of  the  suboxide  into  oxide  takes  place,  this  end-reaction  is  of  value 
for  urines  which  are  rich  in  sugar  and  poor  in  urea  and  which  have  been 
strongly  diluted  with  water.  In  urines  poor  in  sugar  which  contain  the 
normal  amount  of  urea  and  which  have  not  been  strongly  diluted,  a  con- 
siderable quantity  of  ammonia  may  be  formed  from  the  urea  on  boiling 
the  alkaline  liquid.  This  ammonia  dissolves  the  suboxide  in  part,  which 
easily  passes  into  oxide  thereby,  and  besides  this  the  dissolved  suboxide 
gives  a  red  color  with  potassium  ferrocyanide.  In  just  those  cases  in  which 
the  titration  is  most  difficult  this  end-reaction  is  the  least  reliable.  Practice 
also  renders  it  unnecessary,  and  it  is  therefore  best  to  depend  simply  upon 
the  appearance  of  the  liquid. 


502  URINE. 

To  facilitate  the  settling  of  the  copjier  suboxide  aud  thereby  clearing  the 
liquid.  j\luxK  '  has  lately  suggested  the  addition  of  a  little  calcium-chloride 
solution  and  boiling  again.  A  preciiaitate  of  calcium  tartrate  is  produced 
which  carries  down  the  suspended  copper  suboxide  with  it,  and  the  color  of 
the  liquid  can  then  be  better  seen.  This  artifice  succeeds  in  many  cases, 
but  unfortunately  there  are  urines  m  which  the  titi'ation  with  Feiiling's 
solution  in  no  way  gives  exact  results.  In  those  c:ises  in  which  only  small 
quantities  of  sugar  exist  in  a  urine  rich  in  physiological  constituents  it  is 
best  to  dissolve  a  very  exactly  weighed  quantity  of  pure  dextrose  or  dextrose- 
sodium  chloride  in  the  urine.  The  urine  can  now  be  strongly  diluted  with 
water  and  the  titration  is  successful.  The  difference  between  the  added 
sugar  and  that  found  by  titration  gives  the  reducing  power  of  the  original 
urine  calculated  as  dextrose. 

The  necessary  conditions  for  the  success  of  the  titration  under  all  cir- 
cumstances are,  according  to  SoxHLET,Hhe  following:  The  copper-sulphate 
and  Eochelle-salt  solution  must,  as  above,  be  diluted  to  50  cc.  with  water; 
the  urine  should  contain  only  between  0.5^  and  \fo  sugar,  and  the  total  quan- 
tity of  urine  required  for  the  reduction  must  be  added  to  the  titration  liquid 
at  once  and  boiled  with  it.  From  this  last  condition  it  follows  that  the 
titration  is  dependent  upon  minute  details,  and  several  titrations  are  required 
for  each  determination. 

It  is  best  to  give  here  an  example  of  the  titration.  The  proper  amount 
of /COj^per-sulphate  and  Eochelle-salt  solution  and  water  (total  volume  =  50 
c.c.)  is  heated  to  boiling  in  a  flask;  the  color  must  remain  blue.  The  urine 
diluted  five  times  is  noAv  added  to  the  boiling-hot  liquid,  1  c.c.  at  a  time; 
.after  e;;ch  addition  of  urine  boil  for  a  few  seconds,  and  look  for  the  appear- 
ance of  the  end-reaction.  If  you  find,  for  example,  that  3  c.c.  is  too  little, 
but  that  4  c.c.  is  too  much  (the  liquid  becoming  yellowish),  then  the  urine 
has  not  been  sufficiently  diluted,  for  it  should  require  between  5  and  10  c.c. 
of  the  urine  to  produce  the  complete  reduction.  The  urine  is  now  diluted 
ten  times,  and  it  should  require  between  6  and  8  c.c.  for  a  total  I'eduction. 
Now  prepare  for  new  tests,  which  are  boiled  simultaneously  to  save  time, 
and  add  at  one  time  respectively  G,  6-2,  7,  and  1^  c.c.  of  urine.  If  it  is 
found  that  between  6.j  and  7  c.c.  are  necessary  to  produce  the  end-reaction, 
then  make  four  other  tests,  to  which  add  respectively  6.6,  6.7,  6.8,  and  6.9 
c.c.  of  urine.  If  in  this  case  the  liquid  is  still  somewhat  bluish  with  6.7 
c.c.  and  completely  decolorized  with  6.8  c.c,  we  then  consider  the  average 
iigure  6.75  c.c.  as  correct. 

The  calculation  is  simple.  The  6.75  c.c.  used  contains  0.05  grm.  sugar, 
and  the  percentage  of  sugar  in  the  dilute  urine  is  therefore  (6.75  :  0.05  = 

100  :  X  =) =  0.74.     But  as  the  urine  was  diluted  with  ten  times  its 

6.75 

5  X  10 
volume  of  Avater,  the  undiluted  urine  contained —-—;—-  =  7.4^.     The  gen- 

D.75 

5  X  w 
eral  formula  on  using  10  c.c.  copper-sulphate  solution  is  therefore — j — , 

in  which  n  represents  the  number  of  times  the  urine  has  been  diluted,  and  k 
the  number  of  c.c.  used  for  the  titration  of  the  diluted  urine. 

'  Vircbow's  Arch.,  Bd.  105. 

'  Jounml  f.  prakt.  Chem.  (X.  F.),  Bd.  21. 


QUANTITATIVE  DETERMINATION  OF  SUGAli.  503 

Tlic  TITRATION  AccoiiDiNG  TO  Knapp  depends  on  tlie  fact  tliat  mercuric 
■cyanide  in  alkaline  solution  is  reducud  into  metallic  mercury  ])y  gra])e-.sugar. 
The  titration  liquid  should  contain  10  fjrnis.  chemically  })ure  dry  mercuric 
cyanide  and  100  c.c.  caustic-soda  solution  of  a  specific  gravity  ol"  1.145  per 
litre.  When  the  titration  i>s  i)eri"ormed  as  described  below  (according  to 
Worm  ]\1Clli:r  and  Otto),  20  c.c.  of  this  solution  should  correspond  to 
exactly  0.05  grm.  grape-sugar.  If  we  proceed  in  other  ways,  the  value  of 
the  solution  is  dilferent. 

In  this  titration  also  the  quantity  of  sugar  in  the  urine  should  be  between 
^^  and  1^,  and  the  extent  of  dilution  necessary  be  determined  by  a  prelimi- 
luiry  test.  To  determine  the  end-reaction  as  described  below,  the  test  for 
oxcess  of  mercury  is  made  with  sulphuretted  hydrogen. 

In  performing  the  titration  allow  20  c.c.  of  Knapp's  solution  to  flow 
into  a  flask  and  dilute  with  80  c.c.  water  or,  when  you  have  reason  to  tiiink 
that  the  urine  contains  less  than  0.5^  of  sugar,  with  only  40-GO  cc.  After 
this  heat  to  boiling  and  allow  tlie  dilute  urine  to  flow  gradually  into  the  hot 
solution,  at  first  2  c.c,  then  1  c.c,  then  0.5  c.c,  then  0.2  c.c,  and  lastly 
0.1  c.c.  After  each  addition  let  it  boil  4  minute.  When  the  end-reaction 
is  approaching,  the  liquid  begins  to  clarify  and  the  mercury  separates  with 
the  phosphates.  The  end-reaction  is  determined  by  taking  a  drop  of  the 
npper  layer  of  the  liquid  into  a  capillary  tube  and  then  blowing  it  out  on 
pure  white  filter-iiaper.  The  moist  spot  is  first  held  over  a  bottle  contain- 
ing fuming  hydrochloric  acid  and  then  over  strong  sul]:)huretted  hydrogen. 
The  presence  of  a  minimum  quantity  of  mercury  salt  in  the  liquid  is  shown 
by  the  s})ot  becoming  yellowish,  which  is  best  seen  when  it  is  comjtared  with 
a  second  spot  that  has  not  been  ex])osed  to  sulphuretted  liydrogen.  The 
end-reaction  is  still  clearer  when  a  small  part  of  the  liquid  is  filtered,  acidi- 
fied with  acetic  acid,  and  tested  with  sulphuretted  hydrogen  (Otto  ').  The 
calculations  are  just  as  simple  as  .for  the  previous  method. 

This  titration,  unlike  the  previous  one,  may  be  performed  equally  well 
in  daylight  and  in  artificial  light.  Knapp's  method  has  the  following 
advantages  over  Fehling's  method:  It  is  applicable  even  when  the  proi)or- 
tion  of  sugar  in  the  urine  is  very  small  and  that  of  the  other  urinary 
constituents  is  normal.  It  is  more  easily  i)erfornied,  and  the  titration  liquids 
may  be  kept  without  decomjjosing  for  a  long  time  (Worm  J\1ulli:r  and  his 
l)upils'').  The  views  of  different  investigators  on  the  value  of  this  titration 
method  are  somewhat  contradictory. 

Besides  the  above-described  titi'ation  methods  there  are  various  others. 
Thus  Pavy  titrates  with  an  ammoniacal  copper  solution.  K.  B.  Lehmann" 
uses  an  excess  of  copper  salt  and  retitrates  with  potassium  iodide  and 
hyposulphite.  The  sugar  can  also  be  determined  according  to  Alliiin.  and 
esi)ecially  according  to  Pfluger's  modification  of  this  method.* 

Estimation  of  the  Ql^antity  of  Sugar  ry  Fermentation.  This 
may  l)e  done  in  various  ways;  the  simplest  method,  and  one  at  the  same 
time  sufficiently  exact  for  ordinary  cases,  is  that  of  Korerts.  This 
consists  in  determining  the  specific  gravity  of  the  nrine  before  iind  after 

»  Journal  f.  prakt.  Cbem.,  Bd.  26. 
»  Pflili^er's  Arcli.,  Bdd.  16  u.  23. 

'  Lehmiinn,  Arch.  f.  Ilyirierie,   Bd.  30  ;  Pfliiger,  Pfliigci's  Arch.,  Bd.  G6.     In  regard 
to  Pavy's  aud  other  methods  see  Uuppert-Neubaucr,  Ilaru-Aualyse,  10.  Autl. 


504  URINE. 

fermentation.  In  tlic  fermentation  of  sugar,  carbon  dioxide  and  alcohol 
are  formed  as  chief  products  and  the  specific  gravity  is  lowered,  partly  on 
account  of  the  disappearance  of  the  sugar  and  partly  on  account  of  tlie 
production  of  alcohol.  Egberts  found  that  a  decrease  of  0.001  in  the 
specific  gravity  corresponded  to  0.23^  sugar,  and  this  has  been  substan- 
tiated since  by  several  other  investigators  (Worm  Muller  and  others). 
If  the  urine,  for  example,  has  a  specific  gravity  of  1.030  before  fermentation 
and  1.008  after,  then  the  quantity  of  sugar  contained  therein  was  22  X  0.23 
=  5.0G^.. 

In  performing  this  test  the  specific  gravity  must  be  taken  at  the  same 
temperature  before  and  after  the  fermentation.  The  urine  must  be  faintly 
acid,  and  when  necessary  it  should  be  acidified  with  a  little  tartaric-acid 
solution.  The  activity  of  the  yeast  must,  when  necessary,  be  controlled  by 
a  sijecial  test.  Place  200  c.c.  of  the  urine  in  a  400-c.c.  flask  and  add  a  piece 
of  compressed  yeast  the  size  of  a  pea,  and  subdivide  the  yeast  through  the 
liquid  by  shaking,  close  the  flask  with  a  stopper  provided  with  a  finely- 
draAvn-out  glass  tube,  and  allow  the  test  to  stand  at  the  temperature  of  the 
room  or,  still  better,  at  -[-20-25°  0.  After  24-48  hours  the  fermentation 
is  ordinarily  ended,  but  this  must  be  verified  by  the  bismuth  test.  After 
complete  fermentation  filter  through  a  dry  filter,  bring  the  filtrate  to  the 
proper  temperature,  and  determine  the  specific  gravity. 

If ,  the  specific  gravity  be  determined  with  a  good  pycnometer  supplied 
witlya  thermometer  and  an  expansion-tube,  this  method,  when  the  quantity 
of  sugar  is  not  less  than  4-5  p.  m,,  gives,  according  to  Worm  Muller,  very 
exact  results,  but  this  has  been  disputed  by  Budde.^  For  the  physician  the 
method  in  this  form  is  not  quite  serviceable.  Even  when  the  specific  gravity 
is  determined  by  a  delicate  urinometer  which  can  give  the  density  to  the 
fourth  decimal,  we  do  not  obtain  quite  exact  results,  because  of  the  ordinary 
errors  of  the  method  (Budde);  but  the  errors  are  usually  smaller  than  those 
which  occur  in  titrations  made  by  unpractised  hands.  Among  the  methods 
proposed  and  closely  tested  for  the  quantitative  estimation  of  sugar,  we  have 
none  which  are  at  the  same  time  easily  performed  and  which  give  positive 
results  in  other  than  experienced  liands. 

When  the  quantity  of  sugar  is  less  than  5  p.  m.  these  methods  cannot  be 
used.  Such  a  small  quantity  of  sugar  cannot,  as  above  mentioned,  be  de- 
termined by  titration  directly,  because  the  reducing  power  of  normal  urine 
corresponds  to  4-5  p.  m.  In  such  cases,  according  to  Worm  Muller,  first 
determine  the  reduction  power  of  the  urine  by  titration  with  Knapp's  solu- 
tion, then  ferment  the  urine  with  the  addition  of  yeast,  and  titrate  again 
with  KiiAPP's  solution.  The  ditt'erence  found  between  the  two  titrations 
calculated  as  sugar  gives  the  true  quantity  of  the  latter. 

Estimation  of  Sugar  by  Polarization.  In  this  method  the  urine 
must  be  clear,  not  too  deeply  colored,  and,  above  all,  must  not  contain  any 
other  optically  active  substances  besides  glucose,  l^y  using  a  delicate  instru- 
ment and  witli  sufficient  ])ractice  very  exact  results  can  be  obtained  by  this 
method.  For  the  physician  Roberts'  fermentation  test,  which  requires  no 
expensive  apparatus  and  no  special  practice,  is  to  be  joreferred.     Under  such 

'  Roberts,  Edinburgh  Med.  Journ.,  1861,  and  The  Lancet,  Vol.  1,  18G3 ;  Worm 
Muller,  Pfl iigor's  Arcli.,  Bdd.  33  and  87  ;  Budde,  ibid.,  Bd.  40,  and  Zeitschr.  f.  physiol. 
Chem.,  B(l.  13.     See  also  Huppert-Neubaiier. 


LEW  LOSE  AND   MILK  SUGAR.  505 

circumstances,  and  as  the  estimation  by  means  of  polarization  can  be  j)t.r- 
fornicd  witli  exactitude  only  by  si)ocially  trained  chemists,  it  is  hiirdly 
necessary  to  give  this  metiiod  in  detail,  and  the  reader  is  referred  to  hand- 
books for  instructions  in  the  use  of  the  apparatus. 

Levulose.  Lajvogyrate  uiines  containing  sugar  have  l)ec'n  observed  by  Vkntzke, 
ZiMMEU  Jind  CzAVEK,  Seeoen,  and  others.'  The  uaiuie  of  the  substance  causing  tiiis 
action  is  ciilliciilt  to  liesrrihc  exactly,  l)ul  tliere  is  liartlly  any  tioubt  that  tin-  urine,  at 
least  in  certain  cases,  as  in  those  observed  b}'  Sekgen,  contains  levulose.  May  Inis  also 
recently  published  a  case  in  wliich  to  all  apjuarances  leviilose  was  present. 

Levuloseisdetecled  as  follows:  The  urine  is  hcvo-rotaloiy,  and  the  la*  vo- rotatory  sub- 
stance ferments  with  yca^t.  The  urine  gives  the  ordinary  reduction  tesl!^  and  phenyU 
glucosazou.  It  gives  Seliwanoff's  reaction  on  boiling  with  re.sorcin  and  hydrochloric 
acid. 

/^rtiW*;  is  a  substance  named  by  Huppert  and  found  by  Leo*  in  diabetic  urine-!  in 
certain  ca.ses,  and  which  he  considers  as  a  sugar.  It  is  iajvogyrate,  amorphous,  and  has 
no  sweet  taste,  hut  v.nther  a  sharp  and  salty  taste.  Laiose  has  a  reducing  action  on  me- 
tallic o.\ides,  does  not  ferment,  and  gives  a  non-crystalline,  yellowish-brown  oil  with 
pheuylhydrazin.     We  have  no  positive  proof  as  yet  that  this  substance  is  a  sugar. 

3IiLK-sroAR.  The  appearance  of  milk-sugar  in  the  urine  of  jiregnant 
women  was  tirst  shown  by  the  observations  of  De  Sixety  and  F.  IIOF- 
-MEISTER,  and  this  has  been  substantiated  by  other  investigators.'  After 
large  quantities  of  milk-sugar  some  lactose  may  be  found  in  the  urine  (see 
Chapter  IX  on  absorption).  The  passage  of  lactose  into  the  urine  is  called 
lactosuria. 

The  positive  detection  of  milk-sugar  in  the  urine  is  diflBcult,  because  this 
sugar  is,  like  glucose,  dextrogyrate  and  also  gives  the  usual  reduction  tests. 
If  urine  contains  a  dextrogyrate,  non-fermentable  sugar  which  reduces  bis- 
muth solutions,  then  it  is  very  probable  that  it  contains  milk-sugar.  It 
must  be  remarked  that  the  fermentation  test  for  milk-sugar  is,  accord- 
ing to  the  experience  of  Li'SK  and  Voit,^  best  performed  by  using  pure  cul- 
tivated yeast  (saccharomyces  apiculutus).  This  yeast  only  ferments  the 
glucose,  while  it  does  not  decompose  the  milk-sugar.  If,  according  to  VoiT, 
we  perform  Rubxer's  test  and  do  not  heat  to  boiling  but  only  to  80°  C,  the 
color  becomes  yellow  or  brown  in  the  presence  of  milk-sugar,  instead  of  red. 
The  most  positive  means  for  the  detection  of  lactose  is  to  isolate  the  sugar 
from  the  urine.     This  may  be  done  by  the  following  method,  suggested  by 

F.   IIOFMEISTER: 

Precipitate  the  urine  with  sugar  of  lead,  filter,  wash  with  water,  unite  the  (illrate 
and  wash-water,  and  precipitate  with  ammonia.  The  liquid  filtered  frotu  the  preci|>i- 
tate  is  again  precipitated  by  sugar  of  lead  and  ammonia  until  the  last  filtrate  is  ("pticall}- 
inactive.  The  several  precipitates  with  the  exception  of  the  first,  which  contains  no 
sugar,  are  uniteii  and  washed  with  water.  The  washed  precipitate  is  decomposed  in 
the  cold  with  sulphuretted  hydrogen  and  filtered.  The  excess  of  sulphuretted  hydro- 
gen is  driven  off  by  a  current  of  air  ;  the  acids  set  free  are  removed  by  shaking  with 
Silver  oxide.  Now  filter,  remove  the  dissolved  silver  by  sulphuretted  hydrogen,  treat 
with  barium  carbonate  to  unite  with  any  free  acetic  acid  present,  and  concentrate. 
Before  the  evaporated  residue  is  syrupy  it  is  treated  with  90;»  alcohol  until  a  flocculent 
precipitate  is  formed  which  settles  quickly.     The  filtrate  from  this  when  placed  in  a 

'  See  IIuppert-Neubauer,  10.  Autl.,  S.  125. 

»  Virchow's  Arch.,  Bd.  107. 

'  Hofmeister,  Zeitschr.  f.  physiol.  Chem.,  Bd.  1,  which  also  contains  the  pertinent 
literature.     See  also  Lemaire,  ibid.,  Bd.  21. 

•*  Carl  Voit,  Ueber  die  Glycogenbildung  nach  Aufnabme  verscbiedeuer  Zuckcrarten, 
Zeitschr.  f.  Biologic,  Bd.  28. 


506  URINE. 

desiccator  deposits  crystals  of  milk-sugar,  wliicli  are  purified  b}' recrystallization ,  dc- 
coloriziiic;  wiili  animal  charcoal  and  boiliug  with  60-70,'i?  alcohol. 

Pentoses.  Salkowski  aud  Jastuowitz  '  fouud  in  the  urine  of  persons  addicted  to 
the  morphin  lial)it  a  variety  of  sugar  which  was  a  pentose  and  yielded  an  osazone 
which  melted  at  159°  C.  In  testing  for  pentose  we  use  the  test  witl)  phloroglucin  and 
hydrochloric  acid,  but  it  must  be  lemarked  that  the  reddish-violet  color  alone  is  not 
sutiicient,  because  galactose  and  lactose  also  give  a  similar  coloration.  The  presence  of 
pentose  or  glycuronic  acid  can  only  be  considered  as  positive  when  on  spectroscopic 
examination  two  absorption-bauds  between  D  and  £J  are  obtained. 

The  phloroglucin-hydrochloric  acid  test  is  performed  as  follows,  according  to 
ToLLENS."  A  few  cubic  centimetres  of  the  urine  are  mixed  with  an  equal  volume  of 
hydrochloric  acid  of  about  1.19  sp.  gr.  and  treated  with  about  25-30  milligrammes 
phloroglucin,  lieated  over  the  flame  until  a  red  coloration  is  obtained,  and  then  immedi- 
ately examined  with  the  spectroscope.  If  no  bauds  are  seen,  then  heat  to  boiliug  and 
observe  again.  If  the  liquid  becomes  cloudy,  it  is  allowed  to  cool,  the  precipitate  col- 
lected on  a  l]lter,  washed  with  water,  dissolved  iu  alcohol,  and  this  solution  examined  with 
the  spectroscope.     In  the  presence  of  pentoses  on  absorption-band  is  seen  in  the  green. 

To  differentiate  between  pentoses  and  glycuronic  acid,  which  give  the  same  spec- 
trum, we  prepare  the  osazones.  The  melting-point  of  the  pentosazon  lies  at  about 
159-160°  C.  In  a  mixture  of  glucosazoue  and  pentosazone  the  latter  may  be  known,  as 
shown  by  Kulz  and  Vogel,3  b}^  extracting  with  water  at  60°  C,  which  dissolves  the 
pentosazone,  filtering  while  hot  and  allowing  to  cool.  The  pentosazone  separates  on 
cooling. 

Inosit  occurs  in  the  urine  in  albuminuria  and  in  diabetes  mellitus,  but 
only  rarely  and  in  small  quantities.  Inosit  is  also  found  in  the  urine 
after/ excessive  drinking  of  water.  According  to  Hoppe-Seylee''  traces  of 
inosit  occur  in  all  normal  urines. 

In  detecting  inosit  the  proteid  is  first  removed  from  the  urine.  Then  concentrate  the 
urine  on  the  water-bath  to  i  and  precipitate  with  sugar  of  lead.  The  filtrate  is  warmed 
aud  treated  with  basic  lead  acetate  as  long  as  a  precipitate  is  formed.  The  precipitate 
formed  after  24  hours  is  washed  with  water,  suspended  in  water,  and  decomposed  with 
sulphuretted  hydrogen.  A  little  uric  acid  may  separate  fronr  the  fitrate  after  a  short 
lime.  The  liquid  is  filtered,  concentrated  to  a  syrupy  consistency,  and  treated  while 
boiling  with  3-4  vols,  alcohol.  The  precipitate  is  quickly  separated.  After  the  addition 
of  ether  to  the  cooled  filtrate,  crystals  separate  after  a  time,  and  these  are  purified  by 
decolorizatiou  and  recrystallization.  With  these  crystals  perform  the  tests  mentioned  on 
page   341. 

Acetone  and  Diacetic  Acid.  These  bodies,  the  occurrence  in  the  urine 
and  formation  in  the  organism  of  which  have  been  the  subject  of  numerous 
investigations,  especially  by  v.  Jakscii,  were  first  observed  in  urine  in 
diabetes  mellitus  (Peters,  Kaulich,  v.  Jaksch,  Gerhardt  ').  Acetone 
may  give  the  diabetic  urine,  as  well  as  the  expired  air,  the  odor  of  apples  or 
other  fruit.  According  to  v.  Jaksch  and  otliers  acetone  is  a  normal  urinary 
constituent,  though  it  may  occur  only  in  very  small  amounts  (0.01  grm.  in 
24  hours). 

'  Centralbl.  f.  d.  med  Wissensch.,  1892,  Nos.  19  and  33. 

■'  Ber.  d.  deutsch.  chem.  Ge.sellsch.,  Bd.  29,  S.  1304. 

3  Zeitschr.  f.  Biologic,  Bd.  32. 

•*  Haudbuch  d.  phy.siol.  u.  pathol.  chem.  Analyse,  6.  Aufl.,  S.  196. 

*  In  regard  to  the  extensive  literature  on  acetone  and  diacetic  acid  we  refer  the  reader 
to  IIuppert-Neubauer,  Ilarn-Analyse,  10.  Aufl.,  and  v.  Noordeu's  Lehrb.  d.  Pathol,  des 
Stoflfwechsels.     Berlin,  1893. 


ACETONE  AND  D I  ACETIC  ACID.  507 

There  is  no  doubt  that  the  appearance  of  acetone  as  well  as  diacetic  acid 
is  essentially  caused  by  an  increased  destruction  of  proteid.  This  follows 
from  the  very  marked  increase  in  the  elimination  of  acetone  aud  diacetic 
acid  during  inanition  (v.  Jaksch,  Fr.  ^Illlek").  This  stands  also  in  good 
accord  with  the  observations  that  a  considerable  increase  in  the  quantity  of 
acetone  and  diacetic  acid  eliminated  is  observed  in  such  diseases  as  fevers, 
dia})etes,  digestive  disturbances,  mental  diseases  with  abstinence,  cachexia, 
where  the  body-proteid  is  largely  destroyed.  According  to  v.  Xoorden 
and  HoNiGMANN  the  extent  of  acetone  and  diacetic-acid  elimination  is  not 
ilepondent  upon  the  absolute  quantity  of  proteid  metabolized,  but  upon  the 
quantity  of  body-proteid  destroyed;  but  this  view  is  disputed  by  other  inves- 
tigators, such  as  HiRSCHFELD  and  Geelmuydex.  Also,  according  to  Wein- 
TRAUD  and  Palm  A  the  parallelism  between  the  elimination  of  acetone  and 
nitrogen,  as  claimed  by  Wright  (in  diabetics),  does  not  exist.  The  elimina- 
tion of  acetone  does  not  always  increase  with  an  increased  quantity  of  pro- 
teid, and  the  raising  of  the  proteid  above  an  average  point  causes  a  diminu- 
tion in  the  elimination  of  acetone  (Kosenfeld,  Uirsciifeld"). 

The  carbohydrates  have  a  strong  influence  on  the  elimination  of  acetone, 
namely,  the  exclusion  of  carbohydrates  from  the  food,  or  diminishing  their 
amount,  causes  an  increased  elimination,  while  abundance  of  carbohydrates 
decreases  the  quantity  considerably,  or  even  causes  a  disappearance.  Fat 
seems,  by  its  action  on  proteid  metabolism,  to  have  an  indirect  influence  on 
acetonuria.  According  to  Geelmuyden  the  elimination  of  acetone  in  man 
may  be  increased  by  an  increased  consumption  of  fat  (butter),  and  this 
increase  may  run  parallel  with  the  fat  given. 

Irrespective  of  the  physiological  acetonuria  derived  from  the  food,  we 
have  an  increased  elimination  of  acetone,  as  above  stated,  in  many  dis- 
eases, as  also  after  nervous  lesions,  certain  intoxications,  and  after  ad- 
ministration of  plilorhizin  or  exrtipation  of  the  pancreas  (v,  ]Merixg  and 
Minkowski,  Azemar').  In  dogs  with  phlorhizin  diabetes  Geelmuyden  * 
found  a  stronger  acetonuria  in  starvation,  less  witli  proteid  food,  and  still 
less  on  feeding  with  carbohydrates.  Sodium  butyrate  when  introduced  into 
the  stomach  increases  the  acetonuria,  but  when  introduced  subcutaneously 

'  V.  Jaksch,  Ucber  Acctouurie  uud  Dmcelurie.  Berlin,  1885  ;— Fr.  MQller,  Bcricht 
Uber  die  Ergebuisse  des  au  Cetti  ausgeflihrten  Hungervarsucbes.  Berlin,  kliu.  "Wocben- 
scbv.,  1887. 

'  Honigmann,  Zur  Enstebung  des  Acetons  (Dissert.,  Breslau,  1886),  cited  from  v. 
Noorden,  1.  c,  S.  177;  Ilir-cbfeld,  Zeitscbr.  f.  klin.  Med.,  Bd.  28;  Geeluiuyden,  see 
Maly's  Jiibrcsber.,  Bd.  26,  and  Zeitscbr.  f.  pbysiol.  Cbem.,  Bdd.  23  and  26  ;  "Weiutraud. 
Arcb.  f.  exp.  Patb.  u.  Pbarm.,  Bd.  34  ;  Pahna,  Zeitscbr.  f.  Ileilkuude,  Bd.  15  ;  Wrigbt, 
Maly's  Jabresber.,  Bd.  21  ;  Hosenfeld.  Centralbl.  f.  innere  Med.,  Bd.  16. 

^  Azeniar.  "  Acetonurie  experimentale."  Travaux  de  pbysiologie.  1898  (laboratoire 
de  M.  le  professeur  E.  Hedon,  Moiitpellier). 

*  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  26. 


f)08  URINE. 

it  does  not  act  at  all,  or  only  to  a  slight  extent.  His  experiments  do  not 
show  a  sugar  formation  from  fat  in  phlorhizin  diabetes. 

KuMAGAWA  aud  MiURA,^  in  two  series  of  experiments  on  starving 
dogs  after  phlorhizin  poisoning,  compared  the  extent  of  proteid  metabolism 
and  the  formation  of  sugar  with  each  other,  and  they  succeeded  in  exclud- 
ing a  sugar  formation  from  fat.  In  both  series  of  experiments  the  quantity 
of  sugar  eliminated  was  less  than  that  w^hich  was  calculated  from  the 
increased  proteid  destruction  caused  by  the  phlorhizin  poisoning. 

Diacetic  acid  has  not  been  observed  as  a  physiological  constituent  of  the 
urine.  It  occurs  in  the  urine  chiefly  under  the  same  conditions  as  acetone; 
still  we  have  cases  in  which  only  acetone  and  no  diacetic  acid  appears. 
Like  acetone  the  diacetic  acid  occurs  often  in  children,  especially  in  high 
fevers,  acute  exanthema,  etc.  Diacetic  acid  decomposes  readily  into  acetone. 
According  to  Aeaki  °  it  is  probably  produced  as  an  intermediate  product  in 
the  oxidation  of  /5-oxybutyric  acid  in  the  organism.  The  three  bodies  ap- 
pearing in  the  urine,  acetone,  diacetic  acid,  and  oxybutric  acid,  stand  in 
close  relationship  to  each  other. 

Acetone,  dimeth}^  ketone,  C^H^O  or  CO.(CHJ„,  is  a  thin  water-clear 
liquid/boiling  at  56.5°  C.  and  with  a  pleasant  odor  of  fruit.  It  is  lighter 
than  water,  with  which  it  mixes  in  all  joroportions,  also  with  alcohol  and 
ether.     The  most  important  reactions  for  acetone  are  the  following: 

Lieben's  Iodoform  Test.  When  a  watery  solution  of  acetone  is  treated 
with  alkali  aud  then  with  some  iodine-jDotassium-iodide  solution  and  gently 
warmed  a  yellow  precipitate  of  iodoform  is  formed,  which  is  known  by  its 
odor  and  by  the  appearance  of  the  crystals  (six-sided  plates  or  stars)  under 
the  microscope.  This  reaction  is  very  delicate,  but  it  is  not  characteristic 
of  acetone.  Gunnixg's  modification  of  the  iodoform  test  consists  in  using 
an  alcoholic  solution  of  iodine  and  ammonia  instead  of  the  iodine  dissolved  in 
potassium  iodide  and  alkali  hydrate.  In  this  case,  besides  iodoform,  a  black 
precipitate  of  iodide  of  nitrogen  is  formed,  but  this  gradually  disappears 
on  standing,  leaving  the  iodoform  visible.  This  modification  has  the  ad- 
vantage that  it  does  not  give  any  iodoform  with  alcohol.  On  the  other 
hand,  it  is  not  quite  so  delicate,  but  still  it  detects  0.01  milligramme  acetone 
in  1  c.c. 

Rey^told's  mercuric-oxide  test  is  based  on  the  power  of  acetone  to  dis- 
solve freshly  precipitated  IlgO.  A  mercuric-chloride  solution  is  precipi- 
tated by  alcoholic  caustic  potash.  To  this  add  the  liquid  to  be  tested  for 
acetone,  shake  well  and  filter.  In  the  presence  of  acetone  the  filtrate  con- 
tains mercury,  which  may  be  detected  by  ammonium  sulphide.  This  test 
has  about  the  same  delicacy  as  Gunning's  test. 

'  Du  Bois-Reymond's  Arcli.,  1898. 
'  Zeitscbr.  f.  physiol.  Chem.,  Bd.  18. 


ACETONE  AND  DI ACETIC  ACID.  ^09 

Legal's  Sodium-nitroprusside  Test.  If  an  acetone  solution  is  treated 
with  a  few  drops  of  a  freshly  prepared  sodium-nitroprusside  solution,  and 
then  with  caustic-potash  or  soda  solution,  the  lifjuid  is  colored  ruby-red. 
Creatiiiin  gives  the  same  color;  but  if  we  saturate  with  acetic  acid,  tlic 
color  becomes  carmine  or  purplish-red  in  the  presence  of  acetone,  but  yellow 
and  then  gradually  green  and  blue  in  the  presence  of  crcatinin.  AVith  this 
test  ])aracrosol  gives  a  reddish-yellow  color,  which  becomes  light  pink  when 
acidified  witli  acetic  acid  and  cannot  be  mistaken  for  acetone.  If  we  use 
ammonia  instead  of  the  caustic  alkali  (Le  Nobel),  the  reaction  takes  place 
with  acetone  but  not  with  aldehyde. 

Penzolut's  indigo  test  depends  on  the  fact  that  orthonitrobenzaldehyde 

in  alkaline  solution  with  acetone  yields  indigo.     A  warm  saturated  and  then 

cooled  solution  of  the  aldehyde  is  treated  with  the  liquid  to  be  tested  for 

acetone  and  next  with  caustic  soda.     In  the  presence  of  acetone  the  liquid 

first  becomes  yellow,  then  green,  and  lastly  indigo  separates;  and  this  may 

be  dissolved  with  a  blue  color  by  shaking  with  chloroform.     l.G  milligrms. 

acetone  can  be  detected  by  this  test. 

BfiLA  V.  BiTTo's'  reaction  is  based  ou  the  fact  that  on  adding  a  solution  of  n)etadini- 
trobenzol,  made  alkaline  witli  caustic  potash,  to  acetone,  a  violet-red  color  is  produced 
■\vhicli  beconu's  cheny-ied  on  acidifyini,^  with  an  organic  acid  or  metaphosplioric  acid. 
Aldeliyde  gives  a  similar  violet-red  color  which  becomes  yellowish-red  on  acidification. 
Creatinin  does  not  give  this  reaction. 

Diacetic  acid,  or  aceto-acetic  acid,  0,11,0,  or  C,II,O.CII,.COOII.  This 
acid  is  a  colorless,  strongly  acid  liquid  which  mixes  Avith  w^ater,  alcohol,  and 
ether  in  all  proportions.  On  heating  to  boiling  with  water,  and  especially 
with  acids,  this  acid  decomposes  into  carbon  dioxide  and  acetone,  and  there- 
fore gives  the  above-mentioned  reactions  for  acetone.  It  differs  from  acetone 
in  that  it  gives  a  violet-red  or  brownish-red  color  with  a  dilute  ferric-chloride 
solution.  This  color  decreases  even  at  the  ordinary  temperature  Avithin  24 
hours,  and  more  quickly  on  boiling.  It  differs  in  this  from  phenol,  salicylic 
acid,  acetic  acid,  or  sulphocyanides. 

Detection  of  Acetone  and  Diacetic  Acid  in  the  Urine.  Before  testing  for 
acetone  test  for  diacetic  acid,  and  as  this  acid  gradually  decomposes  on  allowing 
the  urine  to  stand,  the  urine  must  be  as  fresh  as  possible.  In  the  presence 
of  diacetic  acid  the  urine  gives  the  so-called  Gerhardt's  reaction,  showing  a 
wine-red  color  on  the  addition  of  a  dilute,  not  too  acid,  ferric-chloride 
solution.  Treat  10-50  c.c.  of  the  urine  with  ferric  chloride  as  long  as  it  gives 
a  precipitate,  filter  the  precipitjite  of  ferric  phos})hate,  and  add  some  more 
ferric  chloride  to  the  filtrate.  In  the  presence  of  the  acid  a  claret-red  color  is 
produced.  After  this  heat  a  second,  similar  portion  of  the  faintly  acid  urine 
to  boiling,  and  repeat  the  test  on  cooling,  which  should  now  give  negative 
results.  A  third  portion  of  urine  is  acidified  with  sulphuric  acid  and 
shaken  with  ether  (which  takes  up  the  acid).  Now  shake  the  removed  ether 
with  a  very  dilute  watery  solution  of  ferric  chloride,  and  the  watery  layer  be- 

'  Annal.  de  Cbem.  u.  Pharm..  Bd.  369. 


510  URINE. 

comes  violet-red  or  claret-red.  The  color  disappears  on  warming.  K.  Moexek 
suggests  that  in  testing  for  diacetic  acid  the  urine  be  treated  with  a  little 
KI  and  Fe„Cl,  in  excess  and  heated.  In  the  presence  of  diacetic  acid  Tery 
irritating  vapors  of  iodoacetone  are  developed.  According  to  v.  Jaksch  ' 
urines  rich  in  acetone  also  give  this  reaction. 

In  the  absence  of  diacetic  acid  the  acetone  may  be  tested  for  directly. 
This  may  be  done  directly  on  the  urine  by  Pei^zgldt's  test.  Tliis  test, 
which  is  only  approximate,  is  of  value  only  when  the  urine  contains  a 
considerable  amount  of  acetone.  For  a  more  accurate  test  we  distil  at  least 
250  c.c.  of  the  urine  faintly  acidified  with  sulphuric  acid,  care  being  taken 
to  have  a  good  condensation.  Most  of  the  acetone  is  contained  in  the  first 
10-20  c.c.  of  the  distillate.  This  distillate  is  tested  for  acetone  by  the  above 
methods."  In  testing  for  acetone  in  the  simultaneous  presence  of  diacetic  acid, 
first  make  the  urine  faintly  alkaline,  and  shake  it  carefully  with  ether  free 
from  alcohol  and  acetone  in  a  separatory  funnel.  The  removed  ether  is 
then  shaken  with  water,  which  takes  up  the  acetone,  and  then  the  watery 
liquid  is  tested. 

The  quantitative  estimation  of  acetone  in  the  urine  is  done  by  converting 
it  first  into  iodoform.  The  urine  is  acidified  with  acetic  acid  (according  to 
HupPERT,  1-2  c.c.  50  per  cent  acetic  acid  for  every  100  c.c.  urine)  and  dis- 
tilled. The  quantity  of  acetone  in  the  distillate  is  best  determined  accord- 
ing to/MESSiNGER's  and  Huppert's  method  by  determining  volumetrically 
the  quantity  of  iodine  used  in  the  formation  of  iodoform.  In  regard  to  this 
method  and  its  execution  we  refer  the  reader  to  IIuppert-Neubauer.' 

y5-0xybutyric  Acid,  CJI^O,  or  CH,OH(OH).CII„COOH.  The  appearance 
of  this  acid  in  the  urine  was  first  positively  sliown  by  Minkowski,  Kulz 
and  Stadelmann". ■*  It  occurs  especially  in  difficult  cases  of  diabetes,  but  it 
has  also  been  observed  in  scarlet  fever  and  in  measles  (Kulz),  in  scurvy 
(Minkowski),  and  in  diseases  of  the  brain  with  abstinence  (KiJLz).  /3-oxj- 
butyric  acid  is  undoubtedly  derived  from  an  abnormal  destruction  of  body- 
proteid,  and  it  therefore  occurs  in  the  urine  in  inanition,  cachexia,  etc. 
/?-oxybutyric  acid  is  accompanied  by  diacetic  acid  in  the  urine,  while  on 
the  other  hand  the  last-mentioned  acid  occurs  in  the  urine  without  the  first. 
/?-oxybutyric  acid  forms  an  odorless  syrup  which  mixes  readily  with 
water,  alcohol,  and  ether.  This  acid  is  optically  active  and  indeed  Isevo- 
gyrate,  and  it  therefore  interferes  with  the  estimation  of  sugar  in  the  urine 
by  means  of  polarization.  It  is  not  precipitated  either  by  basic  lead  acetate 
or  by  ammouical  l>asic  lead  acetate.  On  boiling  with  water,  especially  in 
the  presence  of  a  mineral  acid,  this  acid  decomposes  into  o'-crotonic  acid, 
which  melts  at  71-72°  C,  and  water:  CII,.CII(OH).CH,.COOH  =  11,0 
-\-  CHj.CIi:  Cn.COOII.  It  yields  acetone  on  oxidation  with  a  chromic- 
acid  mixture. 

'  Milrner,  Skand.  Arcl).  f.  Physiol.,  Bd.  5  ;  v.  Jaksch.,  Klin.  Diaguostik,  4.  AuQ. 
^  See  also  Snlkowski,  Pfliiger's  Arch.,  Bd.  56. 

'  L.  c,  p.  7G0,  and  also  Geelinuyden,  Zeilschr.  f.  anal.  Chcm.,  Bd.  35. 
*  Minkowski,  Arch.  f.  exp.  Path.  u.  Plnum.,  Bdd.  18  and  19  ;  Stadelmann,  ibid.,  Bd. 
17  ;  Kulz,  Zeitschr.  f.  Biologie,  Bdd.  20  and  23. 


0X7BVT7HIC  ACID.  511 

Delecfion  of  /3-Oxybictyric  Acid  in  the  Urine.  If  a  urine  is  still  laevo- 
gyrato  after  fermentation  with  yeast,  the  presence  of  oxybutyric  acid  is 
probable.  A  furtlier  test  may  be  made,  according  to  Kllz,  by  evaporating 
the  fermented  urine  to  a  syrup,  and,  after  the  addition  of  an  equal  volume 
of  concentrated  s«li)huric  acid,  distilling  directly  without  cooling,  o'-cro- 
tonic  acid  is  produced  Avhich  distils  over,  and,  after  collecting  in  a  test- 
tube,  crystals,  which  melt  at  -\-  73°  C,  sejiarate  on  cooling.  If  no 
crystals  are  obtained,  then  shake  the  distillate  with  ether,  and  test  the 
melting-point  of  the  residue  obtained  after  evaporating  the  ether  which 
has  been  washed  with  the  Avater.  According  to  Minkoavski  the  acid  may 
he  isolated  as  a  silver  salt.' 

EuRLicn's'  Urine  Test.  jMix  250  c.c.  of  a  sohition  -which  contains  50  c.c.  IICl  and 
I  grni.  sulphanilic  acid  in  one  litre  witli  5  c.c.  of  a  i%  sohition  of  sodium  nitrite  (whicli 
produces  very  little  of  the  active  body,  sulphodiazohenzol).  In  performing  this  test  treat 
the  urine  with  an  equal  volume  of  this  mixture  and  then  supersaturate  witli  ammoniii. 
Normal  urine  will  hecome  yellow  thereby,  or  orange  after  the  addilion  of  ammonia 
(aromatic  oxyacids  may  sometimes  after  a  certain  time  give  red  azo  bodies  which  color 
the  upper  layer  of  phosphate  sediment).  In  pathological  urines  we  sometimis  have 
(and  this  is  the  characteristic  diazo  reaction)  a  primary  yellow  coloration,  with  a  very 
marked  secondary  red  coloration  on  the  addition  of  ammonia,  and  the  froth  is  also  linged 
with  reil.  The  upper  layer  of  the  sediment  becomes  greenish.  The  body  which  gives 
this  reaction  is  unknown,  but  it  occurs  especially  in  the  urine  of  typhoid  patients  (Ehu- 
Licn).     Opinions  differ  in  regard  to  the  siguilicance  of  this  reaction. 

KosENHACn's  urine  test,  which  consists  in  adding  nitric  acid  drop  by  drop  to  the 
boiling-hot  urine  and  obtaining  a  claret-red  coloration  and  a  bluish-red  foam  on  shak- 
ing, depends  upon  the  formation  of  indigo  substances,  especially  indigo-red. ^ 

F<ii  ill  the  Urine.  The  elimination  of  a  urine  which  in  ajipearaiice  and  richness  in 
fat  resembles  chyle  is  called  chyluria.  It  habitually  contains  proteid  anil  often  librin. 
Chyluiia  occurs  mostly  in  the  inhabitants  of  the  tropics.  Lipuria,  or  the  elimination 
of  fat  with  the  uiine,  may  appear  in  apparently  healthy  persons,  sometimes  with  and 
sometimes  without  albiuninuria,  in  pregnane}'',  and  also  in  certain  diseases,  as  in  dia- 
betes, poisoning  with  phosphorus,  and  fatty  degeneration  of  the  kidneys. 

Fat  is  usually  detected  by  the  microscope.  It  may  also  be  dissolved  with  ether,  and 
may  invariably  be  detected  by  evaporating  the  urine  to  dryness  and  extracting  the  residue 
with  ether. 

CJiolesterin  is  also  sometimes  found  in  the  urine  in  chyluria  and  in  a  few  other 
cases. 

Leucin  and  Tyrosin.  These  bodies  are  found  in  the  urine,  especially 
in  acute  yellow  atrophy  of  the  liver,  in  acute  phosphorus-poisoning,  and  in 
severe  cases  of  typhoid  and  smallpox. 

Detection  of  Leucin  and  Tyrosin.  Tyrosin  occurring  as  sediment  may  be  identified 
by  means  of  the  microscope  ;  but  if  a  positive  proof  is  desired,  a  recrystallization  of 
the  same  from  ammonia  or  ammoniacal  alcohol  is  necessary. 

To  detect  both  these  bodies  when  they  occur  in  solution  in  the  urine,  proceed  in 
the  following  munner  :  The  urine  free  from  proteid  is  precipitated  by  liasic  lead  ace- 
tate, the  lead  removed  from  the  filtrate  by  II^S,  and  concentrated  as  nuich  as  pos- 
sible. The  residue  is  extracted  with  a  small  quantity  of  absolute  alcohol  to  remove 
the  urea.  The  i^sidue  is  then  boiled  with  faintly  ammoniacal  alcohol,  filtered,  the 
filtrate  evaporated  to  a  small  volume  and  allowed  to  ciystallize.  If  no  tyrosin  crys- 
tals are  obtained,  then  dilute  with  water,  precipitate  again  with  basic  lead  acetate,  and 
proceed  as  before.  If  tyrosin  crystals  now  separate,  they  are  filtered,  and  the  filtiate 
still  further  concentrated  to  obtain  the  leucin  crystals. 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  18,  S.  35 ;  Zeitschr.  f.  anal.  Chem.,  Bd.  24,  S 
153. 

'  Zeitschr.  f.  klin.  ]\Icd.,  Bd.  5. 

'  See  Rosin,  Vircbow's  Arch.,  Bd.  123. 


512  URINE. 

Cystin  (C,H,]SrSO,),.  This  body  is,  according  to  Baijmaitn,  to  be  con= 
sidered  as  disulphide,     '      >C<.  ^^  >LC         ' ,  or  the  previously 

mentioned  cystein,  C,H,NSO,  (page  483).      Cystein  itself  is  «r-amidothio- 
lactic  acid,    ^     "/C<r  ppj^jxT-      Cystin  is  converted  into  cystein  by  nascent 

hydrogen,  and  is  reconverted  into  cystin  by  oxidation. 

Baumank  and  Goldmank  claim  that  a  substance  similar  to  cystin 
occurs  in  very  small  amounts  in  normal  urine.  This  substance  occurs  in 
large  quantities  in  the  urine  of  dogs  after  poisoning  vrith  phosjDhorus. 
Cystin  itself  is  only  found  with  positiveness,  and  even  then  very  rarely,  in 
urinary  calculi  and  in  pathological  urines,  from  Avhich  it  may  separate  as  a 
sediment.  Cystinuria  occurs  oftener  in  men  than  in  women,  and  cystin 
seems  to  be  an  abnormal  splitting  product  of  the  proteids.  Baumann  and 
Y.  Udkanszkt  found  in  urine  in  cystinuria  the  two  diamins,  cadaverin 
(pentamethylendiamin)  and  putrescin  (tetramethylendiamin),  which  are 
produced  in  the  putrefaction  of  proteids.  These  two  diamins  were  also 
found  in  the  contents  of  the  intestine  in  cystinuria,  while  under  normal 
cohditions  they  are  not  present.  Hammarsten"  therefore  considers  that 
perhaps  some  connection  exists  between  the  formation  of  diamins  in  the 
intestine,  by  the  peculiar  jDutrefaction  in  cystinuria,  and  cystinuria  itself. 
Cadaverin  was  detected  in  the  urine  in  cystinuria  by  Stadthagb^s"  and 
Briegek.  Cystin  has  also  been  found  in  ox-kidneys,  in  the  liver  of  the 
horse  and  dolphin  (Drechsel),  and  as  traces  in  the  liver  of  a  drunkard. 
KiJLZ  '  once  observed  the  occurrence  of  cystin  during  the  digestion  of  fibrin 
with  pancreas. 

Cystin  crystallizes  in  thin,  colorless,  six-sided  plates.  It  is  not  soluble 
either  in  water,  alcohol,  ether,  or  acetic  acid,  but  dissolves  in  mineral  acids 
and  oxalic  acid.  It  also  dissolves  in  alkalies  and  in  ammonia,  but  not  in 
ammonium  carbonate.  Cystin  is  optically  active  and  strongly  laevo-rotatory. 
If  cystin  is  boiled  with  caustic  alkali  it  decomposes,  yielding  among  other 
products  alkali  sulphides,  which  may  be  detected  by  lead  acetate  or  sodium 
nitroprusside.  On  treating  cystin  with  tin  and  hydrochloric  acid,  only  a 
little  sulphuretted  hydrogen  is  evolved  and  cystein  is  produced.  On 
shaking  a  solution  of  cystin  in  an  excess  of  caustic  soda  with  benzoyl- 
chloride  a  voluminous  precipitate  of  benzoyl-cystin  is  produced  (BaumakN" 
and  Goldmann).  On  heating  on  platinum  foil  cystin  does  not  melt,  but 
ignites  and  burns  with  a  bluish-green  flame  accompanied  by  a  peculiar 

'  Bauii'.aiiu,  Zeitschr.  f.  physiol.  Clicm.,  Bd.  8.  In  regard  to  the  literature  on  cystin 
see  Brenziiigcr,  ibid.,  Bd.  IG,  S.  552;  Baumanii  aud  Goldnianu,  ibid.,  Bd.  12;  Bau- 
mann  and  w  Udranszky,  ibid.,  Bd.  13;  Stadthagcn  and  Brieger,  Berlin,  klin.  Wochen- 
scbr.,  1889;  Drechsel,  Du  Bois-Reymoud's  Arch.,  1891,  and  Zeitschr.  f.  Biologie,  Bd. 
33  ;  KUlz,  ibid.,  Bd.  27. 


CTsriN.  613 

sharp  odor.  On  warming  with  nitric  acid  cystin  dissolves  witli  decomposi- 
tion and  leaves  a  reddish-brown  residue  on  evaporation  which  does  not  give 
the  murexid  test. 

Cystein  liydrochloride  gives  a  nearly  insoluble  precipitate  having  the 
composition  2(C,n;-NS0,)  -f  3HgCl,  with  mercuric  chloride.  Baumann" 
and  IJoRissow  '  have  based  a  method  for  the  quantitative  estimation  of 
cystin  on  this  behavior.  They  first  reduce  the  cystin  by  zinc  and  liydro- 
chloric  acid. 

Cystin  is  easily  prepared  from  cystin  calculi  by  dissolving  them  in 
alkali  carbonate,  precipitating  the  solution  with  acetic  acid,  and  redissolving 
the  precipitate  in  ammonia.  'J'lie  cystin  crystallizes  on  the  spontaneous 
.evaporation  of  the  ammonia.  The  cystin  dissolved  in  the  urine  is  detected, 
in  the  absence  of  proteid  and  sulphuretted  hydrogen,  by  boiling  with  alkali 
and  testing  with  lead  salt  or  sodium  nitroprnsside.  To  isolate  cystin  from 
the  urine,  acidify  the  urine  strongly  with  acetic  acid.  The  precipitate  con- 
taining cystin  is  collected  after  24  hours  and  digested  with  hydrochloric 
acid,  which  dissolves  the  cystin  and  calcium  oxalate,  leaving  the  uric  acid 
undissolved.  Filter,  sujiersaturate  the  filtrate  with  ammonia  carbonate, 
and  treat  the  precipitate  with  ammonia,  which  dissolves  the  cystin  and 
leaves  the  calcium  oxalate.  Filter  again  and  precipitate  with  acetic  acid. 
The  precipitated  cystin  is  identified  by  the  microscope  and  the  above- 
mentioned  reactions.  Cystin  as  a  sediment  is  identified  by  the  microscope. 
It  must  be  purified  by  dissolving  in  ammonia  and  precipitating  with  acetic 
acid  and  then  tested.  Traces  of  dissolved  cystin  may  be  detected  by  the 
production  of  benzoyl-cystin,  according  to  Baumann  and  GoLDMAN^^ 

VII.     Urinary  Sediiiieiits  and  Calculi. 

Urinary  sediment  is  the  more  or  less  abundant  deposit  which  is  found  in 
the  urine  after  standing.  This  deposit  may  consist  partly  of  organized  and 
partly  of  non-organized  constituents.  The  first,  consisting  of  cells  of  various 
kinds,  yeast-fungi,  bacteria,  spermatozoa,  casts,  etc.,  must  be  investigated 
by  means  of  the  microscope,  i.iid  the  following  only  applies  to  the  non- 
organized deposits. 

As  above  mentioned  (page  406),  the  urine  of  healthy  individuals  may 
sometimes,  even  on  voiding,  be  cloudy  on  account  of  the  phosphates  present, 
or  become  so  after  a  little  while  because  of  the  separation  of  urates.  As  a 
rule,  urine  just  voided  is  clear,  and  after  cooling  shows  only  a  faint  cloud 
(nubecula)  which  consists  of  so-called  mucous,  a  few  epithelium-cells,  mucous 
corpuscles,  and  urate  particles.  If  an  acid  urine  is  allowed  to  stand,  it  will 
gradually  change;  it  becomes  darker  and  deposits  a  sediment  consisting  of 
uric  acid  or  urates,  and  sometimes  also  calcium-oxalate  crystals,  in  which 
yeast-fungi  and  bacteria  are  often  to  be  seen.  This  change,  which  the 
earlier  investigators  called  "  acid  fermentation"  of  the  urine,"  is  gener- 
ally considered  as  an  exchange  of  the  di-hydrogen  alkali  phosphates  with  the 

'  Zeitschr.  f.  physiol.  Chem. ,  Bd.  19. 


514  URINE. 

biurates  of  the  urine.  Mono-hydrogen  phosphates  besides  acid  urates 
(quadriurates)  or  free  uric  acid  or  a  mixture  of  both,  according  to  condi- 
tions/ are  hereby  formed.  The  quadriurates  may  also  split  into  biurate, 
which  passes  into  solution,  and  crystalline  uric  acid. 

Sooner  or  later,  sometimes  only  after  several  weeks,  the  reaction  of  the 
original  acid  urine  changes  and  becomes  neutral  or  alkaline.  The  urine  has 
now  passed  into  the  "alkaline  fermentation,"  which  consists  in  the 
decomposition  of  the  urea  into  carbon-dioxide  and  ammonia  by  means  of  lower- 
organisms,  micrococcus  urese,  bacteria  urese,  and  other  bacteria,  Musculus' 
has  isolated  an  enzyme  from  the  micrococcus  ureae  which  decomposes  urea 
and  is  soluble  in  water.  During  the  alkaline  fermentation  volatile  fatty 
acids,  especially  acetic  acid,  may  be  produced,  chiefly  by  the  fermentation  of 
the  carbohydrates  of  the  urine  (Salkowski').  A  fermentation  by  which 
nitric  acid  is  reduced  to  nitrous  acid,  and  another  where  sulphuretted 
hydrogen  is  produced,  may  sometimes  occur. 

When  the  alkaline  fermentation  has  advanced  only  so  far  as  to  render 
the  reaction  neutral,  we  often  find  in  the  sediment  fragments  of  iiric-acid 
crystals,  sometimes  covered  with  prismatic  crystals  of  alkali  urate;  dark- 
co^red  spheres  of  ammonium  urate,  crystals  of  calcium  oxalate,  and 
sometimes  crystallized  calcium  phosphate  are  also  found.  Crystals  of  am- 
monium-magnesium phosphate  (triple  phosphate)  and  spherical  ammonium 
urate  are  specially  characteristic  of  alkaline  fermentation.  The  urine  in 
alkaline  fermentation  becomes  paler  and  is  often  covered  with  a  fine  mem- 
brane which  contains  amorphous  calcium  phosphate  and  glistening  crystals 
of  triple  phosphate  and  numerous  micro-organisms. 

Non-organized  Sediments. 

Uric  Acid.  This  acid  occurs  in  acid  urines  as  colored  crystals  which  are 
identified  partly  by  their  form  and  partly  by  their  property  of  giving  the 
murexid  test.  On  warming  the  urine  they  are  not  dissolved.  On  the 
addition  of  caustic  alkali  to  the  sediment  the  crystals  dissolve,  and  when  a 
drop  of  this  solution  is  placed  on  a  microscope-slide  and  treated  with  a  drop 
of  hydrochloric  acid,  small  crystals  of  uric  acid  are  obtained  which  are  easily 
seen  under  the  microscope. 

Acid  Urates.  These  occur  only  in  the  sediment  of  acid  or  neutral 
urines.  They  are  amorphous,  clay-yellow,  brick-red,  rose-colored,  or  brown- 
ish red.  They  differ  from  other  sediments  in  that  they  dissolve  on  warming 
the  urine.  They  give  the  murexid  test,  and  small  microscopic  crystals  of 
uric  acid  separate  on  the  addition  of  hydrochloric  acid.     Crystalline  alkali 

*  See  Huppert-Neubauer,  10.  Aull.,  and  A.  Ritter,  Zeitschr.  f.  Biologic,  Bd.  35. 
^  Musculus,  PflUger's  Arch.,  Bd.  12. 

*  Salkowski,  Zeitschr.  f.  pliysiol.  Cliem.,  Bd.  13. 


NONORUANIZRD  SEDIMENTS.  515 

urates  occur  very  rarely  in  the  urine,  and  us  a  rule  only  in  such  as  have 
become  neutral  but  not  alkaline  by  the  alkaline  fermentation.  The  crystals 
are  somewhat  similar  to  those  of  neutral  calcium  phosphate;  they  are  not 
dissolved  by  acetic"acid,  however,  but  give  a  cloudiness  therewith  due  to 
small  crystals  of  uric  acid. 

^immonium  urate  may  indeed  occur  as  a  sediment  in  a  neutral  urine 
which  at  first  was  strongly  acid  and  has  become  neutralized  by  the  alkaline 
fermentation,  but  it  is  only  characteristic  of  ammoniacal  urines.  This  sedi- 
ment consists  of  yellow  or  brownish,  rounded  spheres  which  are  often  covered 
with  thorny-shaped  prisms  and,  because  of  this,  are  rather  large  and  resemble 
the  thorn-apple.  It  gives  the  murexid  test.  It  is  dissolved  by  alkalies  wit'i 
the  development  of  ammonia,  and  crystals  of  uric  acid  separate  on  the  addi- 
tion of  hydrochloric  acid  to  this  solution. 

Calcinm  oxalate  occurs  in  the  sediment  generally  as  small,  shining, 
strongly  refractive  quadratic  octahedra,  which  on  microscopical  examination 
remind  one  of  a  letter-envelope.  The  crystals  can  only  be  mistaken  for 
small,  not  fully  developed  crystals  of  ammonium-magnesium  phosphate. 
They  differ  from  these  by  their  insolubility  in  acetic  acid.  The  oxalate  may 
also  occur  as  flat,  oval,  or  nearly  circular  disks  with  central  cavities  which 
from  the  side  appear  like  an  hour-glass.  Calcinm  oxalate  may  occur  as  a 
sediment  in  an  acid  as  well  as  in  a  neutral  or  alkaline  urine.  The  quantity 
of  calcium  oxalate  separated  from  the  urine  as  sediment  depends  not  only 
upon  the  amount  of  this  salt  present,  but  also  upon  the  acidity  of  urine. 
The  solvent  for  the  oxalate  in  the  urine  seems  to  be  the  di-acid  alkali  phos- 
phate, and  the  greater  the  quantity  of  this  salt  in  the  urine  the  greater  the 
quantity  of  oxalate  in  solution.  When,  as  above  mentioned  (page  513),  the 
simple-acid  phosphate  is  formed  from  the  di-acid  phosphate,  on  allowing 
the  urine  to  stand,  a  corresponding  part  of  the  oxalate  may  be  separated  as 
sediment. 

Calcinm  carbonate  occurs  in  considerable  quantities  as  sediment  in  the 
urine  of  herbivora.  It  occurs  in  but  small  quantities  as  a  sediment  in  human 
urine,  and  in  fact  only  in  alkaline  urines.  It  either  has  almost  the  same 
appearance  as  amorphous  calcium  oxalate,  or  it  occurs  as  somewhat  larger 
spheres  with  concentric  bands.  It  dissolves  in  acetic  acid  with  the  genera- 
tion of  gas,  which  differentiates  it  from  calcium  oxalate.  It  is  not  yellow 
or  brown  like  ammonium  urate,  and  does  not  give  the  murexid  test. 

Calcium  sulphate  occurs  very  rarely  as  a  sediment  in  strongly  ncid  urine.     It  appears 
as  long,  thin,  colorless  needles,  or  generally  sis  plates  grouped  together. 

Calcinm  FJiosphate.  The  calcium  triphosphate,  Ca,(PO,), ,  which 
occurs  only  in  alkaline  urines,  is  always  amorphous  and  occurs  partly  as  a 
colorless,  very  fine  powder  and  partly  as  a  membrane  consisting  of  very  fine 
granules.  It  differs  from  the  amorphous  urates  in  that  it  is  colorless,  dis- 
solves  in  acetic   acid,   but   remains   undissolved   on   warming   the   urine. 


§16  UBINE. 

Calcium  diphosphate,  CaHPO^  4-2HjO,  occurs  in  neutral  or  only  in  very 
faintly  acid  urine.  It  is  found  sometimes  as  a  thin  film  covering  the  urine, 
and  sometimes  as  a  sediment.  In  crystallizing,  the  crystals  may  be  single, 
or  they  may  cross  one  another,  or  they  may  be  arranged  in  groups  of  color- 
less, Avedge-shaped  crystals  whose  wide  end  is  sharply  defined.  These  crys- 
tals difl:er  from  crystalline  alkali  urates  in  that  they  dissolve  without  a 
residue  in  dilute  acids  and  do  not  give  the  murexid  test. 

Amynonium-magnesium  iiilwsphate,  triple  phosphate,  may  sej^arate  of 
course  from  an  amj)hoteric  urine  in  the  presence  of  a  sufficient  quantity  of 
ammonium  salts,  but  it  is  generally  characteristic  of  a  urine  become 
ammoniacal  through  alkaline  fermentation.  The  crystals  are  so  large  that 
they  may  be  seen  with  the  unaided  eye  as  colorless  glistening  particles  in 
the  sediment,  on  the  walls  of  the  vessel,  and  in  the  film  on  the  surface  of 
the  urine.  This  salt  forms  large  prismatic  crystals  of  the  rhombic  system 
(coflfin-shaped)  which  are  easily  soluble  in  acetic  acid.  Amorphous  magne- 
sium tri2)hosphate,  Mg,(P0j3,  occurs  with  calcium  triphosphate  in  urines 
rendered  alkaline  by  a  fixed  alkali.  Crystalline  magnesium  phosphate, 
AIg3(P0 J,  +  2211,0,  has  been  observed  in  a  few  cases  in  human  urine 
^also  in  horse's  urine)  as  strongly  refractive,  long  rhombic  plates. 

Kyestein  is  the  film  which  appears  after  a  little  while  on  the  surface  of  the  urine.  This 
coating,  which  was  formerly  considered  as  characteristic  of  urine  in  j^reguancy,  contains 
various  elements,  such  as  fungi,  vibriones,  epithelium-cells,  etc.  It  often  contains 
■earthy  phosphates  and  triple-phosphate  crystals. 

As  more  rare  sediments  we  find  cystin,  iprosin,  hippuric  acid,  xaniJdn,  hmmaioidin. 
In  alkaline  urine  blue  crystals  of  indigo  may  also  occur,  due  to  a  decomposition  of 
indoxyl-glycuronic  acid. 

Urinary  Calculi. 

Besides  certain  pathological  constituents  of  the  urine,  all  those  uriuary 
constituents  which  occur  as  sediments  take  part  in  the  formation  of  the 
urinary  calculi.  Ebstein  *  considers  the  essential  difference  between  an 
amorphous  or  crystalline  sediment  in  the  urine  on  one  side  and  urinary 
sand  or  large  calculi  on  the  other  to  be  the  occurrence  of  an  organic  frame 
in  the  last.  As  the  sediments  Avhich  ajipear  in  normal  acid  urine  and  in  a 
urine  alkaline  through  fermentation  are  different,  so  also  are  the  urinary 
calculi  which  appear  under  corresponding  conditions. 

If  the  formation  of  a  calculus  and  its  furtlier  development  take  place  in 
an  undecomposed  urine,  it  la  called  a  primary  formation.  If,  on  the  con- 
trary, the  urine  has  undergone  alkaline  fermentation  and  the  ammonia 
formed  thereby  has  given  rise  to  a  calculous  formation  by  precipitating 
ammonium  urate,  triple  phosphate,  and  earthy  phosphates,  then  it  is  called 
a  secondary  formation.     Such  a  formation  takes  place,  for  instance,  when 


'  Die  Natur  und  Behandlung  der  Ilarnstine.     Wiesbaden,  1884. 


URINARY  CALCULI.  517 

a  foreign  body  in  tlie  bladder  produces  catarrh  accompanied  by  alkaline 
fermentation. 

We  discriminate  between  the  nucleus  or  nuclei — if  such  can  be  seen — 
and  the  different  layers  of  the  calculus.  The  nucleus  may  be  essentially 
different  in  dilferent  cases,  for  quite  frequently  it  consists  of  a  foreign  body 
introduced  into  the  bladder.  The  calculus  may  have  more  than  one  nu- 
cleus. In  a  tabulation  made  by  Ultzmaxn  of  545  cases  of  urinary  calculi, 
the  nucleus  in  80,9^  of  the  cases  consisted  of  uric  acid  (and  urates);  iu 
b.di'fc,  of  calcium  oxalate;  in  8.6^,  of  earthy  phosphates;  in  1.4^,  of  cystin; 
and  in  3.3^,  of  some  foreign  body. 

During  the  growth  of  a  calculus  it  often  happens  that,  for  some  reason 
or  other,  the  original  calculus-forming  substance  is  covered  with  another 
layer  of  a  different  substance.  A  new  layer  of  the  original  substance  may 
deposit  on  the  outside  of  this,  and  this  process  may  be  repeated.  In  this 
way  a  calculus  consisting  originally  of  a  simple  stone  may  be  converted  into 
a  so-called  compound  stone  with  several  layers  of  different  substances. 
Such  calculi  are  always  formed  when  a  jjrimary  is  changed  into  a  secondary 
formation.  By  the  continued  action  of  an  alkaline  urine  containing  pus, 
the  primary  constituents  of  an  originally  primary  calculus  may  be  partly 
dissolved  and  be  replaced  by  phosphates.  Metamorphosed  urinary  calculi 
are  formed  in  this  way. 

Uric-acid  calculi  are  very  abundant.  They  are  variable  in  size  and 
form.  The  size  of  the  bladder-stone  varies  from  that  of  a  pea  or  bean  to 
that  of  a  goose-egg.  Uric-acid  stones  are  always  colored;  generally  they 
are  grayish  yellow,  yellowish  brown,  or  pale  red-brown.  The  upper  surface 
is  sometimes  entirely  even  or  smooth,  sometimes  rough  or  uneven.  Next 
to  the  oxalate  calculus,  the  uric-acid  calculus  is  the  hardest.  The  fractured 
surface  shows  regular  concentric,  unequally  colored  layers  which  may  often 
be  removed  as  shells.  These  calculi  are  formed  primarily.  Layers  of  uric 
acid  sometimes  alternate  with  other  layers  of  primary  formation,  most 
frequently  with  layers  of  calcium  oxalate.  The  simple  uric-acid  calculus 
leaves  very  little  residue  when  burnt  on  platinum-foil.  It  gives  the 
murexid  test,  but  there  is  no  material  development  of  ammonia  when  acted 
on  by  caixstic  sodn. 

Ammonium-nrate  calculi  occur  as  primary  calculi  in  new-born  or  nurs- 
ing infants,  rarely  in  grown  persons.  They  often  occur  as  a  secondary 
formation.  The  primary  stones  are  small,  with  a  pale-yellow  or  dark- 
yellowish  surface.  When  moist  they  are  almost  like  dough ;  in  the  dry  state 
they  are  earthy,  easily  crumbling  into  a  pale  powder.  They  give  the 
murexid  test,  and  develop  much  ammonia  with  caustic  soda. 

Calcinm-oxalate  calculi  are,  next  to  uric-acid  calculi,  the  most  abundant. 
They  are  either  smooth  and  small  (hemp-seed  calculi)  or  larger,  of  tho 
size  of  a  hen's  egg,  with  rough,  uneven  surface,  or  their  surface  is  covered 


618  URINE. 

with  prongs  (mulberry  calculi).  These  calculi  produce  blecdiug  easily, 
and  therefore  they  often  have  a  dark -brown  surface  due  to  decomposed  blood- 
coloring  matters.  Among  the  calculi  occurring  in  man  these  are  the  hardest. 
They  dissolve  in  hydrochloric  acid  without  developing  gas,  but  are  not 
soluble  in  acetic  acid.  After  gently  heating  the  powder,  it  dissolves  in  acetic 
acid  Avith  frothing.  With  more  intense  heat  it  becomes  alkaline,  due  to  the 
production  of  quicklime. 

Pliospliate  Calculi.  These,  which  consist  mainly  of  a  mixture  of  the 
normal  phosphate  of  the  alkaline  earths  with  triple  phosphate,  may  be  very 
large.  They  are  as  a  rule  of  secondary  formation,  and  contain  besides  these 
phosphates  also  some  ammonium  urate  and  calcium  oxalate.  These  calculi 
oi'diuarily  consist  of  a  mixture  of  these  three  constituents,  earthy  phosphate, 
triple  phosphate,  and  ammonium  urate,  surrounding  a  foreign  body  as  a 
nucleus.  Their  color  is  variable — white,  dingy  white,  pale  yellow,  some- 
times violet  or  lilac-colored  (from  indigo-red).  The  surface  is  always  rough. 
Calculi  consisting  of  triple  phosphate  alone  are  seldom  found.  They  are 
ordinarily  small,  with  granular  or  radiated  crystalline  fracture.  Stones  of 
ni'ono-acid  calcium  phosphate  are  also  seldom  obtained.  They  are  white  and 
nave  beautiful  crystalline  texture.  The  phosphatic  calculi  do  not  burn  up, 
and  the  powder  dissolves  in  acid  without  effervescence,  and  the  solution  gives 
the  reactions  for  phosphoric  acid  and  alkaline  earths.  The  triple-phosphate 
calculi  generate  ammonia  on  the  addition  of  an  alkali. 

Calcium-carbonnte  calculi  occur  cliicfly  in  beibivora.  They  are  seldom  found  in  man. 
They  have  mostly  chalky  properties,  and  are  ordinarily  white.  They  are  completely  or 
in  great  part  dissolved  by  acids  with  effervescence. 

Gystin  calculi  occur  but  seldom.  They  are  of  primary  formation,  of  various  sizes, 
sometimes  as  large  as  a  hen's  egg.  They  have  a  smooth  or  rougii  surface,  are  while  or 
pale  yellow,  and  have  a  crystalline  fracture.  They  are  not  very  hard  ;  they  are  con- 
sumed almost  entirely  on  platinum  foil,  burning  with  a  bluish  flame.  Thej'^  give  the 
above-mentioned  reactions  for  cystin. 

Xantldn  calculi  are  very  rarely  found.  They  are  also  of  primary  formation.  They 
vary  from  the  size  of  a  pea  to  that  of  a  hen's  egg.  They  are  whitish,  yellowish  brown 
or  cinnamon-brown  in  color,  of  medium  hardness,  with  amorphous  fracture,  and  on 
rubbing  appear  like  wax.  They  burn  up  completely  when  heated  on  platinum  foil. 
They  give  tlie  xanthiu  reaction  with  nitric  acid  and  alkali,  but  this  must  not  be  mistaken 
for  tiie  murexid  test. 

UroHtealith  calculi  have  been  observed  only  a  few  times.  In  the  moist  state  they  are 
soft  and  elastic  at  the  temperature  of  the  body,  but  in  the  dry  state  they  are  brittle,  with 
an  amorphous  fracture  and  waxy  appearance.  They  I)urn  with  a  luminous  flame 
when  heated  on  platinum  foil,  and  generate  an  odor  similar  to  resin  or  shellac.  Such  a 
calciilus,  investigated  by  Kuukknberg,'  consisted  of  parafline  derived  from  a  paraffine 
bougie  used  as  a  sound  on  the  patient.  Perhaps  the  urostealith  calculi  observed  in  other 
cases  had  a  similar  origin,  although  the  substances  of  which  they  consisted  have  not  been 
closely  studied.  Horbaczewski  has  recently  analyzed  a  case  of  urostealith  which,  to 
all  appearances,  was  formed  in  the  bladder.  This  calculus  contained  25  p.  m.  water, 
8  p.  m.  inorganic  bodies,  117  p.  m.  bodies  insoluble  in  ether,  and  850  p.  m.  organic 
bodies  soluble  in  ether,  among  which  were  515  p.  m.  free  fatty  acids,  335  p.  m.  fat,  and 
traces  of  cholesterin.  The  fatty  acids  consisted  of  a  mixture  of  stearic,  palmitic,  and 
probably  myristic  acids. 

'  Chem.  Untersuch.  z.  wlssensch.  Med.,  Bd.  2.  Cited  from  Maly's  Jahresber.,  Bd. 
19,  S.  422. 


URINARY  CALCULI  519 

HonBACZEWSKi '  lius  also  analyzed  a  bladder-sloue  wliich  contained  958.7  p.  in,  cho- 
letterin . 

Fibrin  ralnilt  sometimes  occur.  Tbev  consist  of  more  or  less  changed  fibrin  coagu- 
lum.     On  burning  llu-y  develop  an  odor  of  l)uriit  horn. 

The  chemicarinvestiyation  of  urinary  calculi  is  of  great  practical  impor- 
tauce.  To  make  such  an  examination  actually  instructive  it  is  necessary  to 
investigate  separately  the  ditferent  layers  which  constitute  the  calculus. 
For  this  purpose  saw  the  calculus,  previously  wrapped  in  paper,  with  a  fine 
saw  so  that  the  nucleus  becomes  accessible.  Then  peel  otf  the  dillerent 
layers,  or,  if  the  stone  is  to  be  kept,  scrape  off  enough  of  the  powder 
from  each  layer  for  examination.  This  powder  is  then  tested  by  heating  on 
platinum  foil.  It  must  not  be  forgotten  that  a  calculus  is  never  entirely 
burnt  up,  and  also  that  it  is  never  so  free  from  organic  matter  that 
on  heating  it  does  not  carbonize.  Do  not,  therefore,  lay  too  great  stress  on 
a  very  insignificant  uuburnt  residue  or  on  a  very  small  amount  of  organic 
matter,  but  consider  the  calculus  in  the  former  case  as  completely  burnt  and 
in  the  latter  as  not  burnt. 

When  the  powder  is  in  great  part  burnt  up,  but  a  significant  quantity  of 
unburut  residue  remains,  then  the  powder  in  question  contains  as  a  rule 
urates  mixed  with  inorganic  bodies.  In  such  cases  remove  the  urate  with 
boiling  water,  and  then  test  the  filtrate  for  uric  acid  and  the  suspected  bases. 
The  residue  is  then  tested  according  to  the  following  schema  of  Heller, 
which  is  well  adapted  to  the  investigation  of  urinary  calculi.  In  regard  to 
the  more  detailed  examination  the  reader  is  referred  to  special  works  on  the 
subject. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 


620 


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CHAPTER  XVI. 
THE   SKIN  AND  ITS   SECRETIONS. 

I'iH  the  structure  of  the  skin  of  man  and  vertebrates  many  different 
Icinds  of  snbstances  occnr  which  liave  already  been  treated  of,  snch  as  the 
constituents  of  the  epidermis  formation,  the  connective  and  fatty  tissues, 
the  nerves,  muscles,  etc.  Among  these  the  different  horn-formations,  the 
hair,  nails,  etc.,  whose  chief  constituent,  keratin,  has  been  spoken  of  in 
another  chapter  (Chap.  II),  are  of  special  interest. 

The  cells  of  the  horny  formation  show,  in  proportion  to  their  age,  a 
different  resistance  to  chemical  reagents,  especially  fixed  alkalies.  The 
younger  the  horn-cell  the  less  resistance  it  has  to  the  action  of  alkalies;  with 
advancing  age  the  resistance  becomes  greater,  and  the  cell-membranes  of 
many  horn-formations  are  nearly  insoluble  in  caustic  alkalies.  Keratin 
occurs  in  the  horn-formation  mixed  with  other  bodies,  from  which  it  ia 
isolated  with  difficulty.  Among  these  bodies  the  mineral  constituents  in 
many  cases  occupy  a  prominent  place  because  of  their  quantity.  Hair 
leaves  on  burning  5-70  p.  m.  ash,  which  may  contain  in  1000  parts  230 
parts  alkali  sulphates,  140  parts  calcium  sulphate,  100  parts  iron  oxide, 
and  even  400  parts  silicic  acid.  Dark  hair  on  burning  seems  generally, 
although  not  always,  to  yield  more  iron  oxide  than  blond.  The  nails 
fire  rich  in  calcium  phosphate,  and  the  feathers  rich  in  silicic  acid,  which 
Drechsel'  claims  exists  in  part  in  organic  combination  as  an  ester. 

The  granules  occurring  in  the  stratum  granulosum  of  the  skin  consist  of 
a  substance  which  has  been  called  eJeidin,  and  which  is  considered  as  an 
intermediate  step  in  the  transformation  of  the  protoplasm  into  keratin. 
Tiie  chemical  nature  of  this  substance  is  unknown. 

The  skin  of  invertebrates  has  been  the  subject,  in  a  few  cases,  of 
chemical  investigation,  and  in  these  animals  various  snbstances  have  been 
found,  of  which  a  few,  though  little  studied,  are  worth  discussing.  Among 
these  bodies  tunicin,  which  is  found  especially  in  the  tunic  of  the  tunicata, 
and  the  widely  diffused  cJiifin,  found  in  the  cuticle-formation  of  inverte- 
brates, are  of  interest. 

Tnnicin.  Cellulose  seems,  according  to  the  investigations  of  Ambronn,  to  occur 
rather  extensively  in  the  animal  kingdom  in  the  arthropoda  and  the  mollusks.  It  has 
been  known  for  a  long  time  as  the  tunic  of  the  tunicata,  and  this  animal  cellulose  was 

»  Centralbl.  f.  Physiol.  Bd.  11,  S.  361. 

521 


522  THE  SEIN  AND  ITS  SECRETIONS. 

called  luuicin  by  Bekthelot.  According  to  the  recent  investigations  of  Wintekstein 
there  does  not  seem  to  exist  anj'-  niarlied  difference  between  tunicin  and  ordinary  vege- 
table cellulose.  On  boiling  with  dilute  acid  tunicin  yields  dextrose,  as  shown  iirst  by 
FKAXcniMONT '  and  later  confirmed  by  Winterbtein. 

Chitin  is  uob  found  in  vertebrates.  In  invertebrates  cliitin  is  alleged  to 
occur  in  several  classes  of  animals;  but  it  can  only  be  positively  asserted 
that  true,  typical  chitin  is  found  only  in  articulated  animals,  in  vrhich  it 
forms  the  chief  organic  constituent  of  the  shell,  etc.  According  to 
Krawkow''  chitin  of  the  shell,  etc.,  does  not  seem  to  occur  free,  but  in 
combination  with  another  substance,  probably  a  proteid-like  body.  Chitin 
also  occurs,  according  to  Gilson  and  Winterstein,'  in  certain  fungi. 

According  to  Sundvik  the  formula  of  chitin  is  probably  C^^Hj^^NgOjg 
-f- ^(H^O),  where  n  may  vary  between  1  and -4,  and  it  is  probably  an 
amine  derivative  of  a  carbohydrate,  with  the  general  formula  n{G^Jl^fi^^). 
According  to  Kra.wkow  chitin  shows  different  origins  by  its  unequal 
behavior  with  iodine,  and  he  therefore  concludes  that  there  must  exist 
quite  a  group  of  chitins,  which  seem  to  be  amine  derivatives  of  different 
carbohydrates,  such  as  dextrose,  glycogen,  dextrins,  etc.  According  to 
Zander^  only  two  chitins  exist,  one  of  which  turns  violet  with  iodine  and 
ziEtc  chloride,  and  the  other  brown. 

Chitin  is  decomposed  on  boiling  with  mineral  acids  and  yields,  as  shown 
by  Ledderhose,  glucosamin  and  acetic  acid.  Schmiedeberg  ^  therefore 
considers  chitin  as  a  probable  acetyl  acetic-acid  combination  of  glucosamin. 
If,  as  previously  mentioned  (page  318),  the  chondroitin-sulphuric  acid 
contains  a  glucosamin  group,  as  made  probable  by  the  investigations  of 
Schmiedeberg,  then,  according  to  Schmiedeberg,  glucosamin  forms  the 
bridge  which  leads  from  the  chitin  of  lower  animals  to  the  cartilage  of 
higher  organized  beings. 

In  the  dry  state  chitin  forms  a  white,  brittle  mass  retaining  the  form  of 
the  original  tissue.  It  is  insoluble  in  boiling  water,  alcohol,  ether,  acetic 
acid,  dilute  mineral  acids,  and  dilute  alkalies.  It  is  soluble  in  concentrated 
acids.  It  is  dissolved  without  decomposing  in  cold  concentrated  hydro- 
chloric acid,  but  is  decomposed  by  boiling  hydrochloric  acid.  When  chitin 
is  dissolved  in  concentrated  sulphuric  acid  and  the  solution  dropped  into 
boiling  water  and  then  boiled,  we  obtain  a  substance  (glucosamin,  chitos- 
amin)  which  reduces  copper  suboxide  in  alkaline  solutions.     On  heating 

'  Ambroun,  Maly's  Jahresber.,  Bd.  20;  Bertlielot,  Annal.  de  Chim.  et  Phys.,  Tome 
56,  Compt.  rend.,  Tome  47 ;  Wintersteiu,  Zeitschr.  f.  physiol.  Chem.,  Bd.  18;  Franchi- 
mont,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  12. 

^  Zeitschr.  f.  Biologic,  Bd.  29. 

'  Gilson,  Compt.  rend.,  Tome  120;  Wiuterstein,  Ber.  d.  deutsch.  chem.  Gesellsch,, 
Bdd.  27  and  28. 

*  Sundvik,  Zeitschr.  f.  physiol.  Chem.,  Bd.  5  ;  Zander,  Pfliiger's  Arch.,  Bd.  66. 

'Ledderhose,  Zeitschr.  f.  physiol.  Chem.,  Bdd.  2  and  4 ;  Schmiedeberg,  Arch.  f. 
«xp.  Path.  u.  Pharm.,  Bd.  28. 


CIIITIN  A^D   II y A  LIN.  D-*3 

chitin  with  alkali  and  a  little  water  to  180°  C.  a  cleavage  takes  place, 
accordiug  to  IIoppe-Seyler  and  Araki,'  with  tlio  formation  of  a  new 
fiubsfauce,  chifosau,  C,,LI„N,0,, ,  which  retains  the  siiape  of  the  original 
chitin  and  the  t4)litting  off  of  acetic  acid.  Ciiitosan  is  dissolved  by  dihite 
acids,  also  acetic  acid,  and  is  colored  violet  by  a  dilute  iodine  solution.  It 
splits  into  acetic  acid  and  glucosamin  by  the  action  of  hydrochloric  acid. 
On  heating  with  acetic  anhydride  it  is  converted  into  a  chitin-like  sub- 
stance, which  is  not  identical  with  chitin  and  contains  at  least  three  acetyl 
groups.  According  to  Krawkow  the  various  chitins  behave  differently 
with  iodine  or  with  sulphuric  acid  and  iodine,  in  that  some  are  colored 
reddish  brown,  blue,  or  violet,  while  others  are  not  colored  at  all. 

Chitin  may  be  easily  prepared  from  the  Avings  of  insects  or  from  the 
shells  of  the  lobster  or  the  crab,  the  last  mentioned  having  first  been 
extracted  by  an  acid  so  as  to  remove  the  lime  salts.  The  wings  or  shells 
are  boiled  with  caustic  alkali  until  they  are  white,  afterward  washed  with 
water,  then  with  dilute  acid  and  water,  and  lastly  extracted  with  alcohol 
and  ether.  If  chitin  so  prepared  is  dissolved  in  cold,  concentrated  sulphuric 
acid  anil  diluted  with  cold  water,  then  pure  chitin  separates  out,  having 
been  set  free  from  the  combination  with  the  other  body  (Krawkow). 

Chitosnmin,  glucosamin,  1ms  recently  been  prepared  in  the  crystalline  state  by  de 
BuuYN  !ind  VAN  Ekenstein  and  also  by  Breuer."  It  is  remarkably  easily  soluble  in 
water,  but  with  difficulty  in  cold  and  hot  ethyl  alcohol  and  in  cold  metiiyl  alcohol.  It 
is  insoluble  in  etlicr  and  cidoroforin.  It  is  dextro-rotatorj-,  has  a  strong  reducing  .-iction, 
and  de"omposLS  very  readily.  Chitosamin  gives  a  plicnylglucosnzon  with  jilienj-lliydra- 
ziu  and  acetic  acid.  In  methyl-alcuhol  solution  a  crystalline  substance  gradually  settles 
which  is  identical  with  the  substance  which  slowly  deposits  from  a  solution  of  Icvulose 
in  auimoniacal  methyl  alcohol.  The  formation  of  this  substance,  which  de  Bruyn  and 
Ekenstein  have  called  fructosamin,  and  which  gives  no  combination  witii  hydrocliloric 
acid,  shows,  according  to  these  investigators,  that  the  sugar  from  which  chitosamin  is 
derived  stands  in  connection  with  ordinary  levulose  (see  page  75). 

Chitosamin  hydrochloride  is  readily  obtained  by  boiling  chitin  (lobster-shell)  with 
concentrated  hydrochloric  acid. 

Hyalin  is  the  chief  organic  constituent  of  the  walls  of  hydatid  cysts.  From  a  chem- 
ical point  of  view  it  stands  close  to  chitin,  or  between  it  and  the  proteid.  In  old  and 
more  transparent  sacs  it  is  tolerably  free  from  mineral  bodies,  but  in  younger  sacs  it  con- 
*ains  a  great  quantity  (16;?)  of  lime  salts  (carbonate,  phosphate,  and  sulphate). 

According  to  Lucke  '  its  composition  is  : 

C  H  N  O 

From  old  cysts 45.3        G.5        5.2        43.0 

From  yoiuig  cysts 44.1         6.7        4.5        44.7 

It  differs  from  keratin  on  the  one  hand  and  from  proteids  on  the  other  by  the  absence 
of  sul)iliur,  also  b}'  its  yielding,  when  boiled  with  dihUe  sulphiiric  acid,  a  variety  of 
sugar  in  large  quantities  (50;?),  which  is  reducing,  fermentable,  and  dextrogyrate.  It 
dilTirs  from  chitin  by  the  property  of  being  gradually  dissolved  by  caustic  potash  or  soda, 
or  by  dilute  acids  ;  also  by  its  .solubility  on  heating  with  water  to  150°  C. 

Tlie  coloring  matters  of  the  skin  and  horn-formations  are  of  different 
kinds,  but  have  not  been  much  studied.      Those  occurring  in  the  stratum 

'  Zeitschr.  f.  physiol.  Chera.,  Bd.  20. 

'  De  Bruyn  and  Ekenstein,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  31,  S.  2476  ; 
Breuer,  iUd.,  S.  2193. 

'  Virchow's  Arch.,  Bd.  19. 


524  THE  SKIN  AND  ITS  SECRETIONS 

Malpighii  of  the  skin,  especially  of  the  negro,  and  the  black  or  brown 
pigment  occurring  in  the  hair,  belong  to  the  gronp  of  pigments  which 
have  received  the  name  inelanins. 

Melanins.  This  group  includes  several  different  varieties  of  amorphous 
black  or  brown  pigments  which  are  insoluble  in  Avater,  alcohol,  ether, 
chloroform,  and  dilute  acids,  and  which  occur  in  the  skin,  hair,  epithelium- 
cells  of  the  retina,  in  sepia,  in  certain  pathological  formations,  and  in  the. 
blood  and  urine  in  disease  Of  these  pigments  there  are  a  few,  such  as  the- 
melanin  of  the  eye,  Schmiedeberg's  sarcofnekmin,  and  that  from  the: 
melanotic  sarcomata  of  horses,  the  liipjjomelanin  (JSTencki  and  Beedez '), 
which  are  soluble  with  difficulty  in  alkalies,  while  others,  such  as  the 
pigment  of  the  hair  and  the  coloring  matter  of  certain  pathological  swellings 
in  man,  the  phymatorusin  (Nencki  and  Berdez),  are  easily  soluble  in. 
alkalies.  The  humus-like  products,  called  melanoidic  acids  by  Schmiede- 
BERG,  obtained  on  boiling  proteids  with  mineral  acids,  are  rather  easily 
soluble  in  alkalies.  Chittenden-  and  Albro  ""  have  prepared  melanin-like 
pigments  by  boiling  antialbumid  and  hemipeptone  with  dilute  sulphuric 
acid..  They  were  insoluble  in  water,  alcohol,  and  ether,  but  were  soluble,  on 
the^ontrary,  in  dilute  alkalies.  The  composition  was  somewhat  different 
according  to  the  length  of  boiling.  The  melanin  from  antialbumid  was. 
poorer  in  carbon  (54-58^)  and  richer  in  sulphur  (4.35-7.7^)  than  th& 
melanin  from  hemipeptone,  which  contained  61.5^  carbon  and  2.98^ 
sulphur. 

Among  the  melanins  there  are  a  few,  for  examples  the  choroid  pigment,, 
which  are  free  from  sulphur;  others,  on  the  contrary,  as  sarcomelanin  and 
the  pigment  of  the  hair  and  of  horse-hair,  are  rather  rich  in  sulphur  (2-4,'^), 
while  the  phymatorusin  found  in  certain  swellings  and  in  the  urine  (Nencki 
and  Berdez,  K.  Morner)  is  very  rich  in  sulphur  (8-10^).  Whether  any 
of  these  pigments,  especially  the  phymatorusin,  contains  any  iron  or  not  is 
an  important  though  disputed  point,  for  it  leads  to  the  question  whether 
these  pigments  are  formed  from  the  blood-coloring  matters.  The  pigment 
phymatorusin,  isolated  by  Nencki  and  Berdez  from  melanotic  sarcomata, 
is,  according  to  them,  free  from  iron  and  is  not  a  derivative  of  hajmoglobin. 
K.  Morner  and  later  also  Brandl  and  L.  Pfeiffer  found,  on  the  con- 
trary, that  this  pigment  did  contain  iron,  and  they  consider  it  as  a  deriva- 
tive of  the  blood-pigments.  The  sarcomelanin  (from  a  sarcomatous  liver) 
analyzed  by  Schmiedeberg  contained  2.7^  iron,  which  was  in  organic 
comloination  in  part  and  could  not  be  completely  removed  by  dilate 
hydrochloric  acid.  The  sarcomelcminic  acid  prepared  by  ScnMiEDEBERG 
by  the  action  of  alkali  on  this  melanin  contained  1.07^  iron.     Tiie  diffi- 

'  Arch,  f .  exp.  Path.  u.  Phurm.,  Bdd.  20  and  24. 
'  Amer.  Jouin.  of  Physiol.,  Vol.  2. 


M ELAN  INS  AND   0  Til  EH  PIGMENTS.  525 

cnlties  wliicli  attend  the  isolation  and  ])urirication  of  the  melanins  liave  not 
been  overcome  in  certain  cases,  while  in  others  it  is  questionable  whether 
the  final  product  obtaiued  has  not  another  composition  than  the  original 
coloring  matter,  owing  to  the  energetic  chemical  processes  resorted  to  in  its 
purification.  Under  such  circumstances  it  seems  that  a  tabulation  of  the 
analyses  of  dilTerent  melanin  preparations  made  up  to  the  present  time  are 
of  secondary  importance. ' 

The  one  or  more  pigments  of  the  human  hair  have  a  low  percentage 
of  nitrogen,  8.5^  (Sieber),  and  a  variable  but  considerable  amount  of 
sulphur,  2.71-4.10^.  The  great  quantity  of  iron  oxide  which  remains  on 
incinerating  hair  does  not  seem  to  belong  to  the  pigments.  The  pigment 
of  the  negro's  skin  and  hair  was  found  entirely  free  from  iron  by  Abel  and 
Davis." 

In  addition  to  the  coloring  inaUeis  of  tlif  liumiin  skin  it  is  in  place  here  to  treat  of 
the  pigments  foiiml  in  tlic  skin  or  ci>i(Iennis-foiniation  of  animals. 

The  bcanliful  color  of  the  fealhcis  of  many  birds  dejieiids  in  certain  cases  on  purely 
physical  causes  ('nlcrferenct'-plienoniena),  but  in  oilier  cases  on  coloring  matters  of  vari- 
ous kinds.  Such  a  coloring  mattir  is  the  aniorphotis  reddish-violet  turncin,  which  con- 
tains 1%  copper  and  whose  spectrum  is  very  similar  t<>  tliai  of  o.\yha?moglobin.  Kku- 
KENBEUo'  found  a  large  number  of  coloring  nuitters  in  birds'  feathers,  namely,  zooery- 
thrin.  zoofulnn,  tnracoverdin,  zoovtihin,  jmt(acoJuivi7i,  and  others  which  cannot  be 
cuumcralcd  here. 

Tetronerythrin,  so  named  by  WuKM,  is  a  red  amorphous  pigment,  which  is  soluble  in 
alcohol  and  ether,  and  which  occurs  in  the  red  warty  spots  over  the  eyes  of  the  heath- 
cock  and  tlie  grouse,  and  which  is  very  widely  spread  among  the  invertebrates  (Halli- 
BUUTox,  De  Mkukjkowski,  ]\I.\c^Iunn^.  Besides  tetronerythrin  3IacMtjnn  found  in 
the  shells  of  crabs  and  lobsters  a  blue  coloring  matter,  cyanocrystallin,  whicli  turns  red 
Avilh  acids  and  by  boiling  water,  llcematoporphyrin,  according  to  MacjVIunn,-'  also  oc- 
curs in  the  integuments  of  certain  lower  animals. 

In  certain  buttertlies  (the  jiieridinaj)  the  white  pigment  of  the  wings  consists,  as  shown 
by  Hopkins,'  of  uric  acid,  and  the  yellow  ]iignient  of  auric-acid  derivative, /^ptdo^ic  acid, 
which  yields  a  purple  substance,  kpidoporphyrin,  on  warminir  with  dihite  sulphuric  acid. 

In  addition  to  the  coloring  matters  thus  far  mentioned  a  few  others  found  in  certain 
animals  (I hough  not  in  the  skin)  will  be  spoken  of. 

Carminic  acid,  or  the  red  ])igment  of  the  cocliineal,  gives  on  oxidation,  according  to 
LiEBKRMANN  and  VoswiNCKEL,'  cochenilUc  acid,  C10H9O7,  and  cocciiiir  acid, 
CgHs05,  the  first  being  the  tri-carbonic  acid,  and  the  other  the  di-carbonic  acid  of 
m-cresol.  The  beautiful  jiurple  solution  of  ammonium  carminate  lias  two  absorption- 
bands  between  D  and  .£7  which  are  similar  to  those  of  o.\yha;inoglobin.  These  bands  lie 
nearer  to  j&and  closer  together  and  are  less  sharply  defined.  Purple  is  the  evajiorated 
residue  from  the  purple-violet  secretion,  caused  by  the  action  of  the  sunlight,  from  the 

'  Schmiedeberg,  "  Elementarforineln  einiger  Eiweissk5rper,"etc.,  Arch.  f.  exp.  Path, 
u.  Pliarm.,  Bd.  39,  contains  the  analyses  of  other  investigators  as  well  as  the  pertinent 
literature.     See  also  K.  MOrner,  Zeitschr.  f.  physiol.  Chem.,  Bd.  11. 

'  Sieber,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  20;  Abel  and  Davis,  Jouru.  of  Expt. 
Med.,  Vol.  1. 

'  Yergleichend.  physiol.  Studien,  Abtli.  5,  and  (2.  Reihe)  Abth.  1,  S.  151,  Abth.  2,  S. 
1,  and  Abth.  3.  S.  128. 

*  Wurm,  cited  from  Maly's  Jahresher.,  Bd.  1  ;  Halliburton,  Journ.  of  Physiol.,  Vol. 
6 ;  Merejkowski,  Compt.  rend.,  Tome  93  ;  MacMunu,  Proc.  Roy.  Soc,  1883,  and  Journ. 
of  Physiol.,  Vol.  7. 

5  Phil.  Tnins..  Vol.  186. 

*  Ber.  d.  deutsch.  chem.  Gesellsch,,  Bd.  30. 


52Q  THE  SKIN  AND  ITS  SECRETIONS 

so-called  "purple  gland  "of  the  tunic  of  certain  species  of  murex  aud  purpura.     lis 
clieniicid  nature  has  not  been  investigated. 

Among  the  reniaiuing  coloring  matters  found  in  invertebrates  we  may  mention  blue 
stcntorin,  actinioclirom,  bonellin,  polyperythrin,  penteicrinin,  antedo/nn,  crustaceorubin^ 
jiinthiniii,  aud  cJilorophyll. 

Sebum  when  freshly  secreted  is  an  oily  semi-fliiid  mass  which  solidifies 
on  the  upper  surface  of  the  skin,  forming  a  greasy  coating.  The  quantity 
is  very  different  in  different  persons.  IIoppe-Seylee,  has  found  in  the 
sebum  a  body  similar  to  casein  besides  albumin  and  fat.  Cholesterin  is 
also  found  in  this  fat,  and  in  especially  large  quantities  in  the  vernix 
caseosa.  The  solids  of  the  sebum  consist  chiefly  of  fat,  epithelium-cells, 
and  protein  bodies;  the  vernix  caseosa  is  made  up  chiefly  of  fat.  Euppel^ 
found  on  an  average  in  the  vernix  caseosa  348.52  p.  m.  water  and  138.72^ 
p..  m.  ether  extractives.     Besides  cholesterin  he  found  also  isocholesterin. 

On  account  of  the  generally  diffused  view  that  wax  of  the  plant  epider- 
mis serves  as  protection  for  the  inner  parts  of  the  fruit  and  plant, 
LiEBREiCH^  has  suggested  that  the  combinations  of  fatty  acids  with  mona- 
tomic  alcohols  are  the  reason  for  the  resistance  property  of  the  waxes  as 
compared  with  the  glycerin  fats.  He  also  considers  that  the  cholesterin  fats 
play  the  role  of  a  protective  fat  in  the  animal  kingdom,  and  he  has  been 
able  to  detect  cholesterin  fat  in  human  skin  and  air,  in  vernix  caseosa^ 
whalebone,  tortoise-shell,  cow's  horn,  the  feathers  and  beaks  of  several 
birds,  the  prickles  of  the  hedgehog  and  porcupine,  the  hoofs  of  horses,  etc. 
He  draws  the  following  conclusion  from  this,  namely,  that  the  cholesterin 
fats  always  appear  in  combination  with  the  keratinous  substance,  and  that 
the  cholesterin  fat,  like  the  wax  of  plants,  serves  as  protection  for  the  skin- 
surface  of  animals. 

In  the  fatty  protective  substance  secreted  by  the  psylla  alni  Sundvik  '  has  found 
psyllostearyl  ether,  CeoHiauOa  ,  which  splits  on  taking  up  water  into  two  molecules  of  a 
di-valent  alcohol,  psyllostearyl  alcoliol,  CasHesOj . 

Cerumen  is  a  mixture  of  the  secretion  of  the  sebaceous  and  sweat  glands 
of  the  cartilaginous  part  of  the  outer  organs  of  hearing.  It  contains  chiefly 
soaps  and  fat,  and  besides  these  a  red  substance  easily  soluble  in  alcohol  and 
with  a  bitter-SAveet  taste." 

The  preputial   secretion,   smegma  prmptitii,   contains  chiefly  fat,  also 

cholesterin   and   ammonium   soaps,    which    probably   are    produced   from 

decomposed  urine.     The  hippuric  acid,  benzoic  acid,  and  calcium  oxalate 

found  in  the  smegma  of  the  horse  have  probably  the  same  origin. 

We  may  also  consider  as  a  preputial  secretion  the  casioirnm,  which  is  secreted  by  two 
peculiar  glandular  sacs  in  the  prepuce  of  the  beaver.  This  castoreum  is  a  mixture  of 
proteiils,  fat,  resins,  traces  of  phenol  (volatile  oil),  anda  non-uitrogenizedbody,  castorin, 

'  Hoppe-Seyler,  Physiol.  Chem.,  S.  7G0;  Ruppel,  Zeitschr.  f.  physiol.  Chem.,  Bd.  21. 

«  Virchow's  Arch,,  Bd.  121. 

»  Zeitschr.  f.  physiol.  Chem.,  Bdd.  17  and  25. 

*  See  Lamois  aud  Martz,  Maly's  Jahresber.,  Bd.  27,  S.  40. 


SWEAT.  527 

crystallizing  in  four-sided  needles  from  alcohol,  insoluble  in  cold  water,  but  somewhat 
soluble  in  boiling  water,  and  whose  composition  is  little  known. 

In  the  secretion  from  tiie  nnal  j^lands  of  the  skunk  bulyl  morcaptan  and  alkyl  sulphide 
have  been  found  (Aldkich,  E.  Bkckmann  ')• 

Wool-f(Jt,  or  tlie  so-called  faisweat  of  sheep,  is  a  mixture  of  the  secretion  of  the 
sudoriparous  and  sebaceous  glands.  We  find  in  the  watery  extract  a  large  ([uanlity  of 
potassium  which  is  "combined  with  organic  acid,  volatile  and  non-volatile  faity  acids, 
benzoic  acid,  pliennl  sulphuric  acid,  lactic  acid,  malic  acid,  succinic  acid,  and  others. 
Tlie  fat  contains,  among  other  bodies,  abundant  ciuaulities  of  etl.ers  of  fatly  acids  with 
choksieiin  and  isocholesterin.  Daumstadteu  and  LiFscuiJTz''  have  found  other  alco- 
hols in  wool-fat  besides  myristic  acid,  also  two  oxyfatty  acids,  lanoceric  acid,  CsoH«o04, 
and  laniipaliniiic  acid,  C'uHaaOa. 

The  secretion  of  the  coccygeal  glands  of  ducks  and  geese  contains  a  body  similar  to 
casein,  besides  albumin,  nuclein,  lecithin,  and  fat,  but  no  sugar  (De  Jonge).  Poisonous 
bodies  have  been  found  in  the  secretion  of  the  skin  of  the  salamander  and  the  toiid  re- 
spectively, samandarin  (Zaleski,  Faust)  and  bufidin  (Jornaua  and  Casali'). 

The  Sweat.  Of  the  secretions  of  the  skin,  whose  quantity  amounts  to 
about  ^^  of  the  weight  of  the  body,  a  disproportionally  large  part  consists  of 
■water.  Next  to  the  kidneys,  the  skin  in  man  is  the  most  important  means 
for  the  elimination  of  water.  As  the  glands  of  the  skin  and  tlie  kidueya 
stand  near  to  each  other  in  regard  to  their  functions,  they  may  to  a  certain 
extent  act  vicariously  for  one  another. 

The  circumstances  which  influence  the  secretion  of  sweat  are  very 
numerous,  and  the  quantity  of  sweat  secreted  must  consequently  vary  very 
considerably.  The  secretion  differs  for  different  parts  of  the  skin,  and  it 
has  been  stated  that  the  perspiration  of  the  cheek,  that  of  the  palm  of  the 
hand,  and  tiiat  under  the  arm  stand  to  each  other  as  100  :  90  :  45.  From 
the  unequal  secretion  on  different  parts  of  the  body  it  follows  that  no 
results  as  to  the  quantity  of  secretion  for  the  entire  surface  of  the  body  can 
be  calculated  from  the  quantity  secreted  by  a  small  part  of  the  skin  in  a 
given  time.  In  determining  the  total  quantity  a  stronger  secretion  is  as  a 
rule  produced,  and  as  the  glands  can  with  difficulty  work  for  a  long  time 
with  the  same  energy,  it  is  hardly  correct  to  estimate  the  quantity  of  secre- 
tion per  day  from  a  strong  secretion  during  only  a  short  time. 

The  perspiration  obtained  for  investigation  is  never  quite  pure,  but 
contains  cast-off  epidermis-cells,  also  cells  and  fat-globules  from  the 
sebaceous  glands.  Filtered  sweat  is  a  clear,  colorless  fluid  with  a  salty  taste 
and  of  different  odors  from  different  parts  of  the  body.  The  physiological 
reaction  is  acid,  according  to  most  statements.  Under  certain  conditions 
also  an  alkaline  sweat  may  be  secreted  (Trumpy  and  Luchsinger,  Heuss). 
An  alkaline  reaction  may  also  depend  on  a  decomposition  with  the  forma- 
tion of  ammonia.  According  to  a  few  investigators  the  physiological 
reaction  is  alkaline,  and  an  acid  reaction  depends,  according  to  these  inves- 

'  Aldrich,  Journ.  of  Expt.  Med.,  Vol.  1  ;  Beckmaun,  Maly's  Jahresber.,  Bd.  26,  S. 
566. 

«  Ber.  (1.  deutsch.  chem.  Gesellsch.,  Bdd.  29  and  31. 

*  De  Jonge,  Zeitschr.  f.  physiol.  Chem.,  Bd.  3  ;  Zaleski,  Hoppe-Seyler's  Med. -chem. 
Untersuch.,  S.  85;  Faust,  Arch.  f.  exp.  Path.  u.  Pharni.,  Bd.  41;  Jornara  and  CasaU, 
Maly's  Jahresber.,  Bd.  3. 


^28  THE  SKIN  AND  ITS  SECRETIONS. 

tigators,  upoQ  an  admixture  of  fatty  acids  from  the  sebum.  Moriggia 
found  that  the  sweat  from  herbivora  was  ordinarily  alkaline,  while  that 
from  carnivora  was  generally  acid.  According  to  Smith  '  horse's  sweat  is 
strongly  alkaline.     The  specific  gravity  of  human  sweat  is  1.003-1.005. 

Perspiration  contains  977.4-995.6  p.  m.,  average  988.2  p.  m.,  water, 
and  4.4-22.6  p.  m.,  average  11.80  p.  m.,  solids.  The  organic  bodies  are 
neutral  fats,  cholesterin,  volatile  fatty  acids,  traces  of  proteid  (according  to 
Leclerc  and  Smith  always  in  horses,  and  according  to  Gaube  regularly  in 
man,  while  Leube  ^  claims  only  sometimes  after  hot  baths,  in  Bright's 
disease,  and  after  the  use  of  pilocarpin),  also  creatinin  (Oapraxica), 
aromatic  oxyacids,  ethereal-sulphuric  acids  of  lihenol  and  shatoxyl  (Kast'), 
but  not  of  indoxyl,  and  lastly  urea.  The  quantity  of  urea  has  been  deter- 
mined by  Argutinsky.  In  two  steam-bath  experiments,  in  which  in  the 
course  of  -g-  and  f  hour  respectively  he  obtained  225  and  330  c.c.  sweat,  he 
found  1.61  and  1.24  p.  m.  urea.  Of  the  total  nitrogen  of  the  sweat  in 
these  two  experiments  68.5^  and  74.9^  respectively  belong  to  the  urea. 
From  ARGUTiiSrsKY's  experiments,  and  also  from  those  of  Cramer,*  it 
follows  that  of  the  total  nitrogen  a  portion  not  to  be  disregarded  is  elimi- 
nated by  the  sweat.  This  portion  was  indeed  12^  in  an  experiment  of 
Cramer  at  high  temperature  and  powerful  muscular  activity.  Cramer 
has  also  found  ammonia  in  the  sweat.  In  uraemia,  and  in  ischuria  in 
cholera,  urea  may  be  secreted  in  such  quantities  by  the  sweat-glands  that 
crystals  deposit  ujion  the  skin.  The  mineral  bodies  consist  chiefly  of  sodium 
chloride  with  some  potassium  chloride,  alkali  sulphate,  and  phosphate. 
The  relative  quantities  of  these  in  perspiration  differ  materially  from  the 
quantities  in  the  urine  (Favre,^  Kast).  The  relationship,  according  to 
Kast,  is  as  follows: 


Chlorine 

In  perspiration ....  1 

lu  urine 1 


Plaosphate 
0.0015 
0.1320 


Sulphate 
0.009 
0.397 


Kast  found  that  the  proportion  of  ethereal-sulpharic  acid  to  the  sul- 
phate-sulphuric acid  in  sweat  was  1  :  12.  After  the  administration  of 
aromatic  substances  the  ethereal-sulphuric  acid  does  not  increase  to  the 
same  extent  in  the  sweat  as  in  the  urine  (see  Chapter  XV). 

Sugar  may  pass  into  the  sweat  in  diabetes,  but  the  passage  of  the  bile-coloring  matters 
has  not  been  positively  shown  in  this  secretion.     Benzoic  acid,  succinic  acid,  tartaric 

'  Triimpy  and  Luchsinger,  Pfluger's  Arch.,  Bd.  18  ;  Heuss,  Maly's  Jahresber.,  Bd. 
23;  Moriggia,  Mo'eschott's  Untersuch.  zur  Naturlehre,  Bd.  11  ;  Smith,  .Jonrn.  of  Pliys- 
iol.,  Vol.  11.  In  regard  to  the  older  literature  on  sweat  see  Hermann's  Haudbuch,  Bd. 
5,  Till.  1,  S.  421  and  543. 

*  Leclerc,  Compt.  rend.,  Tome  107  ;  Gaube,  Maly's  Jahresber.,  Bd.  22  ;  Leube,  Vir- 
chow's  Arch.,  Bdd.  48  and  50,  and  Arch.  f.  klin.  Med.,  Bd.  7. 

*  Capranica,  Maly's  Jaliresber.,  Bd.  12  ;  Kast,  Zeitschr.  f.  jjhysiol.  Chem.,  Bd.  11. 
''  Argutinsky,  Ptliiger's  Arch.,  Bd.  46  ;  Cramer,  Arch.  f.  Hygiene,  Bd.  10. 

*  Compt.  rend.,  Tome  35,  and  Arch,  gencr.  de  Med.  (5),  Tome  2. 


EXCHANGE  OF  GAS  THROUGH  THE  RKTN.  529 

acid,  iodine,  nrKcuic,  vierruric  rhloride,  and  fjuiniiu'  pass  into  I  lie  s  a  eat.     Unc  acid  Las 
also  been  found  in  the  swciit  in  f:out,  and  cytttin  in  cysiiniira. 

Chrombidrosis  is  tliu  name  given  to  tlie  stcrelioii  of  colored  sweat.  Sometimes  sweat 
lius  been  oliscrvitl  to  be  colored  blue  by  indigo  (Hizio),  by  pyocyanin,  or  b}-  fcrro-pbos- 
pliate  (Kom.mann').  True  blood-sweat,  in  which  blood-corpuscles  exude  from  the 
openings  of  the  glamis,  Lave  also  been  observed. 

The  evchanf/e  of  gas  tit  rough  the  skin  in  man  is  of  very  little  importance 
compared  with  the  exchange  of  gas  by  the  1  tings.  Tlie  absor})tion  of 
oxygen  by  the  skin,  which  was  first  shown  by  Regnault  and  Reiset,  is 
very  small.  The  qimntity  of  carbon  dioxide  eliminated  by  the  skin  increases 
with  tiie  rise  of  temperature  (^Auhekt  Rohhig,  Fubixi  and  Roxcm, 
Baruatt').  It  is  also  greater  in  light  than  in  darkness.  It  i.s  greater 
during  digestion  than  when  fasting,  and  greater  after  a  vegetable  than  after 
an  animal  diet  (Fujuni  and  Roxcni).  The  quantity  calculated  by  various 
investigators  for  the  entire  skin  surface  in  24  hours  varies  between  2.23  and 
32.8  grms.'  In  a  horse,  Zintz  with  Leiimaxn  and  IIagemavn  *  found 
for  24  hours  an  elimination  of  carbon  dioxide  by  the  skin  and  intestine 
■which  amounted  to  nearly  3^  of  the  total  respiration.  Less  than  ^  of  this 
carbon  dioxide  came  from  the  skin  respiration.  According  to  the  same 
investigators  tlie  skin  respiration  equals  2^^  of  the  simultaneous  lung 
respiration. 

As  the  exchange  of  gas  through  the  skin  in  man  and  mammals  is  very 
small,  it  follows  that  the  injurious  and  dangerous  effects  caused  by  covering 
the  skin  with  varnish,  oil,  or  the  like  can  hardly  depend  on  a  reduced 
exchange  of  gas.  After  varnishing  the  skin  there  is  a  considerable  loss  of 
lieat,  and  the  animal  quickly  dies.  If  the  animal,  on  the  contrary,  be 
guarded  from  this  loss  of  heat,  it  may  be  saved,  or  at  least  kept  alive  for  a 
longer  time.  This  effect  was  supposed  to  be  due  to  a  poisoning  caused  by 
a  retention  of  one  or  more  substances  of  the  perspiration  {perspirahile 
retentiim),  accompanied  by  fever  and  increased  loss  of  heat  through  the 
skin;  but  this  statement  has  not  been  substantiated.  This  phenomenon 
seems  to  be  due  to  other  causes,  and  at  least  in  certain  animals  (rabbits) 
death  seems  to  ensue  from  the  paralysis  of  the  vaso-motor  nerves.  In 
anastomosis  the  loss  of  heat  through  the  skin  seems  to  be  increased  to  such 
an  extent  that  the  animal  dies  from  the  lowered  temperature.  According 
to  Laulanie  '  the  animal  dies  of  inanition  because  it  takes  too  little  food, 
while  the  chemical  decomposition  processes  are  greatly  raised  to  cover  the 
loss  of  heat. 

'  Bizzio,  "Wien.  Sitznngsber.,  Bd.  39;  Kollmann,  cited  from  v.  Gorup-Besauez's 
Lebrbuch,  4.  Auti.,  S.  555. 

»  Aubert,  Ptlllger's  Arch..  Bd.  6  ;  R5hrig,  Deutsch.  Klin.,  1872,  S.  209;  Fubini  and 
Ronchi,  Moleschott's  Untersuch.  z.  Naturlehre,  Bd.  12  ;  Barrat,  Journ.  of  Physiol., 
Vol.  21. 

'  See  Hoppe-Seyler,  Physiol.  Chem.,  S.  580. 

*  Du  BoisReymond's  Arch.,  1894,  and  Maly's  Jahresber.,  Bd.  24. 

'  Arch,  de  Physiol.  (5),  Tome  9. 


CHAPTEK  XVII. 

CHEMISTRY   OF  RESPIRATION. 

During  life  a  constant  exchange  of  gases  takes  place  between  thfr 
animal  body  and  the  surrounding  medium.  Oxygen  is  inspired  and  carbon 
dioxide  expired.  This  exchange  of  gases,  which  is  called  respiration,  is 
brought  about  in  man  and  vertebrates  by  the  nutritive  fluids,  blood  and 
lymph,  which  circulate  in  the  body  and  which  are  in  constant  communica- 
tion with  the  outer  medium  on  one  side  and  the  tissue-elements  on  the 
other.  Sach  an  exchange  of  gaseous  constituents  may  take  place  wherever 
the  anatomical  conditions  offer  no  obstacle,  and  in  man  it  may  go  on  in  the 
intestinal  tract,  through  the  skin,  and  in  the  lungs.  As  compared  with 
the  exchange  of  gas  in  the  Inngs,  the  exchange  already  mentioned  which 
occurs  in  the  intestine  and  through  the  skin  is  very  insignificant.  For  this 
reason  we  will  discuss  in  this  chapter  only  the  exchange  of  gas  between  the 
blood  and  the  air  of  the  lungs  on  one  side,  and  the  blood  andTyniph  and 
the  tissues  on  the  other.  The  first  is  often  designated  external  respiration, 
and  the  other  internal  respiration. 

I.  The  Gases  of  the  Blood. 

Since  the  pioneer  investigations  of  Magnus  and  Lothar  Meyer  the 
gases  of  the  blood  have  formed  the  subject  of  repeated,  careful  investiga- 
tions by  prominent  experimenters,  among  whom  we  must  mention  first 
C.  LuDWiG  and  his  pupils  and  E.  Pfluger  and  his  school.  By  these 
investigations  not  only  has  science  been  enriched  by  a  mass  of  facts,  but 
also  the  methods  themselves  have  been  made  more  perfect  and  accurate. 
In  regard  to  these  methods,  as  also  in  regard  to  the  laws  of  the  absorption 
of  gases  by  liquids,  dissociation,  and  related  questions,  the  reader  is  re- 
ferred to  text-books  on  physiology,  on  physics,  and  on  gasometric  analysis. 

The  gases  occurring  in  blood  under  physiological  conditions  are  oxygen, 
carbon  dioxide,  and  nitrogen.  The  last-mentioned  gas  is  found  only  in  very 
small  quantities,  on  an  average  1.8  vols,  per  cent.  The  quantity  is  here, 
as  in  all  following  experiments,  calculated  for  0°  C.  and  760  mm.  pressure. 
The  nitrogen  seems  to  be  simply  absorbed  into  the  blood,  at  least  in  great 
part.  It  appears,  like  argon,  to  play  no  direct  part  in  the  processes  of  lifCj 
and  its  quantity  varies  but  slightly  in  the  blood  of  different  blood-vessels. 

530 


OASES  OF  rilE  BLOOD.  531 

The  oxygen  and  carbon  dioxide  behave  otherwise,  as  their  quantities 
liave  significant  variations,  not  only  in  the  blood  from  dilTerent  blood- 
vessels, but  also  because  many  conditions,  such  as  a  dilTerence  in  the 
rapidity  of  circulation,  a  different  temperature,  rest  and  activity,  cause  a 
change.  In  regard  to  the  gases  they  contain  the  greatest  difference  is 
observable  between  the  blood  of  the  arteries  and  that  of  the  veins. 

The  quantity  of  oxygen  in  the  arterial  blood  of  dogs  is  on  an  uverage 
22  vols,  per  cent  (Pfluger).  In  human  blood  Setsciiexo\v  found  about, 
the  same  quantity,  namely,  21.Gto1s.  per  cent.  Lower  figures  have  been 
found  for  rabbit's  and  bird's  blood,  respectively  13.2^  and  10-lo«^  (Walter, 
Jolyet).  Venous  blood  in  different  vascular  regions  has  very  variable 
quantities  of  oxygen.  By  summarizing  a  great  number  of  analyses  by 
different  experimenters  Zuntz  has  calculated  that  the  venous  blood  of  tiie 
right  side  of  the  heart  contains  on  an  average  7.15^  less  oxygen  than  the 
arterial  blood. 

The  quantity  of  carhon  dioxide  in  the  arterial  blood  (of  dogs)  is  30  to 
40  vols.  ])Qv  cent  (Ludwiu,  Setschenow,  Pfluger,  P.  Bert,  and  otliers), 
most  generally  about  40,<.  Setschenow  found  40.3  vols,  per  cent  in 
human  arterial  blood.  The  quantity  of  carbon  dioxide  in  venous  blood 
varies  still  more  (Ludwig,  Pfluger  and  their  pupils,  P.  Bert,  ^Matiiiix' 
and  Urbain,  and  others).  According  to  the  calculations  of  Zuntz  the 
venous  blood  of  the  right  side  of  the  heart  contains  about  8.2^  more  carbon 
dioxide  than  the  arterial.  The  average  amount  may  be  put  down  as  48 
vols,  per  cent.  Holmgren  found  in  blood  after  asphyxiation  even  G9.2i 
vols,  per  cent  carbon  dioxide.' 

Oxygen  is  absorbed  only  to  a  small  extent  by  the  plasma  or  serum,  in 
which  Pfluger  found  but  0.2G^.  The  greater  part  or  nearly  all  of  the 
oxygen  is  loosely  combined  with  the  hemoglobin.  The  quantity  of  oxygen 
which  is  contained  in  the  blood  of  the  dog  corresponds  closely  to  the 
quantity  which  from  the  activity  of  the  haemoglobin  we  should  expect  to 
combine  with  oxygen,  and  also  the  quantity  of  haemoglobin  in  canine  blood. 
It  is  difllicult  to  ascertain  how  far  the  circulating  arterial  blood  is  saturated 
with  oxygen,  as  immediately  after  bleeding  a  loss  of  oxygen  always  takes 
place.  Still  it  seems  to  be  unquestionable  that  it  is  not  quite  completely 
saturated  with  oxygen  in  life. 

The  carbon  dioxide  of  the  blood  occurs  iu  part,  and  indeed,  according 
to  the  investigations  of  Alex.  Schmidt,^  Zuntz,'  and  L.  FREDERicti,*  to 


'  All  tlic  figures  given  aliove  may  be  found  in  Zuntz's  "Die  Gase  des  Blutes"  ia 
Ilerniiinn's  Ilandhiicli  il.  Pliysiol  .  Bd.  4,  Thl.  2.  S  33-43,  whioli  also  contains  detailed 
statements  and  tlie  pertinent  literature. 

»  Ber.  d.  k.  sachs.  Gesellscli.  d.  Wissensch.,  Mulh.-pliys.  Klasse,  Bd.  19,  1867. 

'  Centralbl.  f.  d.  med.  Wissensch.,  1867,  S.  529. 

*  Recbercbes  sur  la  constitution  du  Plasma  sanguin,  1878,  pp.  50,  51. 


532  CHEMISTRY  OF  RESPIRATION. 

the  extent  of  at  least  one  third,  in  the  blood-corpuscles,  and  also  in  part, 
iind  in  fact  the  greatest  part,  in  tlie  plasma  and  serum  respectively. 

The  carbon  dioxide  of  the  red  corpuscles  is  loosely  combined,  and  the 
constituent  uniting  with  the  CO,  of  the  same  seems  to  be  the  alkali  com- 
bined with  phosphoric  acid,  oxyhaemoglobin  or  haemoglobin,  and  globulin  on 
one  side  and  the  hEemogiobin  itself  on  the  other.  That  in  the  red  corpus- 
cles alkali  phos^^hate  occurs  in  such  quantities  that  it  may  be  of  importance 
in  the  combination  with  carbon  dioxide  is  not  to  be  doubted,  and  we  must 
admit  that  from  the  diphosphate,  by  a  greater  partial  pressure  of  the  carbon 
dioxide,  monophosj)hate  and  alkali  carbonate  are  formed,  while  by  a  lower 
partial  pressure  of  the  carbon  dioxide  the  mass  action  of  the  phospiioric  acid 
comes  again  into  play,  so  that,  with  the  carbon  dioxide  becoming  free,  a 
re-formation  of  alkali  diphosphate  takes  place.  It  is  generally  admitted 
that  the  blood-coloring  matters,  especially  the  oxyhsemoglobin,  which  can 
expel  carbon  dioxide  from  sodium  carbonate  in  vacuo,  act  like  an  acid;  and 
as  the  globulins  also  act  like  acids  (see  below),  these  bodies  may  also  occur 
in  the  blood-corpuscles  as  an  alkali  combination.  The  alkali  of  the  blood- 
corpuscles  must  therefore,  according  to  the  law  of  mass  action,  be  divided 
between  the  carbon  dioxide,  phosphoric  acid,  and  the  other  constituents  of 
the  blood-corpuscles  which  are  considered  as  acid-acting,  and  among  these 
especially  the  blood-pigments,  because  the  globulin  can  hardly  be  of  import- 
ance because  of  its  small  quantity.  By  greater  mass  action  or  greater  partial 
pressure  of  the  carbon  dioxide,  bicarbonate  must  be  formed  at  the  expense 
of  the  diphosphates  and  the  other  alkali  combinations,  while  at  a  diminished 
partial  pressure  of  the  same  gas,  with  the  escape  of  carbon  dioxide,  the 
alkali  diphosphate  and  the  other  alkali  combinations  must  be  re-formed  at 
the  cost  of  the  bicarbonate. 

Haemoglobin  must  nevertheless,  as  the  investigations  of  Setschenow  ' 
and  ZuNTZ,  and  especially  those  of  Bohr  and  Torup,'  have  shown,  be  able 
to  hold  the  carbon  dioxide  loosely  combined  even  in  the  absence  of  alkali. 
Bohr  has  also  found  that  the  dissociation  curve  of  the  carbon-dioxide 
haemoglobin  corresponds  essentially  to  the  curve  of  the  absorption  of  carbon 
dioxide,  on  which  ground  he  and  Torup  consider  the  haemoglobin  itself  as 
of  importance  in  the  binding  of  the  carbon  dioxide  of  the  blood,  and  not  its 
alkali  combinations.  According  to  Bohr  the  haemoglobin  takes  up  the  two 
gases,  oxygen  and  carbon  dioxide,  simultaneously  by  the  oxygen  uniting 
"with  the  pigment  nucleus,  and  the  carbon  dioxide  with  the  proteid  com- 
ponent. 

The  chief  part  of  the  carbon  dioxide  of  the  blood  is  found  in  the  blood- 

'  Ceutralbl.  f.  d.  uied.  Wissensch.,  1877.     See  also  Zuntz  iu  Hermann's  Handbuch, 
8.  76. 

'  Zuntz,  1.  c. ,  S.  7(3  ;  Bolir,  Maly's  Jahrcsber.,  Bd.  17  ;  Torup,  ibid. 


CARBON  DIOXIDE  TX  BLOOD  SERUM.  53:i 

plasma  or  tlie  blood-scrnin,  which  follows  from  the  fact  that  the  serum  is 
richer  in  carbon  dioxide  than  the  corresponding  blood  itself.  By  experi- 
ments with  the  air-pump  on  blood-serum  it  has  been  found  that  the  chief 
part  of  the  carbon  dioxide  contained  in  the  serum  is  given  off  in  a  vacuum, 
while  a  smaller  part  can  be  pumped  out  only  after  the  addition  of  an  acid. 
The  red  corpuscles  also  act  as  an  acid,  and  tlierefore  in  blood  all  the  ciirbon 
dioxide  is  expelled  m  vacuo.  Hence  a  part  of  the  carbon  dioxide  is  firmly 
chemically  combined  in  tlie  serum. 

Absorption  experiments  with  blood-serum  have  shown  ns  further  that 
the  carbon  dioxide  which  can  be  pnmped  out  is  in  great  part  loosely 
chemically  combined,  and  from  this  loose  combination  of  the  carbon  dioxide 
it  necessarily  follows  that  the  serum  must  also  contain  simply  absorbed 
carbon  dioxide.  For  the  form  of  binding  of  the  carbon  dioxide  contained 
in  the  serum  or  the  plasma  we  find  the  three  following  possibilities: 
1.  A  part  of  the  carbon  dioxide  is  simply  absorbed;  2.  Another  part  is 
loosely  chemically  combined;  3.  A  third  part  is  in  firm  chemical  combina- 
tion. 

The  quantity  of  simply  absorbed  carbon  dioxide  has  not  been  exactly 
determined.  Setsciienow  '  considers  the  quantity  in  dog-serum  to  be 
about  -^  of  the  total  quantity  of  carbon  dioxide.  According  to  the  tension 
of  the  carbon  dioxide  in  the  blood  and  its  absorption  coefficient,  the 
quantity  seems  to  be  still  smaller. 

The  quantity  of  firmly  chemically  combined  carbon  dioxide  in  the  blood- 
serum  depends  upon  the  quantity  of  simple  alkali  carbonate  in  the  serum. 
This  quantity  is  not  known,  and  it  cannot  be  determined  either  by  the 
alkalinity  found  by  titration,  nor  can  it  be  calculated  from  the  excess  of 
alkali  found  in  the  ash,  because  the  alkali  is  not  only  combined  with  carbon 
dioxide,  but  also  with  other  bodies,  especially  with  proteid.  The  quantity 
of  firmly  chemically  combined  carbon  dioxide  cannot  be  ascertained  after 
jmniping  out  in  vacuo  without  the  addition  of  acid,  because  to  all  appear- 
ances certain  active  constituents  of  the  serum,  acting  like  acids,  expel  carbon 
dioxide  from  the  simple  carbonate.  The  quantity  of  carbon  dioxide  not 
expelled  from  dog-serum  by  vacuum  alone  without  the  addition  of  acid 
amounts  to  4.9  to  9.3  vols,  per  cent,  according  to  the  determinations  of 
PflCger.' 

From  the  occurrence  of  simple  alkali  carbonates  in  the  blood-serum  it 
naturally  follows  that  a  part  of  the  loosely  combined  carbon  dioxide  of  the 
serum  which  can  be  pumped  out  must  exist  as  bicarbonate.  The  occur- 
rence of  this  combination  in  the  blood-serum  has  also  been  directly  shown. 

'  Centralbl    f.  d.  mod.  "Wissensch.,  1877. 

'  E.  Ptliiger,  Ueber  die  Kohlcnsilure  des  Blutes.  Bonn,  1864.  S.  11.  Cited  from 
Zuutz  in  Hermann's  Handbuch,  S.  65. 


534  CnEMlSTRY  OF  RESPIRATION. 

lu  experiments  "with  the  pump,  as  well  as  in  absorption  experiments,  the 
serum  behaves  in  other  ways  different  from  a  solution  of  bicarbonate,  or 
carbonate  of  a  corresponding  concentration;  and  the  behavior  of  the  loosely 
combined  carbon  dioxide  in  the  serum  can  be  explained  only  by  the  occnr- 
rence  of  bicarbonate  in  the  serum.  By  means  of  vacuum  the  serum  always 
allows  much  more  than  one  half  of  the  carbon  dioxide  to  be  expelled,  and 
it  follows  from  this  that  in  the  pumping  out  not  only  may  a  dissociation  of 
the  bicarbonate  take  place,  but  also  a  conversion  of  the  double  sodium 
carbonate  into  a  simple  salt.  As  we  know  of  no  other  carbon-dioxide  com- 
bination besides  the  bicarbonate  in  the  serum  from  which  the  carbon  dioxide 
can  be  set  free  by  simple  dissociation  in  vacuo,  we  are  obliged  to  assume 
that  the  serum  must  contain  other  faint  acids,  in  addition  to  the  carbon 
dioxide,  which  contend  with  it  for  the  alkalies,  and  which  expel  the  carbon 
dioxide  from  simple  carbonates  in  vacuo.  The  carbon  dioxide  which  is 
expelled  by  means  of  the  pump  and  which,  without  regard  to  the  simple 
absorbed  quantity,  is  generally  designated  as  "  loosely  chemically  combined 
carbon  dioxide,"  is  thus  only  obtained  in  part  in  dissociable  loose  combina- 
tion; in  part  it  originates  from  the  simple  carbonates,  from  which  it  is 
expelled  in  vacuo  by  other  faint  acids. 

These  faint  acids  are  thought  to  be  in  part  phosphoric  acid  and  in  part 
globulins.  The  importance  of  the  alkali  phosphates  for  the  carbon-dioxide 
combination  has  been  shown  by  the  investigations  of  FERiSTET^but  the 
quantity  of  these  salts  in  the  serum  is,  at  least  in  certain  kinds  of  blood, 
for  example  in  ox-serum,  so  small  that  it  can  hardly  be  of  importance.  In 
regard  to  the  globulins  Setschenow  is  of  the  opinion  that  they  do  not  act 
as  acids  themselves,  but  form  a  combination  with  carbon  dioxide,  producing 
carboglobulinic  acid,  which  unites  with  the  alkali.  According  to  Sertoli,' 
whose  views  have  lately  found  a  supporter  in  Torup,  the  globulins  them- 
selves are  the  acids  which  are  combined  with  the  alkali  of  the  blood-serum. 
In  both  cases  the  globulins  would  form,  directly  or  indirectly,  that  chief 
constituent  of  the  plasma  or  of  the  blood-serum  which,  according  to  the  law 
of  the  action  of  masses,  contends  with  the  carbon  dioxide  for  the  alkalies. 
By  a  greater  partial  pressure  of  the  carbon  dioxide  the  latter  deprives  the 
globulin  alkali  of  a  part  of  its  alkali,  and  bicarbonate  is  formed;  by  low 
partial  pressure  the  carbon  dioxide  escapes,  and  the  bicarbonate  is  abstracted 
by  the  globulin  alkali. 

In  the  foregoing  it  has  been  assumed  that  the  alkali  is  the  most  essential 
and  important  constituent  of  the  blood-serum,  as  well  as  of  the  blood  in 
general,  in  uniting  with  the  carbon  dioxide.  The  fact  that  the  quantity  of 
carbon  dioxide  in  the  blood  greatly  diminishes  with  a  decrease  in  the 
quantity  of  alkali  strengthens  this  assumption.     Such  a  condition  is  found, 

'  Hoppe-Seyler,  Med.  clietn.  Untersuch. 


i 


OASES  OF  THE  J  A  Ml' II  AND  SECRETIONS.  535 

for  example,  after  poisoning  with  mineral  acids.  Thus  "Walter  found 
only  2-3  vols,  per  cent  carbon  dioxide  in  the  blood  of  rabbits  into  whose 
stomachs  hydrochloric  acid  had  been  introduced.  In  the  comatose  state  of 
diabetes  mellitus  tlie  alkali  of  the  blood  seems  to  be  in  great  part  saturated 
with  acid  combinations,  y5-oxybutric  acid  (Stadelmanx,  Minkowski), 
and  Minkowski  '  found  only  3.3  vols,  per  cent  carbon  dioxide  in  the  blood 
in  diabetic  coma. 

Oases  of  the  Lymph  and  Secretions. 

The  gases  of  the  lymph  are  the  same  as  in  the  blood-serum,  and  the 
lymph  stands  close  to  the  blood-sernm  in  regard  to  the  quantity  of  the 
various  gases,  as  well  as  to  the  kind  of  carbon-dioxide  combination.  The 
investigations  of  Daenhardt  and  IIensen  '  on  the  gases  of  human  lymph 
are  at  hand,  but  it  still  remains  a  question  whether  the  lymph  investigated 
was  quite  normal.  The  gases  of  normal  dog-lymph  were  first  investigated 
by  Hammarsten.'  These  gases  contained  traces  of  oxygen  and  consisted 
of  37. 4-53. If^  CO,  and  l.G^  N  at  0°  C.  and  7G0  mm.  Ilg  pressure.  About 
one  half  of  the  carbon  dioxide  was  firmly  chemically  combined.  The 
quantity  was  greater  than  in  the  serum  from  arterial  blood,  but  smaller 
than  from  venous  blood. 

The  remarkable  observation  of  Buchner  that  the  lymph  collected  after 
asphyxiation  is  poorer  in  carbon  dioxide  than  that  of  the  breathing  animal 
is  explained  by  Zuntz^  by  the  formation  of  acid  immediately  after  death  in 
the  tissues,  and  especially  in  the  lymphatic  glands,  and  this  acid  decomposes 
the  alkali  carbonates  of  the  lymph  in  part. 

The  secretions  with  the  exception  of  the  saliva,  in  wdiich  Pfluger  and 
KuLZ  found  respectively  0.6^  and  1^  oxygen,  are  nearly  free  from  oxygen. 
The  quantity  of  nitrogen  is  the  same  as  in  blood,  and  the  chief  mass  of  the 
gases  consists  of  carbon  dioxide.  The  quantity  of  this  gas  is  chieily  depend- 
ent upon  the  reaction,  i.e.,  upon  the  quantity  of  alkali.  This  follows  from 
the  analyses  of  Pfluger.  He  found  19^  carbon  dioxide  removable  by  the 
air-pump  and  54'^  firmly  combined  carbon  dioxide  in  a  strongly  alkaline 
bile,  but,  on  the  contrary,  QAV^  carbon  dioxide  removable  by  the  air-pump 
and  0.8^  firmly  combined  carbon  dioxide  in  a  neutral  bile.  Alkaline  saliva 
is  also  very  rich  in  carbon  dioxide.  As  average  for  two  analyses  made  by 
Pfluger  of  the  submaxillary  saliva  of  a  dog  we  have  27. S,'^  carbon  dioxide 
removable  by  the  air-pump  and  47.4^  chemically  combined  carbon  dioxide, 

'  "Walter,  Arch.  f.  exp.  Path.  u.  Pharm..   Bd.  7;  Stadelmaun,  ibid.,  Bd.   17;   Min- 
kowski,  ^littheil.  a.  d.  med.  Klink  iu  Kiinigsberg,  18S8. 
'  Viichow's  Arch.,  Bd.  37. 

*  Ber.  d.  k.  siichs.  Gesellsch.  d.  Wisseuscli.,  math.  phys.  Klasse,  Bd.  23. 

*  Buchner,  Arbeiten  aus  der  physiol.  Anstalt  zu  Leipzig,  1876  ;  Zuutz,  1.  c,  S.  85. 


636  CHEMISTBY  OF  RESPIRATION. 

making  a  total  of  74.9^.  Kulz  '  found  a  maximcim  of  65.78^  carbon 
dioxide  for  the  parotid  saliva,  of  which  3.31^  was  removable  by  the  air- 
pnmp  and  62.47^  was  firmly  chemically  combined.  From  these  and  other 
statements  on  the  quantity  of  carbon  dioxide  removable  by  the  air-pump 
and  chemically  combined  in  the  alkaline  secretions  it  follows  that  bodies 
occur  in  them,  although  not  in  appreciable  quantities,  which  are  analogous 
to  the  albuminous  bodies  of  the  blood-serum  and  which  act  like  faint  acids. 

The  acid  or  at  any  rate  non-alkaline  secretions,  urine  and  milk,  contain, 
on  the  contrary,  considerably  less  carbon  dioxide,  which  is  nearly  all  remov- 
able by  the  air-pump,  and  a  part  seems  to  be  loosely  combined  with  the 
sodium  phosphate.  The  figures  found  by  Pfluger  for  the  total  quantity 
of  carbon  dioxide  in  milk  and  urine  are  10  and  18.1-19.7^  respectively. 

Ewald''  has  made  investigations  on  the  quantity  of  gas  in  pathological 
transudations.  He  found  only  traces,  or  at  least  only  very  insignificant 
quantities,  of  oxygen  in  these  fluids.  The  quantity  of  nitrogen  was  about 
the  same  as  in  blood ;  that  of  carbon  dioxide  was  greater  than  in  the 
lymph  (of  dogs),  and  in  certain  cases  even  greater  than  in  the  blood  after 
asphyxiation  (dog's  blood).  The  tension  of  the  carbon  dioxide  was  greater 
than  in  venous  blood.  In  exudations  the  quantity  of  carbon  dioxide, 
especially  that  firmly  combined,  increases  with  the  age  of  the  fluid,  while, 
on  the  contrary,  the  total  quantity  of  carbon  dioxide,,  and  especially  the 
quantity  firmly  combined,  decreases  with  the  quantity  of  pus-corpuscles. 

II.  The  Exchange  of  Gas  between  the  Blood  on  the 
One  Hand  and  Pulmonary  Air  and  the  Tissues 
on  the  Othero 

In  the  introduction  (Chapter  I,  p.  3)  it  was  stated  that  we  are  to-day  of 
the  opinion,  derived  especially  from  the  researches  of  Pfluger  and  his 
puj)ils,  that  the  oxidations  of  the  animal  body  do  not  take  place  in  the  fluids 
and  juices,  but  are  connected  with  the  form-elements  and  tissues.  It  is 
nevertheless  true  that  oxidations  take  place  in  the  blood,  although  only  to  a 
slight  extent;  but  these  oxidations  depend,  it  seems,  upon  the  form-elements 
of  the  blood,  hence  it  does  not  contradict  the  above  statement  that  the 
oxidations  occur  exclusively  in  the  cells  and  chiefly  in  the  tissues. 

The  gaseous  exchange  in  the  tissues,  which  has  beei\  designated  internal 
respiration,  consists  chiefly  in  that  the  oxygen  passes  from  the  blood  in  the 
capillaries  to  the  tissues,  while  the  great  bulk  of  the  carbon  dioxide  of  the 
tissues  originates  therein  and  passes  into  the  blood  of  the  capillaries.  The 
exchange  of  gas  in  the  lungs,  which  is  called  external  respiration,  consists, 

'  Pfluger,  PflUger's  Arch.,  Bdd.  1  and  2;  Kiilz,  Zeitschr.  f.  physiol.  Chem.,  Bd.  2S. 
It  seems  as  if  Klilz's  results  were  not  calculated  at  760  mm.  Hg,  but  rather  at  1  m. 
«  C.  A.  Ewald,  Arch.  f.  exp.  Anat.  u.  Physiol.,  1873  and  1876. 


i 


DISSOCIATION  OF  OXTIl^-EMOGLOBIN.  ^hl7 

as  we  learn  by  a  comparison  of  tlie  inspired  and  expired  air,  in  the  blood 
taking  oxygen  from  the  air  in  the  lungs  and  giving  off  carbon  dioxide. 
This  does  not  exclude  the  fact  that  in  the  lungs,  as  in  every  other  tissue,  an 
internal  respiration  takes  place,  namely,  a  combustion  with  a  consumption 
of  oxygen  and  formation  of  carbon  dioxide.  According  to  Boiir  and 
HENRKiUEs'  the  lungs  indeed  play  so  large  a  part  in  the  total  metabolism 
that  it  may  amount  to  G8^  of  the  same. 

Wluit  kind  of  processes  take  part  in  this  double  exchange  of  gas?  Is 
the  gaseous  exchange  simply  the  result  of  an  unequal  tension  of  the  blooji 
on  one  side  and  the  air  in  the  lungs  or  tissues  on  the  other?  Do  the  gases 
pass  from  a  place  of  higher  pressure  to  one  of  a  loAver,  according  to  the  laws 
of  diffusion,  or  are  other  forces  and  processes  active  ? 

These  questions  are  closely  related  to  that  of  the  tension  of  the 
oxygen  and  carbon  dioxide  in  the  blood  and  in  the  air  of  the  lungs  and 
tissues. 

Oxygen  occurs  in  the  blood  in  a  disproportionately  large  part  aa 
oxyhfemoglobin,  and  the  law  of  the  dissociation  of  oxyha?moglobin  is  of 
fundamental  importance  in  the  study  of  the  tension  of  the  oxygen  in  the 
blood. 

If  we  recall  that,  accoidirifr  to  Bohr,  what  we  generally  calloxybEemoglobiu  is  a  mix. 
ture  of  lia-moglobins,  which  for  one  iind  the  same  oxygen  pressure  can  uiiile  with  different 
quantities  of  oxygen,  and  also,  as  shown  by  Siegfhi?:d,  that  there  exists,  besides  the 
oxyhaemoglobin,  another  dissociable  oxygen  combinallon  of  haemoglobin,  namely,  pseu- 
dolisemoglobin,  it  seems  that  we  have  several  important  preliminary  questions  to  solve 
before  we  come  to  a  discussion  of  the  dissociation  conditions  of  oxyha'moglobin.  As  the 
above  statements  are  in  part  contradicted  and  in  part  not  sufficiently  proved,  and  as  also, 
according  to  Hufner,  no  difference  exists  between  an  oxyhajmoglobin  solution  and  a 
solution  of  blood-corpuscles  in  regard  to  lis  delivery  of  oxygen,  we  are  jusiitied  in  set- 
ting the  above  statements  aside  for  the  present  and  only  taking  up  the  generally  accepted 
and  authoritative  assertions. 

For  the  understanding  of  the  laws  by  which  the  oxygen  is  taken  up  by 
the  blood  in  the  alveoli  of  the  lungs  the  investigations  on  the  dissociation 
of  oxyhaemoglobin  are  important,  and  those  especially  which  relate  to  the 
dissociation  at  the  temperature  of  the  body  are  of  great  physiological  im- 
portance. vSeveral  investigators  have  experimented  on  this  subject, 
especially  G.  IIufnek.^  He  has  proved  an  important  fact,  namely,  that  a 
freshly  prepared  solution  of  pure  oxyhaemoglobin  crystals  does  not  act  unlike 
freshly  defibrinated  blood  as  regards  the  dissociation  of  oxyhivmoglobin. 
lie  also  showed  that  the  dissociation  is  dependent  upon  the  concentration, 
namely,  that  at  a  given  pressure  a  dilute  solution  is  more  strongly  dis- 
sociated than  a  more  concentrated  solution.  lie  found  for  solutions  con- 
taining 14j^  oxyhaemoglobin  that  the  dissociation  at  +  35°  C.  and  an  oxygen 
partial  pressure  of  75  mm.  Hg  was  only  very  insignificant  and  only  little 

•  Centralbl.  f.  Physiol.,  Bd.  6,  and  Maly's  Jahresber.,  Bd.  27. 

*  Du  Bois-Reymond's  Arch.,  1890,  where  the  older  works  on  the  topic  arc  cited. 


538  CUEMISTRY  OF  RESPIRATION. 

stronger  than  with  a  partial  pressure  of  152  mm.  In  the  first;  instance 
96.S9<^  of  the  total  pigment  was  present  as  oxyhaemoglobin  and  3.11^  as 
hemoglobin,  while  in  the  other  case,  at  152  mm.  pressnre,  the  respective 
fignres  were  98.42^  and  1.58^.  The  dissociation  becomes  stronger  first  with 
an  oxygen  partial  pressnre  of  about  75  mm,  Hg  and  downwards,  and  a 
corresponding  increase  in  the  quantity  of  reduced  hsemoglobin;  but  even 
with  an  oxygen  partial  pressnre  of  50  mm.  Hg  the  quantity  of  haemoglobin 
was  only  4.6^  of  the  total  pigment. 

Erom  these  and  older  researches  by  Hufner,'  which  were  made  at  35° 
or  39°  C,  it  follows  that  the  partial  pressure  of  the  oxygen  may  be  reduced 
to  one  half  of  the  atniospheric  air  without  influencing  essentially  the 
quantity  of  oxygen  in  the  blood  or  a  corresponding  solution  of  oxyhaemo- 
globin. This  corresponds  well  with  the  experience  of  Frakkel  and 
Geppert  '  on  the  action  of  diminished  air-jjressure  on  the  quantity  of 
oxygen  in  the  blood  in  dogs.  With  an  air-pressure  of  410  mm.  Hg  they 
found  the  quantity  of  oxygen  in  arterial  blood  to  be  normal.  With  a 
pressure  of  378-365  mm.  it  was  slightly  diminished,  and  only  on  decreasing 
the  pressure  to  300  mm.  was  the  diminution  considerable. 

We  may  conclude  from  the  large  quantity  of  oxygen  or  oxyhaemo- 
globin in  the  arterial  blood  that  the  tension  of  the  oxygen  in  the  arterial 
blood  must  be  relatively  higher.  From  the  investigations  of  several  experi- 
menters, such  as  P.  Bert,  Herter,^  and  Hufner,  who  expBrimented 
partly  on  living  animals  and  partly  with  hgemogiobin  solutions,  we  may 
assume  the  tension  of  the  oxygen  in  arterial  blood  at  the  temperature  of 
the  body  to  be  equal  to  an  oxygen  partial  pressure  of  75-80  mm.  Hg. 

Let  us  now  compare  these  figures  with  the  tension  of  the  oxygen  in  the 
air  of  the  lungs. 

Numerous  investigations  as  to  the  composition  of  the  inspired  atmos- 
pheric air  as  well  as  the  expired  air  are  at  hand,  and  we  can  say  that  these 
two  kinds  of  air  at  0°  C.  and  a  pressure  of  760  mm.  Hg  have  the  following 
average  composition  in  volume  per  cent: 

Oxygen. 

Atmospheric  air 20.90 

Expired  air 16.03 

The  partial  pressure  of  the  oxygen  of  the  atmospheric  air  corresponds  at 
a  normal  barometric  pressnre  of  760  mm.  to  a  pressure  of  159  mm.  Hg. 
The  loss  of  oxygen  which  the  inspired  air  suffers  in  respiration  amounts  to 
about  4.93^,  while  the  expired  air  contains  about  one  hundred  times  as 
much  carbon  dioxide  as  the  inspired  air. 

'  Du  Bois  Reyraond's  Arch.,  1890. 

'  "Ueber  die  Wirkungen  der  verdilnnten  Lxift  siuf  den  Organisnms."    Berlin,  1883. 
*  Bert,  "  La   pression   baromelrique "   (Paris,    1878)  ;    Hcrler,    Zeitschr.   f.  physiol. 
•Chem.,  Bd.  3. 


Nitrogen. 

Carbon  Dioxide 

79.03 

0.03 

79.59 

4.38 

ALVEOLAR  A  Hi.  539 

The  expired  air  is  therefore  a  mixture  of  alveolar  air  with  the  residue  of 
inspired  air  remaining  in  the  air-passages;  hence  in  the  study  of  the  gaseous 
exchange  in  the  Ir.ngs  we  mnst  first  consider  the  alveohir  air.  We  have  no 
direct  determination  of  the  composition  of  the  alveolar  air,  but  only 
approximate  calculations.  From  the  average  results  found  by  Yierordt  in 
normal  respiration  for  the  carbon  dioxide  in  the  expired  air,  4.G3j^,  Zuntz' 
has  calculated  the  probable  quantity  of  carbon  dioxide  in  the  alveolar  air  as 
equal  to  5.44^.  If  we  start  from  this  value  with  the  assumption  that  the 
quantity  of  nitrogen  in  the  alveolar  air  does  not  essentially  differ  from  the 
expired  air,  and  admit  tliat  the  quantity  of  oxygen  in  the  alveolar  air  is  Q^ 
less  than  the  inspired  air,  we  find  that  the  alveolar  air  contains  l-i.9G< 
oxygen,  corresponding  to  a  partial  pressure  of  114  mm.  Hg. 

We  have  several  direct  determinations  of  the  alveolar  air  of  dogs  by 

Pflugek  and  his  pupils  Wolffberg  and  Xussbaum.'     The  determinations 

which  show  that  the  alveolar  air  is  not  much  richer  in  carbon  dioxide  than 

the  expired   air  have  been   performed   by  means  of   the   so-called    lung- 

'^ntheter. 

The  principle  of  this  nietbod  is  as  folloNvs  :  By  the  iutroductiori  of  a  catlieter  of  a 
special  constnirtion  into  a  branch  of  a  brouolms  the  corresponding  lobe  of  the  lung  may 
be  harnuticaliy  scaled,  while  in  the  other  lobes  of  the  same  lung,  and  in  the  other  lung, 
the  ventilation  remains  unchanged,  so  th;it  no  accuiiuilation  of  carbon  dioxide  takes 
place  ii)  ihe  blood.  When  the  cutting  off  lasts  .so  long  that  a  complete  equalization 
between  the  gases  of  the  blood  and  the  retained  air  of  the  lungs  is  assumed,  a  sample  of 
this  air  of  the  lungs  is  removed  by  means  of  the  catheter  and  analyzed. 

In  the  air  thus  obtained  from  the  lungs  Wolffberg  and  XussBAUjr 
found  an  average  of  3.6<^  CO,.  Xussbaum  has  also  determined  the  carbon- 
dioxide  tension  in  the  blood  from  the  right  heart  in  a  case  simultaneous 
with  the  catheterization  of  the  lungs.  He  found  nearly  identical  results, 
namely,  a  carbon-dioxide  tension  of  3.84^  and  3.81,<  of  an  atmosphere, 
which  also  shows  that  complete  equalization  between  the  gases  of  the  blood 
and  lungs  in  the  enclosed  parts  of  the  lungs  had  taken  place.  From  these 
investigations  we  can  calculate  the  quantity  of  oxygen  in  the  alveolar  air  of 
dogs  to  be  about  16^,  which  corresponds  to  an  oxygen  partial  pressure  of 
about  Vl'l  mm.  llg.  This  pressure  is  considerably  higher  than  tlie  oxygen 
tension  in  arterial  blood,  and  the  oxygen  absorption  from  the  air  of  the 
lungs  takes  place  simply  according  to  the  laws  of  diffusion. 

According  to  Bohr'  the  facts  are  otherwise,  and  the  lungs  are  active 
in  the  taking  up  of  oxygen. 

He  experimented  on  dogs,  allowing  the  blood,  whose  coagulation  had  been  prevented 
by  the  injection  of  peptone  solution  or  infusion  of  the  leech,  to  flow  from  one  bisected 
carotid  to  the  other,  or  from  the  femoral  artery  to  the  femoral  vein,  through  an  ap- 
paratus called  by  him  an  hoemataerometer.     The  apparatus,  which  is  a  modification  of 

>  Zuntz,  1.  c,  S.  105  and  106. 

*  Wolffberg,  Ptluger's  Arch.,  Bd.  6  ;  Xussbaum,  ibid.,  Bd.  7. 

»  Skand.  Arch.  f.  Physiol.,  Bd.  2. 


640  CHEMISTRY  OF  RESPIRATION. 

Ludwig's  rheometcr  (stromubr),  allowed,  according  to  Bonn,  of  a  complete  interchange 
between  the  gases  of  the  blood  circulating  through  the  apparatus  and  a  quantity  of  gas 
whose  composition  was  known  at  the  beginning  of  the  experiment  and  enclosed  in  the 
apparatus.  The  mixture  of  gases  was  analyzed  after  an  equalization  of  the  ga^es  by 
diffusion.  In  this  way  the  tension  of  the  oxygen  and  carbon  dioxide  in  the  circulating 
arterial  blood  was  determined.  During  the  experiment  the  composition  of  the  inspired 
and  expired  air  was  also  determined,  the  number  of  inspirations  noted,  and  the  extent 
of  respirator}'  exchange  of  gas  measured.  To  be  able  to  make  comparison  between  the  gas- 
tension  in  the  blood  and  in  an  expired  air  whose  composition  was  closer  to  the  unknown 
composition  of  the  alveolar  air  than  the  ordinary  expired  air,  the  composition  of  the  ex- 
pired air  at  the  moment  it  passed  the  bifurcation  of  the  trachea  was  ascertained  by 
special  calculation.  The  tension  of  the  gases  in  this  "  bifurcated  air"  could  be  com- 
pared with  the  tension  of  the  gases  of  the  blood,  and  in  such  a  way  that  the  compan 
son  took  place  simultaneously. 

Bohr  foand  remarkably  liigli  resalts  for  the  oxygen  tension  in  arterial 
blood  in  this  series  of  experiments.  They  varied  between  101  and  1-14  mm. 
Hg  pressure.  In  eight  otit  of  nine  experiments  on  the  breathing  of  atmos- 
pheric acid,  and  in  four  out  of  live  experiments  on  breathing  air  containing 
carbon  dioxide,  the  oxygen  tension  in  the  arterial  blood  was  higher  than 
the  "  bifarcated  air."  The  greatest  difference,  Avhere  the  oxygen  tension 
was  higher  in  the  blood  than  in  the  air  of  the  lungs,  was  38  mm.  Hg. 

According  to  Bohr  we  cannot  simply  explain  the  taking  up  of  oxygen 
by  the  blood  from  the  air  of  the  lungs  by  a  higher  partial  pressure  of  the 
oxygen.  The  difference  in  tension  between  the  two  sides  of  the  walls  of 
the  alveoli  therefore  may  not  be  the  only  force  which  serves  in  the 
migration  of  the  oxygen  through  the  lung  tissue,  and  the  kmgs  them- 
selves must  exercise  an  unknown  specific  action  in  the  taking  up  of 
oxygen. 

HuFNER  and  Fredericq  '  have  made  the  objection  to  Bohr's  experi- 
ments and  views  that  a  perfect  equilibrium  had  probably  not  been  attained 
between  the  air  in  the  apparatus  and  the  gases  of  the  blood.  Fredericq, 
by  new  experiments,  has  presented  strong  objections  to  the  acceptance  of 
Bohr's  findings.  On  the  other  hand  Haldane  and  Smith's"  recent 
experiments  upon  an  entirely  different  principle  show  results  which  con- 
tradict the  ordinary  doctrine  of  the  oxygen  absorption  in  the  1  tings. 

Haldane's  method  is  as  follows  :  The  individual  experimented  \ipon  is  allowed  to 
inspire  air  containing  an  exactly  known  but  small  quantity  of  carbon  monoxide  (0.045 
—  0.06  percent),  until  no  further  ab.sorption  of  carbon  monoxide  takes  place  and  until  the 
percentage  saturation  of  tlie  hiemoglobin  in  the  arterial  blood  witli  carbon  monoxide  lias 
become  constant  as  .shown  by  a  special  titration  method.  This  percentaae  saturation  is 
dependent  upon  tiie  relation  between  the  tension  of  the  oxygen  in  the  blood  and  the 
tension  of  the  carbon  monoxide,  as  known  from  tiie  composition  of  the  inspired  air, 
When  this  last  and  the  percentage  saturation  with  carbon  monoxide  and  oxygen  are 
known  the  oxygen  tension  in  the  blood  can  be  easily  calculated. 

Haldane  and  Smith  calculate  the  tension  of  the  oxygen  in  arterial 
human  blood  at  an  average  of  20.2^  of  an  atmosphere,  i.e.,  equal  approxi- 

■  Hllfner,  Du  Bois-Reymond's  Arch.,  1890;  Fredericq,  Centralbl.  f.  Physiol.,  Bd.  7, 
and  Travaux  du  laboratoire  de  I'institut  de  ph^'siologie  de  Lifige,  Tome  5,  1896. 
'  Ilaldane,  Journ.  of  Physiol.,  Vol.  18,  Haldane  and  Smith,  ibid.,  Vol.  20. 


CARBON  DIOXIDE  TENSION.  TAl 

mately  to  200  mm.  Ily.     In  agreement  witli  Hoini  tlie  view  is  lield  that 

diffusion  ulone  cannot  explain  tlie  passage  of  oxygen  from  the  lungs  to  the 

blood,  and  that  this  question  requires  further  investigation. 

As  llie  li;umo!,'lol)iii  obtiuiicd  from  different  blood  portions  does  not,  according  to 
Bonu,  jihvnys  take  up  tlie  siune  quiiniit}'  of  oxygen  for  eiieli  grninme,  so,  tlie  liaenio- 
gloliin  within  the  blood-corpuscle  nuiy  show  a  siniilur  behuvior.  He  calls  ilie  qujin- 
tity  of  oxygen  (ineasurod  at  0°  C.  and  760  mm.  Ilg)  which  is  taken  up  by  1  grm. 
liaemoglobin  of  tlie  blood  at  l.j°  C.  and  an  oxygen  luessure  of  l')0  nun.  tlie  npirifie  oxy- 
ffen  nipdciti/.^  This  (piantiiy,  he  claims,  may  be  diJl'iient  not  only  in  dillerent  indi- 
viduals, but  also  in  the  dillerent  vascular  systems  of  the  same  animal,  and  it  may 
also  be  changed  experimentally  by  bleeding,  breathint;  air  deficient  in  oxygen,  or  poison- 
ing. It  is  now  evident  that  one  and  the  same  ijuaulity  of  oxygen  in  the  blood,  other 
things  being  e(iual,  must  have  a  different  tension  according  as  the  specific  oxygen  ca- 
pacity is  greater  or  smaller.  The  tension  of  the  o.xygen,  Bonn  says,  may  be  changed 
without  changing  the  (piantily  of  oxygen,  and  the  animal  body  must,  according 
to  him,  have  means  of  varying  the  tension  of  the  oxygen  in  the  tissiU'S  in  a  short 
time  -without  changing  the  quantity  of  oxygen  contained  iu  tlie  blood.  The  great  im- 
portance of  such  a  property  of  the  tissues  for  respiration  is  evident ;  but  it  is  perhaps  too 
early  to  give  a  positive  opinion  on  Boiiu's  statements  and  experiments. 

The  tension  of  the  carbon  dioxide  in  the  blood  has  been  determined  in 
different  ways  by  Pfluger  and  his  pupils,  Wolffberg,  Strassburg,  and 

XUSSBAUM.' 

According  to  the  aerotonometric  method  the  blood  is  allowed  to  flow  directly  from 
the  artery  or  vein  through  a  glass  tube  which  contains  a  gas  mixture  of  a  known  com- 
position. If  the  tension  of  the  carbon  dioxide  in  the  blood  is  greater  than  the  gas  mix- 
ture, then  the  blood  gives  up  carbon  dioxide,  while  in  the  reverse  case  it  takes  up  carbon 
dioxide  from  the  gas  mixture.  The  analysis  of  the  gas  mixture  after  pa.ssing  tlie  blood 
through  it  will  al.so  decide  if  the  tension  of  the  carbon  dioxide  in  the  blood  is  greater 
or  less  than  in  the  gas  mixture  ;  and  by  a  sufficiently  great  number  of  determinations, 
especially  when  the  (juantity  of  carbon  dioxide  of  the  gas  mixture  corresponds  as  nearly 
as  possible  in  the  beginning  to  the  probable  tension  of  this  gas  in  the  blood,  we  may 
learn  the  tension  of  the  carbon  dioxide  in  the  blood. 

According  to  this  method  the  carbon-dioxide  tension  of  the  arterial 
blood  is  on  an  average  2.85^  of  an  atmosphere,  corresponding  to  a  pressure 
of  21  mm.  mercury  (Strassburg).  In  the  blood  from  the  pulmonary 
alveoli  Nussbaum  found  a  carbon-dioxide  tension  of  3.81^  of  an  atmos- 
phere, corresponding  to  a  pressure  of  28.95  mm.  mercury.  Strassburg, 
who  experimented  in  tracheotomized  dogs  in  which  the  ventilation  of  the 
lungs  was  less  active  and  therefore  the  carbon  dioxide  was  removed  from  the 
blood  with  less  readiness,  found  in  the  venous  blood  of  the  heart  a  carbon- 
dioxide  tension  of  5.4^  of  an  atmosphere,  corresponding  to  a  partial  pressure 
of  41.01  mm.  mercury. 

Another  method  is  the  catheterization  of  a  lobe  of  the  lungs  (see  page 
539).  In  the  air  thus  obtained  from  the  lungs  Nussbaum  and  Wolffberg 
found  an  average  of  3.6^  CO,.  Kussbaum,  as  previously  mentioned,  has 
also  determined  the  carbon-dioxide  tension  in  the  blood  of  the  pulmonary 
alveoli  in  a  case  simultaneously  with  the  catheterization  of  the  lungs.  He 
found  nearly  identical  results,  namely,  a  carbon-dioxide  tension  of  3.84j^ 
and  3.81^. 

>  Bohr,  Centralbl.  f.  Physiol.,  Bd.  4. 

*  Wolffberg,  Ptlilger's  Arch.,  Bd.  6  ;  Strassbing,  ibid.;  Nussbaum,  ibid.,  Bd,  7. 


542  CnEMISTRY  OF  REtiPIllATlON. 

BoiiK,  in  liis  experiments  above  mentioned  (page  539),  has  arrived  at 
other  resnlts  in  regard  to  the  carbon-dioxide  tension.  In  eleven  experiments 
with  inhahition  of  atmospheric  air  the  carbon-dioxide  tension  in  the  arterial 
blood  varied  from  0  to  38  mm.  Hg,  and  in  five  experiments  with  inhalation 
of  air  containing  carbon  dioxide  from  0.9  to  57.8  mm.  Hg.  A  comparison 
of  the  carbon-dioxide  tension  in  the  blood  with  the  bifurcated  air  gave  in 
several  cases  a  greater  carbon-dioxide  pressure  in  the  air  of  the  lungs  than 
in  the  blood,  and  as  maximum  this  difference  amounted  to  17.2  mm.  in 
favor  of  the  air  of  the  lungs  in  the  experiments  with  inhalation  of  atmo- 
spheric air.  As  the  alveolar  air  is  richer  in  carbon  dioxide  than  the  bifur- 
cated air,  this  experiment  unquestionably  proves,  according  to  Bohr,  that 
the  carbon  dioxide  has  migrated  against  the  high  pressure. 

In  opposition  to  these  investigations,  Fredericq,'  in  his  above-mentioned 
experiments,  obtained  the  same  figures  for  the  carbon-dioxide  tension  in 
arterial  peptone  blood  as  Pelugee.  and  his  pupils  found  for  normal  blood. 
Weisgerber,"  in  Fredericq's  laboratory,  has  made  experiments  with 
animals  which  respired  air  rich  in  carbon  dioxide,  and  these  experiments 
confirm  Pfluger's  theory  of  respiration.  The  low  figures  obtained  by 
Bohr  for  the  carbon-dioxide  tension  appear  remarkable  when  we  recall  that 
GRA.XDIS  found  in  peptone  blood  which  Lahousse  and  Blachsteix' had 
shown  was  poor  in  carbon  dioxide,  a  high  carbon-dioxide  tension. 

A  certain  importance  has  been  ascribed  to  oxygen  in  re'ga^d  to  the 
elimination  of  carbon  dioxide  in  the  lungs,  in  that  it  has  an  expelling  action 
on  the  carbon  dioxide  from  its  combinations  in  the  blood.  This  statement, 
first  made  by  Holmgren,  has  recently  found  an  advocate  in  Werigo.* 
This  investigator  has  made  ingenious  experiments  on  living  animals  in  which 
he  allows  both  lungs  of  the  animal  to  breathe  sejDarately,  the  one  with 
hydrogen  and  the  other  with  pure  oxygen  or  a  gas  mixture  rich  in  oxj^gen. 
He  invariably  found  a  greater  carbon-dioxide  tension  in  the  air  sucked  from 
the  lungs  in  the  presence  of  oxygen,  and  he  draws  the  conclusion  from  his 
experiments  that  the  oxygen  passing  from  the  lung  alveoli  into  the  blood 
raises  the  carbon-dioxide  tension.  According  to  Werigo,  by  this  action 
the  oxygen  is  a  powerful  factor  in  the  elimination  of  carbon  dioxide,  and 
therefore  it  is  not  necessary  to  assume  a  specific  action  of  the  lung  itself  in 
these  processes. 

ZuxTZ '  has  suggested  important  objections  to  the  conclusions  of 
Werigo,  but  they  have  not  been  substantiated  by  experiment;  hence  the 
question  is  still  open. 

'  See  foot-note  1,  page  540. 
»  Ceiitralbl.  f.  Physiol.,  Bd.  10,  S.  482. 

*  Graudis,  Du  Bois-Reymond's  ArcL.,  1891  ;  Laliousse,  ibid.,  1889  ;  Blacbsteiu,  ibid.^ 
1891. 

••  Holmgren,  Wiener  Sitzungsber. ,  Bd.  48  ;  Werigo,  Pfluger's  Arch.,  Bdd.  51  and  52l 
'  Ihid.,  Bd.  52, 


INTERNAL  RESPIRATION.  f54.^ 

We  are  not  quite  clear  in  regard  to  the  carbon-dioxide  elimination 
in  the  lungs,  and  we  must  wait  for  further  light  on  this  head. 

From  what  has  been  said  above  (page  53G)  in  regard  to  the  internal 
respiration  we  conclude  that  it  consists  chiefly  in  that  in  the  capillaries  the 
oxygen  passes  from  the  blood  into  the  tissues,  while  the  carbon  dioxide 
passes  from  the  tissues  into  the  blood. 

Tiie  assertion  of  Estor  and  Saint  Pierre  that  the  quantity  of  oxygen 
in  the  blood  of  the  arteries  decreases  with  the  remoteness  from  the  heart 
has  been  shown  as  incorrect  by  Pfluger,'  and  the  oxygen  tension  in  the 
blood  on  entering  the  capillaries  must  be  higher.  As  compared  with  the 
capillaries  the  tissues  are  to  be  considered  as  nearly  or  entirely  free  from 
oxygen,  and  in  regard  to  the  oxygen  a  considerable  difference  in  pressure 
must  exist  between  the  blood  and  tissues.  The  possibility  that  this  differ- 
ence in  pressure  is  sufficient  to  supply  the  tissues  with  the  necessary 
quantity  of  oxygen  is  hardly  to  be  doubted. 

In  regard  to  the  carbon-dioxide  tension  in  the  tissue  we  must  assume 
a  priori  that  it  is  higher  than  in  the  blood.  This  is  found  to  be  true. 
Strassburg  '  found  in  the  urine  of  dogs  and  in  the  bile  a  carbon-dioxide 
tension  of  9^  and  7^  of  an  atmosphere,  respectively.  The  same  experi- 
menter has,  further,  injected  atmospheric  air  into  a  ligatured  portion  of  the 
intestine  of  a  living  dog  and  analyzed  the  air  taken  out  after  some  time. 
He  found  a  carbon-dioxide  tension  of  7.7fo  of  an  atmosphere.  The  carbon- 
dioxide  tension  in  the  tissues  is  considerably  greater  than  in  the  venous 
blood,  and  there  is  no  opposition  to  the  view  that  the  carbon  dioxide  simply 
diffuses  from  the  tissues  to  the  blood  according  to  the  laws  of  diffusion. 

That  a  true  secretion  of  gases  occurs  in  animals  follows  from  the  composition  and 
beliavior  of  the  gases  in  the  swimming-bliidder  of  fishes.  These  gases  consist  of  oxj'- 
gen  ami  nitrogen  with  only  small  quantities  of  carbon  dioxide.  In  tislics  which  do  not 
live  at  any  great  depth  the  quantity  of  oxygen  is  ordinarily  as  high  as  in  the  atmos- 
phere, while  fishes  which  live  at  great  depths  may,  according  to  BioT  and  others,  con- 
tain considerably  more  oxygen  and  even  above  80$?.  Moreau  has  also  found  that  after 
emptying  the  swimming-bladder  by  means  of  a  trocar  new  air  collected  after  a  t.me, 
and  this  air  was  richer  in  oxygen  than  the  atmospheric  air  and  contained  even  85!? 
oxygen.  Bohr.*  who  has  proved  and  confirmed  these  statements,  also  found  that  this 
collodion  is  under  the  influence  of  the  nervous  system,  because  on  the  section  of  certain 
branches  of  pneuniogastric  nerve  it  is  tiiscontinued.  It  is  beyond  dispute  that  we  have 
here  a  secretion  and  not  a  diffusion  of  oxygen. 

Several  methods  have  been  suggested  for  the  study  of  the  quantitative 
relationship  of  the  respiratory  exchange  of  gas.  We  must  refer  the  reader 
to  other  text-books  for  more  details  of  these  methods,  and  we  will  here  only 
mention  the  chief  features  of  the  most  important  methods. 

'  Estor  and  St.  Pierre  witii  Pflilger  in  PflUger's  Arch.,  Bd.  1. 

»  Pfliiger's  Arch.,  Bd.  6. 

'  Biot,  see  Hermann's  Ilandbuch  d.  Physiol.,  Bd.  4,  Thl.  2,  S.  lol  ;  Moreau.  Compt. 
rend..  Tome  57  ;  Bohr,  Journ.  of  Physiol.,  Vol,  15.  See  also  IlQfner,  Du  Bois-Rey.. 
mond's  Arch.,  1893. 


644  CHEMISTRY  OF  RESPIRATION. 

REGNAt'LT  and  Reiset's  Method.  According  to  this  method  the  animal  or  person 
experimented  upon  is  allowed  to  bieutbe  in  an  enclosed  space.  The  carbon  dioxide  is 
removed  from  the  air,  as  it  forms,  by  strong  caustic  alkali,  from  which  the  quantity 
may  be  determined,  while  the  oxygen  is  replaced  continually  b}'  exactly  measured 
quantities.  This  method,  which  also  makes  possible  a  direct  determination  of  the 
oxygen  used  as  well  as  the  carbon  dioxide  produced,  has  since  been  moditied  by  other 
invcsiigntors,  such  as  Pfluger  and  his  pupils,  Seegen  and  Nowak,  and  Hoppe- 
Seylek,' 

PErxENKOPER's  Method.  According  to  this  method  the  individual  to  be  experi- 
mented upon  breathes  in  a  room  through  which  a  current  of  atmospheric  air  is  passed. 
The  quantity  of  air  passed  through  is  carefully  measured.  As  it  is  impossible  to 
analyze  all  the  air  made  to  pass  through  the  chamber,  a  small  fraction  of  this  air  is 
diverted  into  a  brunch  line  during  the  entire  experiment,  carefully'  measured,  and  the 
quantit}^  of  carbon  dioxide  and  water  determined.  From  the  composition  of  this  air 
the  quantity  of  water  and  carbon  dioxide  contained  in  the  large  quantity  of  air  made  to 
pass  throui^h  the  chamber  can  be  calculated.  The  consumption  of  oxygen  cannot  be 
directly  determined  in  this  method,  but  may  be  indirectly  by  difference,  which  is  a 
defect  in  this  method.  The  large  respiration  apparatus  of  Sokden  and  Tigekstedt^ 
is  based  uj^ou  this  principle. 

Speck's  Method.^  For  briefer  experiments  on  man  Speck  has  used  the  following: 
He  breathes  into  two  spirometer-receivers,  on  which  the  gas-volume  can  be  read  oif 
very  accurately,  through  a  mouthpiece  with  two  valves,  closing  the  nose  with  a  clamp. 
The  air  from  one  of  the  spirometers  is  inhaled  through  one  valve,  and  the  expired  air 
passes  through  the  other  into  the  other  spirometer.  By  means  of  a  rubber  tube  con- 
nected with  the  expiration-tube  an  accurately  measured  part  of  the  expired  air  may  be 
passed  into  an  absorption-tube  and  analyzed. 

ZuNTz  and  Geppert's  Method.*  This  method,  which  has  been  improved  by  Zuntz 
and  his  pupils  from  time  to  time,  consists  in  the  following:  The  individual  being 
experimented  upon  inspires  pure  atmospheric  air  through  a  very  wide  feed-pipe  leading 
from  the  open  air,  the  inspired  and  the  expired  air  being  separated  by  two  valves 
(human  .subjects  breathe  with  closed  nose  by  means  of  a  soft  rubber  mouthpiece,  ani- 
mals througli  an  air-tight  tracheal  canuLi).  The  volume  of  the  expired  air  is  measured 
by  a  gas-meter,  and  an  aliquot  part  of  this  air  collected  and  the  quantTtyX)f  carbon 
dioxide  and  oxygen  determined.  As  the  composition  of  the  atmospheric  air  can  be 
considered  as  constant  within  a  certain  limit,  the  production  of  carbon  dioxide  as  well 
as  the  consumption  of  oxygen  may  be  readily  calculated  (see  the  works  of  Zuntz  and 
his  pupils). 

Hanriot  and  Richet's  method^  is  characterized  by  its  simplicity.  These  investi- 
gators allow  the  total  air  to  pass  through  three  gas-m'eters,  one  after  the  other.  The 
tirst  measures  the  inspired  air,  whose  composition  is  known.  The  second  gas-meter 
measures  the  expired  air,  and  the  third  the  quantity  of  the  expired  air  after  the  carbon 
dioxide  has  been  removed  by  a  suitable  apparatus.  The  quantity  of  carbon  dioxide 
produced  and  the  oxygen  consumed  can  be  readily  calculated  from  these  data. 

Appendix. 

The  Lungs  and  their  Expectorations. 
Besides  proteid  bodies  and  the  albuminoids  of  the  connective-substance 
group,  lecithin,  taurin  (especially  in  ox-lnngs),  ^iric  acid,  and  inosit  have 
been  found  in  the  lungs.     Poulet*  claims  to  have  found  a  special  acid, 

'  See  Zuntz  in  Hermann's  Handbuch,  Bd.  4,  Thl.  2,  and  Hoppe-Seyler,  Zeitschr.  f 
physiol.  Chem.,  Bd.  19. 

■^  Pettenkofer's  method;  see  Zuntz,  1.  c. ;  Sonden  and  Tigerstedt,  Skand.  Arch.  f. 
Physiol  ,  Bd.  G. 

'  Speck,  Piiysiologie  des  menschlichen  Athmens.     Leipzig,  1892. 

*  Pfllig'-r's  Arch.,  Bd.  42.  See  also  Magnus-Levy  in  Ptliiger's  Arch.,  Bd.  55,  S.  10, 
in  which  the  work  of  Zuntz  and  his  pupils  is  cited. 

^  Compt.  rend.,  Tome  104. 

•  Cited  from  Maly's  Jahresber.,  Bd.  18,  S.  248. 


LUNQS  AND   TIIETR  EXPECTORATIONS.  545 

which   he  lias  called   pulmotartaric  acid,   in    the  lung-tissue.       Glycogen 
(Dccnrs  abundantly  in  the  embryonic  lung,  but  is  absent  in  the  adult  lung. 

The  black  or  dark  brown  pigment  In  the  lungs  of  human  beings  and  domestic  ani- 
mals consists  chiefly  of  carbon,  which  originates  from  the  soot  in  the  air.  The  pigmt;nt 
may  in  part  also  cfOnsist  of  melanin.  Besides  carbon,  otlier  bodies,  such  as  iron  o.\ide, 
silicic  acid,  and  clay,  may  be  deposited  in  the  lungs,  being  inhaled  as  dust. 

Among  the  bodies  found  in  the  lungs  under  pathological  conditions  we 
must  specially  mention  albumoees  and  peptones  (in  pneumonia  and  suppura- 
tion), glycogen,  a  faintly  dextro-rotatory  carbohydrate  differing  from 
glycogen  found  by  Pouchet  in  consumptives,  and  finally  also  cellulose, 
which,  according  to  Freund,'  occurs  in  the  lungs,  blood,  and  pas  of 
persons  with  tuberculosis. 

C.  W.  Schmidt  found  in  1000  grma.  mineral  bodies  from  the  normal 
human  lung  the  following:  NaCl  130,  K,0  13,  Na,0  195,  CaO  19,  MgO 
19,  Fe^O,  3-2,  P,0,  485,  SO,  8,  and  sand  134  grms.  According  to 
Oidtmaxn'  the  lungs  of  a  14-day-old  child  contained  79G.05  p.  m.  water, 
198.19  p.  m.  organic  bodies,  and  5. 7G  p.  m.  inorganic  bodies. 

The  sputum  is  a  mixture  of  the  mucous  secretion  of  the  respiratory 
passages,  of  saliva  and  buccal  mucus.  Because  of  this  its  composition  is 
very  variable,  especially  under  pathological  conditions  when  various  products 
mix  with  it.  The  chemical  constituents  are,  besides  the  mineral  substances, 
chiefly  mucin  with  a  little  proteid  and  nuclein  substance.  Under  patho- 
logical conditions  albumoses  and  peptone  (?),  volatile  fatty  acids,  glycogen, 
Charcot's  crystals,  and  also  crystals  of  cholesterin,  hrematoidin,  tyrosin, 
fat  and  fatty  acids,  triple  phosphates,  etc.,  have  been  found. 

The  form  constituents  are,  under  physiological  circumstances,  epithe- 
lium-cells of  various  kinds,  leucocytes,  sometimes  also  red  blood-corpuscles 
and  various  kinds  of  fungi.  In  pathological  conditions  elastic  fibres,  spiral 
formations  consisting  of  a  mucin-like  substance,  fibrin  coagulum,  pus, 
pathogenic  microbes  of  various  kinds,  and  the  above-mentioned  crystals 
occur. 

'  Pouchet,  Compt.  rend.,  Tome  96  ;  Freund,  cited  from  Maly's  Jahresber.,  Bd.  16, 
S.  471. 

"  Schmidt,  cited  from  v.  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  737  ;  Oidtmann, 
ibid.,  S.  732. 


CHAPTER  XVIIL 

METABOLISM  WITH  VARIOUS  FOODS,   AND  THEIR  NECESSITY 

TO  MAN. 

The  conversion  of  chemical  tension  into  living  energy,  which  character- 
izes animal  life,  leads,  as  previously  stated  in  Chapter  I,  to  the  formation  of 
relatively  simple  compounds — carbon  dioxide,  urea,  etc. — which  leave  the 
organism,  and  which,  moreover,  being  very  poor  in  potential  energy,  are 
for  this  reason  of  no  or  very  little  value  for  the  body.  It  is  therefore 
absolutely  necessary  for  the  continuance  of  life  and  the  normal  course  of  the 
functions  of  the  body  that  the  organism  and  its  different  tissues  should  be 
supplied  with  new  material  to  replace  that  which  has  been  exhausted.  This 
is  accomplished  by  means  of  food.  Those  bodies  are  designated  as  food 
whicli  have  no  injurious  action  upon  the  organism  and  which  serve  as  a 
source  of  energy  and  can  replace  those  constituents  of  the  body^hat  have 
been  consumed  in  metabolism  or  that  can  prevent  or  diminish  the  con- 
sumption of  such  constituents. 

Among  the  numerous  dissimilar  substances  which  man  and  animals  take 
with  the  food  all  cannot  be  equally  necessary  or  have  the  same  value.  Some 
perhaps  are  unnecessary,  while  others  may  be  indispensable.  We  have 
learned  by  direct  observation  and  a  wide  experience  that  besides  the  oxygen, 
which  is  necessary  for  oxidation,  the  essential  foods  for  animals  in  general, 
and  for  man  especially,  are  water,  mineral  bodies,  proteins,  carbohydrates, 
and  fats. 

It  is  also  apparent  that  the  various  groups  of  food-stuffs  necessary  for 
the  tissues  and  organs  mast  be  of  varying  importance;  thus,  for  instance, 
water  and  the  mineral  bodies  have  another  value  tlian  the  organic  foods, 
and  these  again  must  differ  in  importance  among  themselves.  The  knowl- 
edge of  the  action  of  various  nutritive  bodies  on  the  exchange  of  material 
from  a  qualitative  as  well  as  a  quantitative  point  of  view  must  be  of  funda- 
mental importance  in  determining  the  value  of  different  nutritive  substances 
relative  to  the  demands  of  the  body  for  food  under  various  conditions,  and 
also  in  deciding  many  other  questions — for  instance,  the  proper  nutrition 
for  an  individual  in  health  and  in  disease. 

Such  knowledge  can  only  be  attained  by  a  series  of  systematic  and 
thorough  observations,  in  which  the  quantity  of  nutritive  material,  relative 

546 


EXCRETA   OF  2UIE  ORGANISM.  547 

to  tlie  weiglit  of  the  body,  taken  and  absorbed  in  a  given  time  is  compared 
with  the  quantity  of  final  metabolic  products  which  leave  the  organism  at 
the  same  time,  liesearches  of  this  kind  have  been  made  by  sceral  in\esti- 
gators,  but  above  all  should  be  mentioned  those  made  by  Bisciioff  and 
VoiT,  by  Pkttexkofkk  and  Voit,  and  by  VoiT  and  his  pupils. 

It  is  absolutely  necessary  in  researches  on  the  exchange  of  material  to 
be  able  to  collect,  analyze,  and  quantitatively  estimate  the  excreta  of  the 
organism,  so  that  they  may  be  compared  with  tlie  quantity  and  composition 
of  the  nutritive  bodies  taken  up.  In  the  first  place,  one  must  know  what 
the  habitual  excreta  of  the  body  are  and  in  what  way  these  bodies  leave  the 
organism.  One  must  also  have  trustworthy  methods  for  the  quantitative 
estimation  of  the  same. 

The  organism  may,  under  physiological  conditions,  be  exposed  to  acci- 
dental or  periodic  losses  of  valuable  material — such  losses  as  only  occur  in 
certain  individuals,  or  in  the  same  individual  only  at  a  certain  period;  for 
instance,  the  secretion  of  milk,  the  production  of  eggs,  the  ejection  of 
semen  or  menstrual  blood.  It  is  therefore  apparent  that  these  losses  can 
be  the  subject  of  investigation  and  estimation  only  in  special  cases. 

The  regular  and  constant  excreta  of  the  organism  are  of  the  very 
greatest  importance  in  the  study  of  metabolism.  To  these  belong,  in  the 
first  place,  the  true  final  metabolic  products — caebox  dioxide,  urea  (uric 
acid,  hippuric  acid,  creatinin,  and  other  nrinary  constituents),  and  a  part 
of  the  WATER.  The  remainder  of  the  water,  the  mineral  bodies,  and  those 
secretions  or  tissue-constituents — mucus,  digestive  fluids,  sebum,  sweat, 
and  epidermis  formations — which  are  either  poured  into  the  intestinal 
tract,  or  secreted  from  the  surface  of  the  body,  or  broken  off  and  thereby 
lost  to  the  body,  also  belong  to  the  constant  excreta. 

The  remains  of  food,  sometimes  indigestible,  sometimes  digestible  but  not  acted 
upon,  contained  in  the  fteces,  which  vary  considerably  in  quantity  and  composition 
with  the  nature  of  the  food,  also  belong  to  the  excreta  of  the  organism.  Even  tliougii 
these  remains,  which  are  never  absorbed  and  therefore  are  never  constituents  of  the 
animal  fluids  or  tissues,  cannot  be  considered  as  excreta  of  the  body  in  a  strict  sense, 
still  their  quantitative  estimation  is  absolutely  necessary  in  certain  experiments  on  the 
exchange  of  material. 

The  determination  of  the  constant  loss  is  in  some  cases  accompanied  with  the 
greatest  difficulties.  The  loss  from  the  detached  epidermis,  from  the  secretion  of  the 
sebaceous  glands,  etc.,  cannot  be  determined  with  exactness  without  difiiculfy,  and 
therefore — as  they  do  not  occasion  any  appreciable  loss  because  of  their  small  quan- 
tity— they  need  not  be  considered  in  quantitative  experiments  on  metabolism.  This 
also  applies  to  the  constituents  of  the  mucus,  bile,  pancreatic  and  intestinal  juices,  etc., 
occurring  in  the  contents  of  the  intestine,  and  which,  leaving  the  body  with  the  faeces, 
cannot  be  separated  from  the  other  contents  of  the  intestine  and  therefore  cannot  be 
quantitatively  determined  separately.  The  uncertainly  \vhich,  because  of  the  inti- 
mated difficulties,  attaches  itself  to  the  results  of  the  experiments  is  very  small  as  com- 
pared to  the  variation  wliich  is  caused  by  different  individualities,  different  modes  of 
living,  different  foods,  etc.  No  general  but  only  approximate  values  can  therefore  be 
given  for  the  constant  excreta  of  the  human  body. 

The  following  figures  represent  the  quantity  of  excreta  for  24  hours  from 


548  METABOLISM. 

a  grown  man,  weighing  60-70  kilos,  on  a  mixed  diet.     The  numbers  are 
compiled  from  the  results  of  different  investigators. 

Grammes. 

Water 250(J-a500 

Salts  (with  the  urine) 20-30 

Cavbou  dioxide 750-900 

Urea 20-40 

Other  Ditrogenous  urinary  constituents 2-5 

Solids  in  the  excrements  30-50 

These  total  excreta  are  approximately  divided  among  the  various 
excretions  in  the  following  way — but  still  it  must  not  be  forgotten  that  this 
division  may  vary  to  a  great  extent  under  various  external  circumstances: 
by  KESPiRATiox  about  32,^,  by  the  eyaporatiox  from  the  skix  17^,  with 
the  URiXE  46-47.^,  and  with  the  excrements  5-9^.  The  elimination  by 
the  skin  and  lungs,  which  is  sometimes  differentiated  by  the  name  "  pers- 
piRATio  ixsexsibilis  "  from  the  visible  elimination  by  the  kidneys  and 
intestine,  is  on  an  average  about  50^  of  the  total  elimination.  This  propor- 
tion, quoted  only  relatively,  is  subject  to  considerable  variation,  because  of 
the  great  difference  in  the  loss  of  water  througli  the  skin  and  kidneys  under 
different  circumstances. 

The  nitrogenous  constituents  of  the  excretions  consist  chiefly  of  urea, 
or  uric  acid  in  certain  animals,  and  the  other  nitrogeneous  urinary  con- 
stitnents,  A  disproportionately  large  part  of  the  nitrogen  leaves  the  body 
with  the  urine,  and,  as  the  nitrogeneous  constitaents  of  this  excffetion  are 
final  products  of  the  metabolism  of  proteids  in  the  organism,  the  quantity 
of  proteids  catubolized  in  the  body  may  be  easily  calculated  by  multiplying 
the  quantity  of  nitrogen  in  the  urine  by  the  coefficient  6.25  (Jj'y-  =  6.25), 
if  we  admit  that  the  proteids  contain  in  round  number  165^  nitrogen. 

Still  another  question  is  whether  the  nitrogen  leaves  the  body  only  with 
the  urine  or  by  other  channels.  This  last  is  habitually  the  case.  The  dis- 
charges from  the  intestine  always  contain  some  nitrogen  which  has  a  twofold 
origin.  A  part  of  this  nitrogen  depends  upon  undigested  or  non-absorbed 
remnants  of  food,  and  another  part  on  the  non-absorbed  remains  of  diges- 
tive secretions — bile,  pancreatic  juice,  intestinal  mucus — and  of  epithelium- 
cells  of  the  mucous  membrane.  It  follows  that  a  part  of  the  nitrogen  of 
faeces  has  this  last-mentioned  origin  from  the  fact  that  discharges  from  the 
intestine  occur  also  in  complete  inanition. 

It  is  obvious  that  exact  results  which  answer  for  all  times  cannot  be 
given  for  that  part  of  the  nitrogen  which  has  its  origin  in  the  digestive 
canal  and  fluids.  It  may  not  only  vary  in  different  individuals,  but  also  in 
the  same  individual  after  more  or  less  active  secretion  and  absorption.  In 
the  attempts  made  to  determine  this  part  of  the  nitrogen  of  the  excrements 
it  has  been  found  that  in  man,  on  non-nitrogenous  or  nearly  nitrogen-free 
food,  it  amounts  in  round  numbers  to  somewhat  less  than  1  grm,  per  24 
hours  (RiEDER,  Rubner).     Even  with  such  food  the  absolute  quantity  of 


NITliOQEI^  ELIMINATION.  549 

nitrogen  eliminated  by  the  faeces  increases  with  the  quantity  of  food  because 
of  the  accelerated  digestion  (Tsunoi '),  and  is  greater  than  in  starvation. 
Muller'  found  in  his  observations  on  the  faster  Cetti  that  only  0.2  grni, 
nitrogen  was  derived  from  the  intestinal  canal. 

The  quantity  of  nitrogen  which  leaves  the  body  under  normal  circum- 
stances by  means  of  the  hair  and  nails,  with  the  scaling  oil  of  the  skin,  and 
with  the  perspiration  cannot  be  accurately  determined.  Only  in  profuse 
sweating  need  the  elimination  by  this  channel  be  taken  into  consideration. 

The  view  was  formerly  held  that  in  man  and  carnivora  an  elimination 
of  gaseous  nitrogen  took  place  through  the  skin  and  lungs,  and  because  of 
this,  on  comparing  the  nitrogen  of  the  food  with  that  of  the  nrine  and 
faeces,  a  nitrogen  deficit  occurred  in  the  visible  elimination. 

This  question  has  been  the  subject  of  much  discussion  and  of  numerous 
investigations.'  These  investigations  have  shown  that  the  above  assumption 
is  unfounded,  and  moreover  several  investigators,  es2)ecially  Pettexkofer 
and  VoiT,  and  Gruber,*  have  shown  by  experiments  on  man  and  animals 
that  with  tile  proper  quantity  find  quality  of  food  we  can  bring  the  body  into 
nitrogenous  equilibriian,  in  which  the  quantity  of  nitrogen  voided  with  the 
urine  and  fgeces  is  equal  or  nearly  equal  to  the  quantity  contained  in  the 
food.  Undoubtedly  we  must  admit  with  Yoit  that  a  deficit  of  nitrogen 
does  not  exist;  or  it  is  so  insignificant  that  in  experiments  ujion  metabolism 
it  need  not  be  considered.  Ordinarily,  in  investigations  on  the  catabolism 
of  proteids  in  the  body,  it  is  only  necessary  to  consider  the  nitrogen  of  the 
urine  and  fjeces,  but  it  must  be  remarked  that  the  nitrogen  of  the  urine  is 
a  measure  of  the  extent  of  the  catabolism  of  the  proteids  in  the  body, 
while  the  nitrogen  of  the  faeces  (after  deducting  about  1  grm.  on  mixed 
diet)  is  a  measure  of  th^  non-absorbed  part  of  the  nitrogen  of  the  food. 
The  nitrogen  of  the  food,  as  well  as  of  the  excreta,  is  generally  determined 
by  Kjeldarl's  method. 

In  the  oxidation  of  the  proteids  in  the  organism  their  suli^hur  is  oxidized 
into  sulphuric  acid,  and  on  this  depends  the  fact  that  the  elimination  of 
sulphuric  acid  by  the  urine,  which  in  man  is  only  to  a  small  extent  derived 
from  the  sulphates  of  the  food,  makes  nearly  equal  variations  as  the  elimi- 
nation of  nitrogen  by  the  nrine.  If  we  consider  the  amount  of  nitrogen 
and  sulphur  in  the  proteids  as  16^  and  1^  respectively,  then  the  proportion 

'  Rieder,  Zeitscbr.  f.  Biologic,  Bd.  20;  Rubner,  ibid.,  Bd.  15  ;  Tsuboi,  ibid.,  Bd.  35. 

»  Berlin,  klin.  Wocbenscbr.,  1887. 

*  See  Regnault  and  Roiset,  Annal.  d.  chim.  et  pbys.  (3),  Tome  26,  aud  Aniial.  d. 
Chem.  u.  Pbarm.,  Bd.  73;  Seegen  and  Nowak,  Wien.  Sitzungsber..  Bd.  71,  aud  Pfluger'a 
Aicb.,  Bd.  25;  Pettenkofer  aud  Voit,  Zeitscbr.  f.  Biologic,  Bd.  16;  Leo,  Pfliiger's 
Aicb.,  Bd.  26. 

■•  PeUcnkofer  and  "Voit  in  Hermanu's  Haudbucb,  Bd.  6,  Tbl.  1 ;  Gruber,  Zeitscbr.  f. 
Biologic,  Bdd.  16  aud  19. 


550  METABOLISM. 

between  the  nitrogen  of  the  proteids  and  the  salpharic  acid,  H^SO^,  pro- 
duced by  their  combustion  is  in  the  ratio  5.2  :  1,  or  about  the  same  as  in 
the  urine  (see  page  4G9).  The  determination  of  the  quantity  of  sulphuric 
acid  eliminated  with  the  urine  gives  us  an  important  means  of  coatrolling 
the  extent  of  the  transformation  of  proteids,  and  such  a  control  is  es^Jecially 
important  in  cases  in  which  we  wish  to  study  the  action  of  certain  nitrog- 
enous non-albuminous  bodies  on  the  metabolism  of  proteids.  A  determi- 
nation of  the  nitrogen  alone  is  not  sufficient  in  such  cases. 

The  pseudonucleins,  as  well  as  the  true  nucleins,  may  be  absorbed  from 
the  intestinal  tract  and  then  assimilated  (Gumlich,  Saxdmeyee,  Marcuse, 
EoHMANN,  and  Steinitz  ').  On  the  other  hand,  the  phosphorized  protein 
substances,  lecithins  and  protagons,  are  also  decomposed  within  the  body, 
and  their  phosphorus  is  chiefly  eliminated  as  phosphoric  acid  and  also  in 
part  as  organically  combined  phosphorus  (see  Chapter  XV,  page  4(52).  For 
these  reasons  the  phosphorus  is  of  great  importance  in  certain  inv^estigations 
on  metabolism.' 

If  it  is  found,  on  comparing  the  nitrogen  of  the  food  with  that  of  the 
urine  and  faeces,  that  there  is  an  excess  of  the  first,  this  means  that  the 
body  has  increased  its  stock  of  nitrogenous  substances— proteids.  If,  on 
the  contrary,  the  urine  and  fseces  contain  more  nitrogen  than  the  food  taken 
at  the  same  time,  this  denotes  that  the  body  is  giving  up  part  of  its 
nitrogen — that  is,  a  part  of  its  own  proteids  has  been  decomposed>.  We 
can,  from  the  quantity  of  nitrogen,  as  above  stated,  calculate  the  corre- 
sponding quantity  of  proteids  by  multiplying  by  6.25.  Usually,  according 
to  Voit's  proposition,  the  nitrogen  of  the  urine  is  not  calculated  as  decom- 
posed proteids,  but  as  decomposed  muscle-substance  or  flesh.  Lean  meat 
contains  on  an  average  about  3.4^  nitrogen;  hence  each  gramme  of  nitrogen 
of  the  urine  corresponds  in  round  numbers  to  about  30  grms.  flesh.  The 
assumption  that  lean  meat  contains  3.4,^  nitrogen  is  arbitrary,  as  specially 
shown  by  Pfluger,  and  the  relationship  of  N  :  C  in  the  proteids  of  dried 
meat,  which  is  of  great  importance  in  certain  experiments  on  metabolism, 
is  given  differently  by  various  experimenters,  namely,  1  :  3.22 — 1  :  3.68, 
Argutinsky  '  found  in  ox-flesh,  after  complete  removal  of  fat  and  subtrac- 
tion of  glycogen,  that  the  relationship  was  1  :  3.24. 

A  disproportionately  large  part  of  the  carbon  leaves  the  body  as  carbon 
dioxide,  which  escapes  chiefly  through  the  lungs  and  skin.  The  remainder 
of  the  carbon  is  eliminated  in  the  form  of  organic  combinations  by  the  urine 
and  faeces,  in  which  the  quantity  of  carbon  can  be  determined  by  elementary 

'  Steinitz,  Pflligei's  Arch.,  Bd.  72,  which  contains  the  work  of  tlie  other  authors 
cited. 

'  In  regard  to  the  methods  in  this  connection  .see  Steinitz,  1.  c ;  Oertel,  Zeitschr.  f. 
physiol.  Chem.,  Bd.  26. 

2  Pfluger,  Pfluger's  Arch.,  Bd.  51,  S.  229  ;  Arguliusky,  ibid.,  Bd.  55. 


CALCULATION  OF  TUB  EXTENT  OF  METABOLISM.  601 

analysis.  For  most  pnrposes  it  is  sufticieut  to  calculate  the  quantity  of 
carbon  in  the  urine  from  the  quantity  of  nitrogen  according  to  the  relation- 
ship N  :  C  =  1  :  0.67  (Pfluger).  The  quantity  of  gaseous  carbon  dioxide 
eliminated  may  be  determined  by  means  of  Pettexkofer's  respiration 
apparatus,  or  by  other  methods  as  described  in  the  preceding  chapter.  By 
multiplying  the  quantity  of  carbon  dioxide  found  by  0.273  we  obtain  the 
quantity  of  carbon  eliminated  as  CO,.  If  we  compare  the  total  quantity  of 
carbon  eliminated  in  -various  ways  with  the  carbon  contained  in  the  food 
we  obtain  some  idea  as  to  the  transformation  of  the  carbon  compounds.  If 
the  quantity  of  carbon  in  tlie  food  is  greater  than  in  the  excreta,  then  the 
excess  is  deposited;  while  if  the  reverse  be  the  case  it  shows  a  corresponding 
loss  of  body  substance. 

The  nature  of  the  substances  here  deposited  or  lost,  whether  they  con- 
sist of  proteids,  fats,  or  carbohydrates,  is  learned  from  the  total  quantity  of 
nitrogen  of  the  excretions.  The  corresponding  quantity  of  proteids  may 
be  calculated  from  the  quantity  of  nitrogen,  and,  as  the  average  quantity 
of  carbon  in  the  jiroteids  is  known,  the  quantity  of  carbon  which  corre- 
sponds to  the  decomposed  proteids  may  be  easily  ascertained.  If  the 
quantity  of  carbon  thus  found  is  smaller  than  the  quantity  of  the  total 
carbon  in  the  excreta,  it  is  then  obvious  that  some  other  nitrogen-free  sub- 
stance has  been  consumed  besides  the  proteids.  If  the  quantity  of  carbon 
in  the  proteids  is  considered  in  round  numbers  as  53$^,'  then  the  relation 
between  carbon  (53)  and  nitrogen  (IG)  is  as  3.3  :  1.  If  we  multiply  the 
total  quantity  of  nitrogen  eliminated  by  3.3,  the  excess  of  carbon  in  the 
eliminations  over  the  product  found  represents  the  carbon  of  the  decom- 
posed non-nitrogenous  compounds.  For  instance,  in  the  case  of  a  person 
experimented  upon,  10  grms.  nitrogen  and  200  grms.  carbon  were  elimi- 
nated in  the  course  of  24:  hours;  then  these  G2.5  grms.  proteid  correspond 
to  33  grms.  carbon,  and  the  dilTerence,  200  —  (3.3  X  10)  =  1G7,  represents 
the  quantity  of  carbon  in  the  decomposed  non-nitrogenous  compounds.  If 
we  start  from  the  simplest  case,  starvation,  where  the  body  lives  at  the 
expense  of  its  own  substance,  then,  since  the  quantity  of  carbohydrates  as 
compared  with  the  fats  of  the  body  is  extremely  small,  in  such  cases  in  order 
to  avoid  mistakes  the  assumption  must  be  made  that  the  person  experi- 
mented upon  has  used  only  fat  and  proteids.  As  animal  fat  contains  on  an 
average  7G.5^  carbon,  the  quantity  of  transformed  fat  may  be  calculated  by 

multiplying  the  carbon  bv  ^t-tt.  =  1-3.     In  the  case  of  the  above  example 

the  person  experimented  npon  would  have  used  02.5  grms.  proteids  and 
1G7  X  1.3  —  217  grms.  fat  of  his  own  body  in  the  course  of  the  24  hours. 
Starting  from  the  nitrogen  balance,  we  can  calculate  in  the  same  way 


'  This  figure  is  perhaps  a  little  loo  high. 


552  METABOLISM. 

whether  an  excess  of  carbon  in  the  food  as  compared  with  the  qaantity  of 
carbon  in  the  excreta  is  retained  by  the  body  as  proteids  or  fat  or  as  both. 
On  the  other  hand,  with  an  excess  of  carbon  in  the  excreta  we  can  calculate 
iiow  mnch  of  the  loss  of  the  substance  of  the  body  is  due  to  a  consumption 
of  the  proteids  or  of  fat  or  of  both. 

The  quantity  of  water  and  mineral  bodies  voided  with  the  urine  and 
faeces  can  easily  be  determined.  The  quantity  of  water  eliminated  by  the 
skin  and  lungs  may  be  directly  determined  by  means  of  Pettenkofer's 
ajjparatus.  The  quantity  of  oxygen  taken  up  is  calculated  as  the  difference 
between  the  weight  of  the  individual  before  the  experiment  plus  all  the 
directly  determined  substances  taken  in,  and  the  final  weight  of  the  indi- 
vidual plus  all  his  excreta. 

The  oxygen  may,  according  to  the  methods  given  in  the  preceding 
chapter,  be  directly  determined,  and  such  a  determination  with  the  simul- 
taneous estimation  of  the  carbon  dioxide  eliminated  is  of  great  importance 
in  the  study  of  metabolism. 

On  comparing  the  inspired  and  the  expired  air  we  learn,  on  measuring 
them  when  dry  and  at  the  same  temperature  and  pressure,  that  the  volume 
of  the  expired  air  is  less  than  that  of  the  inspired  air.  This  depends  upon 
the  fact  that  not  all  of  the  oxygen  appears  again  in  the  expired  air  as 
carbon  dioxide,  because  it  is  not  only  used  in  the  oxidation  of  carbon,  but 
also  in  part  in  the  formation  of  water,  sulphuric  acid,  and  oth^  bodies. 
The  volume  of  expired  carbon  dioxide  is  regularly  less  than  the  volume  of 

CO 

the  inspired  oxygen,  and  the  relation  -pr,  which  is  called  the  resfiratory 

quotient^  is  generally  less  than  1. 

The  magnitude  of  the  respiratory  quotient  is  dependent  upon  the  kind 
of  substances  destroyed  in  the  body.  In  the  combustion  of  pure  carbon 
one  volume  of  oxygen  yields  one  volume  of  carbon  dioxide,  and  the  quotient 
is  therefore  equal  to  1.  The  same  is  true  in  the  burning  of  carbohydrates, 
and  in  the  exclusive  decomposition  of  carbohydrates  in  the  animal  body  the 
respiratory  quotient  must  be  approximately  1.  In  exclusive  metabolism  of 
proteids  it  is  0.73,  and  with  the  decomposition  of  fat  it  is  0.7.  In  starva- 
tion, as  the  animal  draws  on  its  own  flesh  and  fat,  the  respiratory  quotient 
must  be  a  close  approach  to  the  latter  figure.  The  respiratory  quotient 
therefore  gives  important  data  on  the  quality  of  the  material  decom- 
posed in  the  body,  naturally  with  the  supposition  that  the  elimination 
of  carbon  dioxide,  independent  of  the  formation  of  carbon  dioxide,  is  not 
influenced  by  special  conditions,  such  as  alternation  of  the  respiratory 
mechanism. 

It  is  also  possible  in  systematized  experimentation  to  carry  on  the 
metabolism  experiments  so  that  the  decomposable  material  of  the  body,  as 
shown  by  the  respiratory  quotient,  remains  qualitatively  the  same,  at  least 


EXCHANGE  OF  GAS  AS  A   MEASURE  OF  METABOLISM.         553 

for  a  short  time.  In  such  exjieriments  it  lias  been  shown,  especially  by 
ZuNTZ  and  his  pnpils,'  that  the  extent  of  oxygen  consami^tion  may  be  taken 
as  a  measure  for  the  action  of  dilTerent  influences  on  the  extent  of  meta- 
bolism. This  possibility  is  based  on  the  fact  proved  by  Pfluger  and  his 
pupils,  and  by  Voit,"  that  the  consumption  of  oxygen  within  wide  limits  is 
independent  of  the  supply  of  oxygen,  and  is  exclusively  dependent  upon 
the  oxygen  demand  of  the  tissues.  For  certain  reasons  the  consumption  of 
oxygen  gives  indeed  a  better  conclusion  than  the  elimination  of  carbon 
dioxide  as  to  the  extent  of  exchange  of  material  and  energy;  but  as  the 
same  quantity  of  oxygen  (100  grms.)  consumes  different  quantities  of  fat, 
carbohydrates,  and  proteids  in  the  body — namely,  35,  84.4,  and  74.4  grms. 
respectively — the  respiratory  quotient  must  also  be  determined,  in  order  to 
ascertain  the  nature  of  the  substance  burnt  in  the  body,  simultaneously  with 
the  determination  of  the  carbon  dioxide. 

As  the  different  foods  require  different  amounts  of  oxygen  in  tlie  combustion  of 
each  gram  of  substance  and  yield  different  amounts  of  COj .  each  gram  of  oxygen 
taken  up  and  each  gram  of  carbon  in  the  expired  air  as  carbon  dioxide  must  correspond 
to  different  heat-values      This  follows  from  the  following  table: 

Calories  Calories 

pergrni.C  Rflalive       perRrm.        Relative 
in  the  CO3  of        Value.       Cotisunied         Value, 
tlie  Expired  Air.  Oxygen. 

In  the  combustion  of  cane-sugar 9.5  100  i5.56  118.6 

"    "  "  "meat 10.2  107  3.00  100.0 

"    •'  "  "fat 12.3  129  3.27  109.0 

The  figures  for  the  oxygen  differ,  as  above  seen,  less  than  those  for  the  carbon,  and 
this  is  the  reason  wh}^  as  above  stated,  the  oxygen  consumption  gives  a  much  more 
correct  conchisiou  as  to  the  exchange  of  force  than  the  elimination  of  carbon  dioxide.* 

Kaufmann  *  encloses  the  individual  to  be  experimented  upon  in  a  capa- 
cious tin  box,  which  serves  both  as  a  respiration-chamber  and  a  calorimeter, 
and  -which  permits  of  the  estimation  of  the  nitrogen  of  the  urine  and  the  car- 
bon dioxide  expired,  as  -well  as  the  inspired  oxygen  and  the  quantity  of  heat 
produced.  If  we  start  from  the  theoretically  calculated  formula?  for  the 
various  possible  transformations  of  the  proteids,  fats,  and  carbohydrates  in 
the  body,  it  is  clear  that  other  values  must  be  obtained  for  the  heat,  carbon 
dioxide,  oxygen,  and  nitrogen  of  the  urine,  when  we,  for  example,  admit  of 
a  complete  combustion  of  proteids  to  urea,  carbon  dioxide,  and  water,  or 
■when  we  admit  of  a  partial  splitting  off  of  fat.  Another  relationship 
between  heat,  carbon  dioxide,  and  oxygen  is  also  to  be  expected  when  the 
fat  is  completely  burnt  or  when  it  is  decomposed  into  sugar,  carbon  dioxide, 
and  water.  In  this  way,  by  a  comparison  of  the  values  found  in  special 
cases  with  the  figures  calculated  for  the  various  transformations,  Kaufmaxn" 

'  See  foot-note  4,  page  544. 

'PflUger.  Ptlliger's  Arch.,  Bdd.   G,   10,  u.   14;  Finkler,  ibid.,  iid.   10;  Fiukler  and 
Oertmaun,  ibid.,  Bd.  14  ;  Voit.  Zeitschr.  f.  Biologie,  Bdd.  11  and  14. 
'  See  Ad.  Magnus-Levy,  PflUger's  Arch.,  Bd.  55,  S.  7. 
^  Arch.  d.  Physiologic  f5),  Tome  8. 


554  METABOLISM. 

attempts  to  explain  the  various  decomposition  processes  in  the  body  under 
different  nutritive  conditions. 

I.  Potential  Energy  and  the  Relative  Nutritive  Value 
of  Various  Organic  Foodstviflfs. 

With  the  organic  foods  the  organism  receives  a  supply  of  potential 
energy  which  is  converted  into  living  force  in  the  body.  This  potential 
energy  of  the  various  foods  may  be  represented  by  the  amount  of  heat 
which  is  set  free  in  their  combustion.  This  quantity  of  heat  is  expressed 
as  calories,  and  a  small  calorie  is  the  quantity  of  heat  necessary  to  warm 
1  grm.  water  from  0°  to  1°  C.  A  large  calorie  is  the  quantity  of  heat 
necessary  to  warm  1  kilo  water  1°  C.  Here  and  in  the  following  pages  large 
calories  are  to  be  understood.  We  have  numerous  investigations  by  differ- 
ent experimenters,  such  as  Fraitkland,  Danilewski,  Rubber,  Berthe- 
LOT,  Stohmank,  and  others,  on  the  calorific  value  of  different  foods.  The 
following  results,  which  represent  the  calorific  value  of  a  few  nutritive 
bodies  on  complete  combustion  outside  of  the  body  to  the  highest  oxidation 
products,  are  taken  from  Stohmann's  '  latest  work. 

Calories. 

Casein 5-86 

Ovalbumin 5.74 

Conglutin 5.48 

Proteid  (average) 5.7L-^ 

Animal  tissue-fat 9. 50 

Butter-fat , 9.23 

Cane-sugar 3.96 

Lactose 3.95 

Dextrose 3.74 

Starcli 4.19 

Pat  and  carbohydrates  are  completely  burnt  in  the  body,  and  we  can 
therefore  consider  their  combustion  equivalent  as  a  measure  of  the  living 
force  developed  by  them  within  the  organism.  We  generally  designate  9.3 
and  4.1  calories  for  each  grm.  of  substance  as  the  average  for  the  physio- 
logical calorific  value  of  fats  and  carbohydrates  respectively. 

The  proteids  act  differently  from  the  fats  and  carbohydrates.  They  are 
only  incompletely  burnt,  and  they  yield  certain  decomposition  products, 
which,  leaving  the  body  with  the  excreta,  still  represent  a  certain  quantity 
of  potential  energy  which  is  lost  to  the  body.  The  heat  of  combustion  of 
the  proteids  is  smaller  within  the  organism  than  outside  of  it,  and  they 
must  therefore  be  specially  determined.  For  this  purpose  Eubner'  fed  a 
dog  on  washed  meat,  and  he  subtracted  from  the  heat  of  combustion  of  the 
food  the  heat  of  combustion  of  the  urine  and  faeces,  which  corresponded  to 

'  See  Rubiier,  Zeit'sclir.  f.  Biologic,  Bd.  21,  wliicli  also  cites  the  works  of  Frankland 
and  Daiiilevvski;  see  also  Bertbelot,  Compt.  leud.,  Tomes  103,  104,  and  110;  Stohraann, 
Zeitscbr.  f.  Biologic,  Bd.  31. 

»  Zeitscbr.  f .  Biologie,  Bd.  21. 


CALORIFIC    VALUES  OF  FOODSTUFFS.  5&i) 

the  food  taken  pins  tlie  quantity  of  lieat  necessary  for  the  swelling  up  of 
the  iiroteitls  and  the  solution  of  the  urea.  Kuijxkr  has  also  tried  to  deter- 
mine the  heat  of  combustion  of  the  proteids  (muscle-proteids)  decomposed 
in  the  body  of  rabbits  in  starvation.  According  to  these  investigations,  the 
physiological  heat  of  combustion  in  calories  for  each  gramme  of  substance 
is  as  follows : 

1  prm.  of  the  Dry  Substance.  Calories. 

Protuids  from  meat 4.4 

Musclo 4.0 

Proteids  iu  starvjitiou 3.8 

Fat  (iiverage  for  various  fats)  9.3 

Carbohydrates  (calculated  average) 4.1 

The  physiological  combustion  value  of  the  various  foods  belonging  to 
the  same  group  is  not  quite  the  same.  It  is,  for  instance,  3.97  calories  for 
a  vegetable  proteid,  conglntin,  and  4.42  calories  for  an  animal  proteid 
body,  syntonin.  According  to  Rubner  we  may  consider  the  normal  heat 
value  per  1  grm.  of  animal  proteid  as  4.23  calories,  and  of  vegetable  proteid 
as  3.96  calories.  When  a  person  on  a  mixed  diet  takes  about  GO^  of  the 
proteids  from  animal  foods  and  about  40^  from  vegetable  foods,  we  may 
consider  the  value  of  1  grm.  of  the  proteid  of  the  food  as  about  4.1  calories. 
The  physiological  value  of  each  of  the  three  chief  groups  of  organic  foods, 
by  their  decomposition  in  the  body,  is  in  round  numbers  as  follows: 

Calories. 

1  grm.  proteid 4.1 

1     "      fat 9.3 

1     "      carbohydrate 4.1 

As  will  be  shown,  the  fats  and  carbohydrates  may  decrease  the  meta- 
bolism of  proteids  in  the  body,  while,  on  the  other  hand,  the  quantity  of 
proteids  in  the  body  or  in  the  food  acts  on  the  metabolism  of  fat  in  the 
body.  In  physiological  combustion  the  various  foods  may  replace  one 
another  to  a  certain  extent,  and  it  is  therefore  important  to  know  the 
ratio  of  replacement.  The  investigations  made  by  Rubner  have  taught 
that  this,  if  it  relates  to  the  force  and  heat  production  in  the  animal 
body,  is  a  proportion  that  corresponds  with  the  figures  of  the  heat  value 
of  the  same.  This  is  apparent  from  the  following  table.  In  this  we 
find  the  weight  of  the  various  foods  equal  to  100  grms.  fat,  a  part  deter- 
mined from  experiments  on  animals  and  a  part  calculated  from  lignres  of 
the  heat  values. 

Table  I. 
100  grms.  fat  are  equal  to  or  isodynamic  with  . 

From  E.xperiments  From  the  Difference, 

on  Animals.  Heat  Value.  percent. 

Syntonin..    225  213  +5.6 

Muscle-flesh  (dried) 243  235  +4.3 

Starch 232  229  +1.3 

Cane-sugar 234  235  -  0 

Grape-sugar...   256  255  —0 


656  METABOLISM. 

From  the  given  isodynamic  value  of  the  various  foods  it  follows  that 
these  substances  replace  one  another  in  the  body  almost  in  exact  ratio  to 
the  potential  energy  contained  in  them.  Thus  in  round  numbers  227 
grms.  proteid  and  carbohydrate  are  equal  to  or  isodynamic  with  100  grms. 
fat  in  regard  to  source  of  energy,  because  each  yields  930  calories  on  com- 
bustion in  the  body. 

By  means  of  recent  very  imjDortant  calorimetric  investigations  Eubner  ' 
has  shown  that  the  heat  produced  in  an  animal  in  several  series  of  ex- 
periments extending  over  45  days  corresponded  to  within  0.47^  of  the 
physiological  heat  of  combustion  calculated  from  the  decomposed  body  and 
foods. 

According  lo  Chatjveau  the  carbohydrates  aud  the  fat,  iu  working  animals,  do  not 
replace  one  anotlier  according  to  the  isocaloric  values;  but,  as  shown  by  Zuntz,' the 
experiments  on  this  subject  are  not  sufficiently  couckisive. 

This  isodynamic  law  is  of  fundamental  valne  in  the  study  of  metabolism 
and  nutrition.  By  this  law  it  is  possible  to  consider  the  processes  of  meta- 
bolism as  more  uniform.  The  quantity  of  energy  in  the  foods  may  be  used 
as  a  measure  for  the  total  consumption  of  energy,  and  the  knowledge  of  the 
quantity  of  energy  in  the  foods  must  also  be  the  basis  for  the  calculation  of 
dietaries  for  human  beings  under  various  conditions. 

II.  Metabolism  in  Starvation.        ~^ 

In  starvation  the  decomposition  in  the  body  continues  uninterruptedly, 
though  with  decreased  intensity;  but,  as  it  takes  place  at  the  expense  of 
the  substance  of  the  body,  it  can  only  continue  for  a  limited  time.  When 
an  animal  has  lost  a  certain  fraction  of  the  mass  of  the  body  death  is  the 
result.  This  fraction  varies  with  the  condition  of  the  body  at  the  beginning 
of  the  starvation  period.  Fat  animals  succumb  when  the  weight  of  the 
body  has  sunk  to  one  half  of  tiie  original  weight.  Otherwise,  according  to 
Ohossat,'  animals  die  as  a  rule  when  the  weight  of  the  body  has  sunk  to 
two  fifths  of  the  original  weight.  The  period  when  death  occurs  from 
starvation  not  only  varies  with  the  varied  nutritive  condifcion  at  the  begin- 
ning of  starvation,  but  also  with  the  more  or  less  active  exchange  of 
material.  This  is  more  active  in  small  and  young  animals  than  in  large 
and  older  ones,  but  different  classes  of  animals  sliow  an  unequal  activity. 
Children  succumb  in  starvation  in  3-5  days  after  having  lost  one  fourth  of 
their  bodily  mass.  Grown  persons,  as  observed  on  Succi,*  may  starve  for 
20  days  without  lasting  injury;  and  we  have  reports  of  cases  of  starvation 

1  Ztitschr.  f.  Biologic,  Bd.  30. 

'  Chauveau,  Compt.  rend..  Tome  125  ;  Zunlz,  Dn  Bois-Reymond's  Arch.,  1898. 

"  Cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6.  Thl.  1,  S.  100. 

*  See  Luciani,  Das  Hungern.     Hamburg  u.  Leipzig,  1890. 


METABOLISM  IN  STARVATION.  557 

extending  over  a  period  of  even  more  than  50  days.  Dogs  can  live  without 
food  from  4-S  weeks,  birds  5-20  days,  snakes  more  than  half  a  year,  and 
frogs  more  than  a  year. 

In  starvation-  the  zveight  of  the  body  decreases.  The  loss  of  weight  is 
greatest  in  tlie  first  few  days,  and  then  decreases  rather  uniformly.  In 
small  animals  the  absolute  loss  of  weight  per  day  is  naturally  less  than 
in  larger  animals.  The  relative  loss  of  weight — that  is,  the  loss  of  weight 
of  the  unit  of  the  weight  of  the  body,  namely,  1  kilo — is,  on  tlie  contrary, 
greater  in  small  animals  than  in  larger  ones.  The  reason  for  this  is  that 
the  smaller  animals  have  a  greater  surface  of  body  in  proportion  to  their 
mass  than  larger  animals,  and  the  greater  loss  of  heat  cansed  thereby  must 
be  replaced  by  a  more  active  consumption  of  material. 

It  follows  from  the  decrease  in  the  weight  of  the  body  that  the  absolute 
extent  of  metabolism  must  diminish  in  starvation.  If,  on  the  contrary,  we 
refer  the  extent  of  the  metabolism  to  the  unit  of  the  weight  of  the  body, 
namely,  1  kilo,  we  find  that  this  quantity  remains  nearly  unchanged  during 
starvation.  The  investigations  of  Zuxtz,  Lehmann,  and  others  '  on  Cetti 
showed  on  the  3d  to  6th  day  of  starvation  an  average  consumption  of  4.05 
c.c.  oxygen  per  kilo  in  one  minute,  and  on  the  9th  to  11th  day  an  average  of 
4.73  c.c.  The  calories,  as  a  measure  of  the  metabolism,  fell  on  the  1st  to  5th 
day  of  starvation  from  1850  to  IGOO  calories,  or  from  32.4  to  30  per  kilo,  and 
he  remained  nearly  unchanged,  if  we  refer  to  tlie  unit  of  bodily  weight.' 

As  the  metabolism  in  starvation  takes  jilace  at  the  expense  of  the  con- 
stituents of  the  body,  it  must  take  place  in  essentially  the  same  way  in  both 
carnivora  and  herbivora.  As  the  food  of  the  herbivora  is  ordinarily  richer 
in  carbohydrates  and  non-nitrogenous  nutritive  bodies  than  that  of  the 
carnivora,  so  in  starvation  the  body  of  the  herbivora  becomes  relatively 
richer  in  proteids.  On  this  account  the  elimination  of  nitrogen  is  increased 
in  herbivora  in  the  first  part  of  the  period  of  starvation.  In  carnivora  the 
elimination  of  nitrogen  decreases,  as  a  rule,  immediately  at  the  beginnirg 
of  the  starvation  period,  and  in  the  later  stages  only  small  quantities  cf 
nitrogen  are  voided  by  herbivora  as  well  as  by  carnivora. 

This  increase  may  be  explained  (Prausnitz,  Tigekstedt  '■')  as  follows  :  At  the  com- 
niencement  of  starvation  the  proteid  metabolism  is  reduced  by  the  glycogen  still 
present  in  the  body.  After  the  consumption  of  the  glycogen,  which  takes  place  in  great 
part  during  the  first  days  of  starvation,  the  destruction  of  proteids  increases  as  the  gly- 
cogen action  decreases,  and  then  decreases  again  when  the  body  has  become  poorer  in 
available  proteids. 

The  extent  of  the  metalolism  of  proteids,  or  the  elimination  of  nitrogen 
by  the  urine,  which  is  a  measure  of  the  same,  does  not  show  in  carnivora 
any  uniform  decrease  during  the  entire  period  of  starvation.     During  the 

>  Berlin,  klin.  Wocheuschr.,  1887. 

*  See  also  Tigerstedt  and  collaborators  in  Skand.  Arch.  f.  Physiol.,  Bd.  7. 

*  Prausnitz,  Zeitschr.  f.  Biologic,  Bd.  29  ;  Tigerstedt  and  collaborators,  1.  c. 


658  METABOLISM. 

first  few  days  the  elimination  of  nitrogen  is  greatest,  and  the  quantity  of 
the  same  depends  essentially  upon  the  amount  of  proteids  in  the  organism 
and  the  nature  of  the  food  previously  taken.  The  richer  the  body  is  in 
proteids  from  the  food  previously  taken  the  greater  is  the  metabolism  of 
proteids,  or,  in  other  words,  the  elimination  of  nitrogen  is  greater  during 
the  first  days  of  starvation.  The  rapidity  with  which  the  elimination  of 
nitrogen  decreases  in  the  first  days  depends  also,  according  to  Voit,  upon 
the  proteid  condition  of  the  body.  It  decreases  more  quickly — that  is,  the 
curve  of  the  decrease  is  more  sudden — the  first  days  of  starvation,  as  a  rule, 
the  richer  in  proteids  the  food  was  which  was  taken  before  starvation. 
This  condition  is  apparent  from  the  following  table  of  data  of  three 
different  starvation  experiments  made  by  Voit  '  on  the  same  dog.  This 
dog  received  2500  grms.  meat  daily  before  the  first  series  of  experiments, 
1500  grms.  meat  daily  before  the  second  series,  and  a  mixed  diet  relatively 
poor  in  nitrogen  before  the  third  series. 

Table  II. 

Day  of  Starvation.  ^''^Tr!  1°^  ^'^^  ^'™  Sen  n!°  '^'^^°*^'*°slr^lll!"'" 

1st 60.1  26.5  13.8 

2d 24.9  18.6  11.5 

3d 19.1  15.7  10.3 

4th 17.3  14.9  12.2 

5th 123  14.8  _12.1 

6th 13.3  12.8  12.6 

7th 12.5  12.9  11.3 

8th 10.1  12.1  10.7 

Other  conditions,  such  as  varying  quantities  of  fat  in  the  body,  have  an 
influence  on  the  rapidity  with  which  the  nitrogen  is  eliminated  during  the 
first  days  of  starvation.  After  the  first  few  days  the  elimination  of 
nitrogen,  as  is  seen  in  the  above  table,  is  more  uniform,  and  as  the  starva- 
tion proceeds  it  decreases  as  a  rule  very  slowly  and  uniformly.  Cases  also 
occur  in  which  the  elimination  of  nitrogen  becomes  constant  in  these  stages, 
and  towards  the  end,  indeed,  the  elimination  of  nitrogen  increases.  This 
so-called  ante-mortem  increase  always  occurs  as  soon  as  the  adipose  tissue  in 
the  body  has  sunk  to  a  certain  point,  and  it  also  depends  on  the  fact  that 
as  soon  as  the  fat  is  consumed  a  corresponding  increase  in  the  decomposition 
of  proteids  is  necessary  for  the  generation  of  heat  as  well  as  of  other  forms 
of  living  force. 

Besides  tlie  proteids,  the  fat  occurring  in  the  body  is  also  decomposed 
in  starvation.  Since  fat  has  a  diminishing  influence  on  the  destruction  of 
proteids  (see  farther  on),  the  elimination  of  nitrogen  in  starvation  is  less  in 
fat  than  in  lean  individuals.  For  instance,  only  9  grms.  of  urea  were 
voided  in  24  hours  during  the  later  stages  of  starvation  by  a  well-nourished 
and  fat  person  suffering  from  disease  of  the  brain,  while  I.  Munk  found 

'  Physiol,  des  Stoffwechsels,  etc.,  in  Hermann's  Hiindbuch,  Bd.  6,  Thl.  1,  S.  89. 


METABOLISM  IN  STARVATION.  559 

that  20-29  grms.  urea  were  voided  daily  by  Cetti,'  who  had  been  poorly 
nourished. 

Like  the  destruction  of  proteids  during  starvation,  the  decomposition 
of  fat  proceeds-  uninterruptedly,  but  does  not  show  so  great  and  rapid  a 
decrease  in  the  first  days  of  starvation  as  the  proteids.  Pettenkofer  and 
VoiT  found,  for  instance,  in  a  starving  dog  the  following  losses  of  proteids 
and  fat  from  the  body  on  different  days  of  starvation: 

Table  III. 

_.  Loss  of  Loss  of 

^^y*  Flesh.       Calories.*  Fat.  Calories. 

2(1 341  297.3  86  799.8 

5lh 167  145.6  103  907.9 

8tb 138  120.1  99  920.7 

The  consumption  of  fat  on  the  second  day,  when  the  decomposition  of 
proteids  was  considerable,  was  in  fact  less  than  in  the  following  days.  The 
reason  for  this  was  that  the  animal  had  previously  been  fed  with  abundant 
quantities  of  meat  (2500  grms.).  If  the  exchange  is  expressed  as  calories 
we  find  for  the  fifth  and  eighth  days  of  starvation  that  13. 2^^  and  11. 5,^^ 
respectively  of  the  total  calories  were  covered  by  the  decomposition  of  pro- 
teids, and  8G.8^  and  88. o,'^  by  the  decomposition  of  fat.  Other  observations 
on  animals  as  well  as  man  have  led  to  a  similar  result,  and  we  can  assume 
that  in  starvation  ordinarily  the  greatest  part  of  the  expenditure  is  replaced 
by  the  decomposition  of  fat,  and  only  a  small  part  by  the  decomposition  of 
proteids. 

The  investigations  on  the  exchange  of  gas  in  starvation  have  shown,  as 
previously  mentioned,  that  the  absolute  extent  of  the  same  is  diminished, 
but  that  when  the  consumption  of  oxygen  and  elimination  of  carbon 
dioxide  is  calculated  on  the  unit  of  weight  of  the  body,  1  kilo,  this  quantity 
quickly  sinks  to  a  minimum  and  then  remains  unchanged,  or,  on  the  con- 
tinuation of  the  starvation,  may  actually  rise.  It  is  a  generally  known  fact 
that  the  body  temperature  of  starving  animals  remains  nearly  constant, 
without  showing  any  appreciable  decrease,  during  the  greater  part  of  the 
starvation  period.  The  temperature  of  the  animal  first  sinks  a  few  days 
before  death,  and  death  occurs  at  about  33-30°  C. 

From  what  has  been  said  about  the  respiratory  quotient  it  follows  that  in 
starvation  it  is  about  the  same  as  with  fat  and  meat  exclusively  as  food,  i.e., 
approximately  0.7.  This  is  often  the  case,  but  it  may  occasionally  be  lower, 
0.G5-0.50,  as  observed  in  the  cases  of  Cetti  and  Succi.     As  explanation 

'L.  c. 

'  The  calorics  of  the  decomposed  proteids  were  calculated  by  the  author,  assuming 
that  the  flesh  contains  ZA%  nitrogen  as  proteids. 


560  METABOLISM. 

for  this  unexpected  behavior  we  admit  of  a  storage  of  incompletely  oxidized 
substances  in  the  body  during  starvation. 

Water  passes  uninterruptedly  from  the  body  in  starvation  even  when 
none  is  taken.  If  the  quantity  of  water  in  the  tissues  rich  in  proteids  is 
considered  as  70-80^,  and  the  quantity  of  proteids  in  the  same  20^,  then 
for  each  gramme  of  destroyed  proteids  about  4  grammes  of  water  is  set  free. 

The  loss  of  water  calculated  ou  the  percentage  of  the  total  organism  must  naturally 
be  essentially  dependent  upon  the  previous  amount  of  fatty  tissue  in  the  body.  If  we 
bear  these  conditions  in  mind,  then  it  seems,  according  to  Bohtlingk,'  that,  from  ex- 
periments upon  white  mice,  the  animal  body  is  poorer  in  water  during  inanition.  The 
body  loses  more  water  than  is  set  free  by  the  destruction  of  the  tissues. 

The  mineral  substances  leave  the  body  uninterruptedly  in  starvation 
until  death,  and  the  influence  of  the  destruction  of  tissues  is  plainly  per- 
ceptible by  their  elimination.  Because  of  the  destruction  of  tissues  rich  in 
potassium  the  proportion  between  potassium  and  sodium  in  the  urine 
changes  in  starvation,  so  that,  contrary  to  the  normal  conditions,  the 
potassium  is  eliminated  in  proportionately  greater  quantities.  Munk  also 
observed  in  Cetti's'  case  a  relative  increase  in  the  phosphoric  acid  and 
calcium  in  the  urine  during  starvation,  which  was  due  to  an  increased 
exchange  of  bone-substance. 

Contrary  to  the  above,  Bohtlingk  found  in  white  mice  daring  starva- 
tion a  greater  eliminatioa  of  sodium  than  potassium.  Of  the  original 
quantity  43.46^  of  the  Na,0  and  8.41^  of  the  K,0  was  used.  Katsuyama  ' 
found  in  rabbits,  as  Bohtlingk  did  in  white  mice,  a  different  relationship 
between  potassium  and  sodium  in  the  urine  from  that  observed  by  Munk 
in  starving  human  beings.  The  relationship  of  these  two  bases  in  the  urine 
changes  in  the  first  3-8  days,  and  in  two  out  of  three  experiments  also  in 
the  following  days,  as  compared  with  the  first  two  days  of  starvation,  in 
favor  of  the  soda  elimination. 

The  question  as  to  the  participation  of  the  different  organs  in  the  loss 
of  weight  of  the  body  during  starvation  is  of  special  interest.  In  elucida- 
tion of  the  matter  we  have  given  on  the  next  page  the  results  of  Chossat's  ' 
experiments  on  pigeons,  and  those  of  Voit  *  on  a  male  cat.  The  results  are 
percentages  of  weight  lost  from  the  original  weight  of  the  organ. 

Sedlmair  '  has  studied  the  diminution  in  the  organs,  but  especially  in 
the  bones  of  cats,  in  starvation.  He  found  in  a  cat  which  had  starved  36  days 
a  loss  of  about  Ifo  in  the  bone-substance.  The  bones  in  starvation  become 
somewhat  richer  in  water,  and  the  amount  of  dry  substance  also  diminishes, 
taken  absolutely.     The  loss  in  dry  substance  consisted  in  greatest  part, 


'  Arch.  d.  scienc.  biol.  de  St.  Petersbourg,  Tome  5. 
«  Berlin,  klin.  Wochenschr.,  1887. 
«  Zeitschr.  f.  physiol.  Chem.,  Bd.  26. 

'  Cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6,  Thl.  1,  S.  96  and  97. 
Zeitschr   f.  Biologic,  Bd.  37. 


METABOLISM  IN  STARVATION.  561 

Table  IV. 

Pigeon  (Chossat).  Male  Cat  (Voir). 

Adipose  tis8ue 93  per  cent.  97  per  cent. 

Spleen 71       "  67       " 

Pancreas 64       "  17 

Liver 52       "  54       " 

Heiiit 45       "  3 

Intestine 42       "  18 

Muscles 42       "  31 

Testicles —  40 

Skin 33      "  21 

Kidneys 33       "  26 

Lungs  22       "  18       " 

Bones 17       "  14       " 

Nervous  system 2       "  3       " 

in  fact  |-|  of  fat;  bnt  the  other  constitnents  also  take  part  therein,  ossein 
with  -^^-\  and  the  bone-earths  with  ^V~i' 

The  total  quantity  of  blood,  as  well  as  the  quantity  of  solids  contained 
therein,  decreases,  as  Panuii  '  has  shown,  in  the  same  proportion  as  the 
weight  of  tlie  body.  The  statements  in  regard  to  the  loss  of  water  by 
different  organs  are  somewhat  contradictory;  according  to  Luk.tanow "  it 
seems  that  the  various  organs  act  somewhat  differently  in  this  respect. 

The  above-tabulated  results  cannot  serve  as  a  measure  of  the  metabolism 
in  the  various  organs  during  starvation.  For  instance,  the  nervous  system 
shows  only  a  small  loss  of  weight  as  compared  with  the  other  organs,  but 
from  this  it  must  not  be  concluded  that  the  exchange  of  material  in  this 
system  of  organs  is  least  active.  The  condition  may  be  quite  different;  for 
one  organ  may  derive  its  nutriment  during  starvation  from  some  other 
organ  and  exist  at  its  expense.  A  positive  conclusion  cannot  be  drawn  in 
regard  to  the  activity  of  the  metabolism  in  an  organ  from  the  loss  of  weight 
of  that  organ  in  starvation. 

The  knowledge  of  metabolism  during  starvation  is  of  the  greatest  im- 
portance in  the  study  of  nutrition,  and  it  forms  to  a  certain  extent  the 
starting-point  for  the  study  of  metabolism  under  different  physiological  and 
pathological  conditions.  To  answer  the  question  whether  the  metabolism 
of  a  person  in  a  special  case  is  abnormally  increased  or  diminished  it  is 
naturally  very  important  to  know  the  average  extent  of  metabolism  of  a 
healtliy  person  under  the  same  circumstances,  for  comparison.  This  quan- 
tity can  be  called  the  abstinent  value,  that  is,  the  extent  of  metabolism 
used  in  absolute  bodily  rest  and  inactivity  of  the  intestinal  tract.  As 
measure  of  this  quantity  we  determine,  according  to  Geppert-Zuntz,  the 
extent  of  gaseous  exchange,  and  especially  the  consumption  of  oxygen,  of  a 
person  lying  down,  best  sleeping,  in  the  early  morning  and  at  least  12 
hours   after   a   light   meal   not   rich  in  carbohydrates.     The  gas  volume 

'  Panuni,  Vircbow's  Arch.,  Bd.  29 ;  London,  Arcb.  d.  scienc.  biol.  de  St.  Peters- 
bourg.  Tome  4. 

»  Zeitscbr.  f.  physiol.  Chem.,  Bd.  13. 


562  METABOLISM. 

reduced,  to  0°  C.  and  760  mm.  Hg  pressure  is  calculated  on  1  kilo  of  bodjr 
weight  and  for  1  minute.  The  results  vary  between  3  and  4.5  for  the 
consumption  of  oxygen,  and  between  2.5  and  3.5  c.c.  for  the  carbon  dioxide. 
As  average  we  can  accept  3.81  c.c.  oxygen  and  3.08  c.c.  carbon  dioxide.' 

The  extent  of  proteid  destruction  cannot  be  determined  in  transient 
experiments,  and  for  these  reasons  only  the  values  found  after  several  days 
of  starvation  are  useful.  In  the  starvation  experiments  on  Cetti  and 
Succi  the  elimination  of  nitrogen  per  kilo  in  the  fifth  to  the  tenth  starva- 
tion day  was  0.150-0.202  grm.  N. 

III.  Metabolism  with  Inadequate  ISTutrition. 

The  food  may  be  quantitatively  insufficient,  and  the  final  result  is 
absolute  inanition.  The  food  may  also  be  qualitatively  insufficient  or,  as 
we  say,  inadequate.  This  occurs  when  any  of  the  necessary  nutritive  bodies 
are  absent  in  the  food,  while  the  others  occur  in  sufficient  or  perhaps  even 
in  excessive  amounts. 

Lach  of  Water  in  the  Food.  The  quantity  of  water  in  the  organism 
is  greatest  during  foetal  life,  and  then  decreases  with  increasing  age. 
Naturally,  the  quantity  differs  in  various  organs.  The  tissue  in  the  body 
being  poorest  in  water  is  the  enamel,  which  is  almost  free,  containing  only 
2  p.  m.  water,  the  teeth  about  100  p.  m.,  the  fatty  tissues  60=^120  p.  m. 
The  bones,  with  140-440  p.  m.,  and  the  cartilage,  with  540-740  p.  m.,  are 
somewhat  richer  in  water,  while  the  muscles,  blood,  and  glands,  with  750  to 
more  than  800  p.  m.,  are  still  richer.  The  quantity  of  water  is  even  greater 
in  the  animal  fluids  (see  preceding  chapter),  and  the  adult  body  contains  in 
all  about  630  p.  m.  water.^  If  we  bear  in  mind  that  two  thirds  of  the 
animal  organism  consists  of  water;  that  water  is  of  the  very  greatest  im- 
portance in  the  normal,  physical  composition  of  the  tissues;  moreover  that 
all  flow  of  Juices,  all  exchange  of  substance,  all  supply  of  nutrition,  all 
increase  or  destruction,  and  all  discharge  of  the  products  of  destruction,  are 
dependent  upon  the  presence  of  water;  and,  in  addition,  that  by  its  evapora- 
tion it  is  an  important  regulator  of  the  temperature  of  the  body,  we  perceive 
that  water  must  be  necessary  for  life.  If  the  loss  of  water  be  not  replaced 
by  fresh  supplies  sooner  or  later,  the  organism  succumbs. 

According  to  Landatjer^  the  partial  abstrtvction  of  water  causes  an  increased 
metiiholisin,  the  purpose  of  which  is  to  replace  some  of  the  abstracted  water  by  water 
produced  to  a  great  extent  iu  metabolism. 

Lach  of  Mineral  Substances  in  the  Food.  We  are  chiefly  indebted  to 
LiEBiG  for  showing  that  the  mineral  substances  are  just  as  necessary  for 

'  These  figures  are  taken  from  v.  Noorden's  Lehrbuch  der  Path,  des  Stoffwechsels, 
S.  94. 

«  See  Voit  in  Hermann's  Handbuch,  Bd.  6,  Thl.  1,  S.  345. 
*Maly'3  Jahresber.,  Bd.  34. 


LACK  OF  MINERAL  SUDSTANCEa.  563 

the  normal  composition  of  tlie  tissues  and  organs,  and  for  the  normal  course 
of  the  processes  of  life,  as  the  organic  constituents  of  tlie  body.  The  im- 
portance of  the  mineral  constituents  is  evident  from  tiie  fact  that  there  is 
no  animal  tissue  or  animal  fluid  which  does  not  contain  mineral  substance, 
and  also  from  the  fact  that  certain  tissues  or  elements  of  tissues  contain 
regularly  certain  mineral  substances  and  not  others,  which  explains  the 
unequal  division  of  the  potassium  and  sodium  compounds  in  the  tissues  and 
fluids.  With  the  exception  of  the  skeleton,  which  contains  about  220 
p.  m.  mineral  bodies  (Volkmann'),  the  animal  fluids  or  tissues  are  poor 
in  inorganic  constituents,  and  the  quantity  of  such  amounts,  as  a  rule,  only 
to  about  10  p.  m.  Of  the  total  quantity  of  mineral  sujastances  in  the 
organism,  the  greatest  part  occurs  in  the  skeleton,  830  p.  m.,  and  the  next 
greatest  in  the  muscles,  about  100  p.  m.  (Volkmann). 

Tlie  mineral  bodies  seem  to  be  partly  dissolved  in  the  fluids  and  partly 
combined  with  organic  substances.  In  accordance  with  this  the  organism 
persistently  retains,  with  food  poor  in  salts,  a  part  of  the  mineral  sub- 
stances, also  such  as  are  soluble,  as  the  chlorides.  On  the  burning  of  the 
organic  substances  the  mineral  bodies  combined  therewith  are  set  free  and 
may  be  eliminated.  It  is  also  admitted  that  they  in  part  combine  with  the 
new  products  of  the  combustion,  and  in  part  with  organic  nutritive  bodies 
poor  in  salts  or  nearly  salt-free,  which  are  absorbed  from  the  intestinal 
canal  and  are  thus  retained  (Voit,  Forster'). 

If  this  statement  be  correct,  it  is  possible  that  a  constant  supply  of 
mineral  substances  with  the  food  is  not  absolutely  necessary,  and  that  the 
amount  of  inorganic  bodies  which  must  be  administered  is  insignificant. 
The  question  whether  this  be  so  or  not  has  not,  especially  in  man,  been 
suflSciently  investigated;  but  generally  we  consider  the  need  of  mineral 
substances  by  man  as  very  small.  It  may,  however,  be  assumed  that  man 
usually  takes  with  his  food  a  considerable  excess  of  mineral  substances. 

Experiments  to  determine  the  action  of  an  insufficient  supply  of  mineral 
substances  with  the  food  in  animals  have  been  made  by  several  investigators, 
especially  Forster.  lie  observed,  on  experimenting  with  dogs  and  pigeons 
with  food  as  poor  as  possible  in  mineral  substances,  a  very  suggestive  dis- 
turbance of  the  functions  of  the  organs,  particularly  the  muscles  and  the 
nervous  system,  and  death  resulted  in  a  short  time,  earlier  in  fact  than  in 
complete  starvation.  In  opposition  to  these  observations  Buxge  has  sug- 
gested that  the  early  death  in  these  cases  was  not  caused  by  the  lack  of 
mineral  salts,  but  more  likely  by  the  lack  of  bases  necessary  to  neutralize 
the  sulphuric  acid  formed  in  the  combustion  of  the  proteids  in  the  organism,. 

'  See  Voit  in  Hermann's  Handbuch,  Bd.  6,  Tbl.  1,  S.  353. 

^  Forster,  Zeitscbr.  f.  Biologic,  Bd.  9.     See  also  Voit  in  Hermann's  Handbuch,  Bd. 
6,  Tbl.  1.  S.  354. 


564  METABOLISM. 

which  mast  then  be  taken  from  the  tissues.  In  accordance  with  this  view, 
BuxGE  and  Lunin"  '  also  found,  in  experimenting  with  mice,  that  animals 
which  received  nearly  ash-free  food  with  the  addition  of  sodium  carbonate 
were  kept  alive  twice  as  long  as  those  which  had  the  same  food  without 
the  sodium  carbonate.  Special  experiments  also  show  that  the  carbonate 
cannot  be  replaced  by  an  equivalent  amount  of  sodium  chloride,  and  that 
to  all  appearances  it  acts  by  combining  with  the  acids  formed  in  the  body. 
The  addition  of  alkali  carbonate  to  the  otherwise  nearly  ash-free  food  may 
indeed  delay  death,  but  cannot  prevent  it,  and  even  in  the  presence  of 
the  necessary  amount  of  bases  death  results  for  lack  of  mineral  substances 
in  the  food. 

In  the  above  series  of  experiments  made  by  *Bunge  the  food  of  the 
animal  consisted  of  casein,  milk-fat,  and  cane-sugar.  While  milk  alone 
was  an  adequate  and  sufficient  food  for  the  animal,  Bunge  found  that  the 
animal  could  not  be  kept  alive  longer  by  food  consisting  of  the  above  con- 
stituents of  milk  and  cane-sugar  with  the  addition  of  all  the  mineral 
substances  of  milk,  than  with  the  food  mentioned  in  the  above  experiments 
with  the  addition  of  alkali  carbonate.  The  question  wliether  this  result  is 
to  be  explained  by  the  fact  that  the  mineral  bodies  of  milk  are  chemically 
combined  with  the  organic  constituents  of  the  same  and  can  be  assimilated 
only  in  such  combinations,  or  whether  it  depends  on  other  nonditions, 
BuxGE  leaves  undecided.  These  observations,  however,  show  how  difficult 
it  is  to  draw  positive  conclusions  from  experiments  made  thus  far  with  food 
poor  in  salts.     Farther  investigations  on  this  subject  seem  to  be  necessary. 

With  an  insufficient  supply  of  chlorides  with  the  food  the  elimination 
of  chlorine  by  the  nrine  decreases  constantly,  and  at  last  it  may  stop 
entirely,  while  the  tissues  still  persistently  retain  the  chlorides.  These  last 
are,  at  least  in  part,  combined  in  the  body  with  the  organic  substances 
which  retain  them.  If  there  be  a  lack  of  sodium  as  compared  with  potas- 
sium, or  if  there  be  an  excess  of  potassium  compounds  in  any  other  form 
than  KOI,  the  potassium  combinations  are  rejDlaced  in  the  organism  by 
NaCl,  so  that  new  potassium  and  sodium  compounds  are  produced  which 
are  voided  with  the  urine.  The  organism  becomes  poorer  in  NaCl,  which 
therefore  must  be  taken  in  greater  amounts  from  the  outside  (Bunge). 
This  occurs  habitually  in  herbivora,  and  in  man  with  vegetable  food  rich  in 
potash.  For  human  beings,  and  especially  for  the  poorer  classes  of  people 
who  live  chiefly  on  potatoes  and  foods  rich  in  potash,  common  salt  is, 
under  these  circumstances,  not  only  a  condiment,  but  a  necessary  addition 
to  the  food  (Buxge''). 

'  Bunge,  Lelirbuch  der  pbysiol.  Chem.,  4.  Aufl.,  S.  97  ;  Lunin,  Zeitschr.  f.  physioi. 
Chem..  Bd.  5. 

'  Zeilscbr.  f.  Biologic,  Bd.  9. 


LACK  OF  MINERAL  SUBSTANCES.  665 

Lach  of  Alkali  Carbonates  or  Buses  in  the  Food.  The  cliemical 
processes  in  tlie  organism  are  dependent  upon  the  presence  of  alkaline- 
reacting  tissue-Uiiids,  whose  alkaline  reaction  is  due  to  alkali  carljouates. 
The  alkali  carbonates  are  also  of  great  importance  not  only  as  a  solvent  for 
certain  proteid  bodies  and  as  constituents  of  certain  secretions,  such  as  the 
pancreatic  and  intestinal  juices,  but  they  are  also  a  means  of  transportation 
of  the  carbon  dioxide  in  the  blood.  It  is  therefore  easy  to  understand  that 
a  decrease  below  a  certain  point  in  tiie  quantity  of  alkali  carbonate  must 
endanger  life.  Such  a  decrease  not  only  occurs  with  lack  of  bases  in  the 
food  which  accelerates  death  by  a  relatively  great  production  of  acids  through 
the  burning  of  the  proteids,  bat  it  also  occurs  when  an  animal  is  given 
dilute  mineral  acids  for  a  period.  In  herbivora  the  fixed  alkalies  of  the 
tissues  combine  with  the  mineral  acids,  and  the  animal  succumbs  in  a  short 
time.  In  caruivora  (and  in  man)  the  bases  of  the  tissues  are  obstinately 
retained;  the  mineral  acids'  unite  with  the  ammonia  produced  by  the 
decomposition  of  the  proteids  or  their  cleavage  products,  and  carnivora  can 
therefore  be  kept  alive  for  a  longer  time. 

Lach  of  Earthy  Phosphates.  With  the  exception  of  the  importance  of 
the  alkaline  earths  as  carbonates  and  more  especially  as  phosphates  in  the 
physical  composition  of  certain  structures,  such  as  the  bones  and  teeth, 
their  physiological  importance  is  nearly  unknown.  The  occurrence  of 
earthy  phosphates  in  all  proteids,  and  the  great  importance  of  the  earthy 
phosphates  in  the  passage  of  the  proteids  from  a  soluble  to  a  coagulable  and 
solid  state,  make  it  probable  that  the  earthy  phosphates  j^lay  an  important 
part  in  the  organization  of  the  proteids.  The  action  which  an  insufficient 
supply  of  alkali-earths  with  the  food  causes  is  connected  with  the  interest- 
ing question  as  to  the  effect  of  this  lack  upon  the  bony  structure.  This 
action,  as  well  as  the  various  results  obtained  by  experiments  on  young  and 
old  animals,  has  already  been  spoken  of  in  Chapter  X,  to  which  we  refer 
the  reader. 

Lack  of  Iron.  As  iron  is  an  integral  constituent  of  hjemoglobin,  abso- 
lutely necessary  for  the  introduction  of  oxygen,  just  so  is  it  an  indispensable 
constituent  of  the  food.  In  iron  starvation  iron  is  continually  eliminated, 
even  though  in  diminished  amounts;  and  with  an  insufficient  supply  of  iron 
with  the  food  the  formation  of  hfemoglobin  decreases.  The  formation  of 
ha3moglobin  is  not  only  enhanced  by  the  supply  of  organically  combined 
iron,  but  also,  according  to  the  general  view,  by  inorganic  iron  preparations. 
The  various  divergent  statements  on  this  question  have  already  been  given 
in  a  previous  chapter  (on  the  Blood). 

In  the  absence  oi  protein  bodies  in  the  food  the  organism  must  nourish 
itself  by  its  own  protein  substances,  and  with  such  nutrition  it  must  earlier 
or  later  succumb.  By  the  exclusive  administration  of  fat  and  carbohydrates 
the  consumption  of  proteids  in  these  cases  is  very  considerably  reduced. 


566  METABOLISM. 

According  to  the  doctrine  of  C,  Voit,  which  has  been  defended  by  recent 
investigations  of  E.  Voit  and  Korkunoff,'  the  proteid  metabolism  is 
ns^er  so  slight  under  these  conditions  as  in  starvation.  According  to  several 
investigators,  snch  as  Hirschfeld,  Kumagawa,  Klemperer,  Munk, 
Rosenheim/  and  others,  the  proteid  metabolism  may  indeed,  with  exclusively 
fat  and  carbohydrate  diet,  be  smaller  than  in  complete  starvation.  In 
conformity  with  this  the  animal  may  be  kept  alive  longer  by  food  contain- 
ing only  non-nitrogenons  bodies  than  in  complete  starvation. 

The  absence  of  fats  and  carholiyclrates  in  the  food  affect  oarnivora  and 
herbivora  somewhat  differently.  It  is  not  known  whether  carnivora  can  be 
kept  alive  for  any  length  of  time  by  food  entirely  free  from  fat  and  carbo- 
hydrates. Bat  it  has  been  positively  demonstrated  that  they  can  be  kept 
alive  a  long  time  by  feeding  exclusively  with  meat  freed  as  much  as  possible 
from  visible  fat  (Pfluger').  Human  beings  and  herbivora,  on  the  con- 
trary, cannot  live  for  any  length  of  time  on  such  food.  On  one  side  they 
lose  the  property  of  digesting  and  assimilating  the  necessarily  large  amounts 
of  meat,  and  on  the  other  a  distaste  for  large  quantities  of  meat  or  proteids 
soon  appears. 

IV.  Metabolism  with  Various  Foods. 

For  the  carnivora,  as  above  stated,  meat  as  poor  as  possible  in  fat  may 
toe  a  complete  and  sufficient  food.  As  the  proteids  moreover  take~~a  special 
■place  among  the  organic  nutritive  bodies  by  the  quantity  of  nitrogen  they 
contain,  it  is  proper  that  we  first  describe  the  metabolism  with  an  exclnsively 
meat  diet. 

Metabolism  with  food  rich  in  proteids,  or  feeding  only  with  meat  as  poor 
in  fat  as  possible. 

By  an  increased  supply  of  jiroteids  their  catabolization  and  the  elimi- 
nation of  nitrogen  is  increased,  and  this  in  proportion  to  the  supply  of 
proteids. 

If  a  certain  quantity  of  meat  has  been  given  as  food  daily  to  carnivora 
and  the  quantity  is  suddenly  increased,  an  increased  catabolism  of  proteids, 
or  an  increase  in  the  quantity  of  nitrogen  eliminated,  is  the  result.  If  we 
feed  the  animal  daily  for  a  certain  time  with  larger  quantities  of  the  same 
meat,  we  find  that  a  part  of  the  proteids  accumulates  in  the  body,  but  this 
part  decreases  from  day  to  day,  while  there  ia  a  corresponding  daily  increase 
in  the  elimination  of  nitrogen.  In  this  way  a  nitrogenous  equilibrium  is 
established,  that  is,  the  total  quantity  of  nitrogen  eliminated  is  equal  to  the 

'  Zeilschr.  f.  Biologic,  Bd.  33. 

Mlirsolifeld,  Vircliow's  Arch.,  Bd.  114;  KumaL-^awa,  ibid.,  Bd.  116;  Klemperer, 
Zeitsclir.  f.  kliii.  Med.,  Bd.  16;  Muiik,  Du  Bois-Reymond's  Arch.,  1891  and  1896; 
Rosenheim,  ih!d..  1891,  and  Ptliiger's  Arch.,  Bd.  54. 

»Pliiiger'.s  Arch.,  Bd.  50. 


METABOLISM   WITH  FOOD  lilCU  IN  PliOTEIDS.  567 

quantity  of  nitrogen  In  the  absorbed  proteids  or  meat.  If,  on  the  contrary, 
an  animal  which  is  in  nitrogenous  equilibrium,  having  been  fed  on  large 
qaantities  of  meat,  is  suddenly  fed  with  a  small  quantity  of  meat  per  day, 
then  the  animal  gives  up  its  own  bodily  proteids,  the  amount  decreasing 
from  day  to  day.  The  elimination  of  nitrogen  and  the  catabolism  of 
proteids  decrease  constantly,  and  the  animal  may  in  this  case  also  pass  into 
nitrogenous  equilibrium,  or  nearly  into  this  condition.  These  relations  are 
illustrated  by  the  following  table  (Voit  ') : 


Table  V. 

Grms.  of  Meat  in  the  Food  per  Day. 

1... 

Before  the  Test.        During  the  Test. 

500                      1 nno 

2... 

1500 

1000 

Grms.  of  Flesh  metabolized  in  Body  per  Day. 

1 
1222 
1153 

2                       3                      4                       5                       6 

1310            1390            1410            1440            1450 
1086           1088           1080           1027 

7 

1500 

In  the  first  case  (1)  the  metabolism  of  flesh  before  the  beginning  of  the 
actual  experiment  on  feeding  with  500  grms.  meat  was  447  grms.,  and  it 
increased  considerably  on  the  first  day  of  the  experiment,  after  feeding  with 
1500  grms.  meat.  In  the  second  case  (2),  in  which  the  animal  was  pre- 
viously in  nitrogenous  equilibrium  with  1500  grms.  meat,  tlie  metabolism 
of  flesh  on  the  first  day  of  the  experiment,  with  only  1000  grms.  meat, 
decreased  considerably,  and  on  the  fifth  day  a  nearly  nitrogenous  equilib- 
rium was  obtained.  During  this  time  the  animal  gave  up  daily  some  of 
its  own  proteids.  Between  that  point  below  which  the  animal  loses  from 
its  own  weight  and  the  maximum,  which  seems  to  be  dependent  upon  the 
digestive  and  assimilative  capacity  of  the  intestinal  canal,  a  carnivore  may 
be  kept  in  nitrogenous  equilibrium  with  varying  quantities  of  proteids  in 
the  food. 

The  supply  of  proteids,  as  well  as  the  proteid  condition  of  the  body, 
affects  the  extent  of  the  proteid  metabolism.  A  body  which  has  become 
rich  in  jiroteids  by  a  previous  abundant  meat  diet  must,  to  prevent  a  loss 
of  proteids,  take  up  more  proteid  with  the  food  than  a  body  poor  in 
proteids. 

Pettenkofer  and  Yoit  have  made  investigations  on  the  metabolism 
of  fat  with  an  exclusively  jiroteid  diet.  These  investigations  have  shown 
that  by  increasing  the  quantity  of  proteids  in  the  food  the  daily  meta- 
bolism of  fat  decreases,  and  they  have  drawn  the  conclusion  from 
these  experiments,  as  detailed  in  Chapter  X,  that  even  a  formation  of  fat 
may  take  place  under  these  circumstances.     The  objections  presented  by 


'  Hermauu'3  Ilandbuch.  Bd.  6,  Tbl.  1.  S.  110. 


568  METABOLISM. 

Pfluger  to  these  experiments,  as  well  as  the  proofs  of 'the  formation  of  fat 
from  proteids,  are  also  giv^en  in  the  above-mentioned  chapter. 

According  to  Pfluger's  doctrine  the  proteid  can  influence  the  forma- 
tion of  fat  only  in  an  indirect  way,  namely,  in  that  it  is  consumed  instead 
of  the  non-nitrogenous  bodies  and  hence  the  fat  and  fat-forming  carbo- 
hydrates are  spared.  If  sufficient  proteid  is  introduced  into  the  food  to 
satisfy  the  total  nutritive  requirements,  then  the  decomposition  of  fat 
stops;  and  if  non-nitrogenous  food  is  taken  at  the  same  time,  this  is  not 
consumed,  but  is  stored  up  in  the  animal  body,  the  fats  as  such,  and  the 
carbohydrates  at  least  in  great  part  as  fat. 

Pfluger  defines  the  "  nutritive  requirement  "  as  the  smallest  quantity 
of  lean  meat  which  produces  nitrogenous  eqnilibrinm  without  causing  any 
decomposition  of  fat  or  carbohydrates.  At  rest  and  at  an  average  tempera- 
ture it  is  found  for  dogs  to  be  2.073  to  2.099  grms.  nitrogen '  (in  meat  fed) 
per  kilo  of  flesh  weight  (not  bodily  weight,  as  the  fat,  which  often  forms  a 
considerable  fraction  of  the  weight  of  the  body,  cannot  as  it  were  be  used 
as  dead  measure).  Even  when  the  supply  of  proteid  is  in  excess  of  the 
nutritive  requirements,  Pfluger  has  found  that  the  proteid  metabolism 
increases  with  an  increased  supply  until  the  limit  of  digestive  power  is 
reached,  which  limit  is  about  2600  grms.  meat  with  a  dog  weighing  30 
kilos.  In  these  experiments  of  Pfluger's  all  of  the  excess  of  proteid 
introduced  was  not  completely  decomposed,  but  a  part  was  retai"ned  by  the 
body.  Pfluger  therefore  defends  the  proposition  "  that  a  supply  of 
proteids  only,  without  fat  or  carbohydrate,  does  not  exclude  a  proteid 
fattening." 

From  what  has  been  said  on  proteid  metabolism  in  starvation  and  with 
exclusive  proteid  food  it  follows  that  the  proteid  catabolism  in  the  animal 
body  never  stops,  that  the  extent  is  dependent  in  the  first  place  upon  the 
extent  of  proteid  supply,  and  that  the  animal  body  has  the  property,  within 
wide  limits,  of  accommodating  the  proteid  catabolism  to  the  proteid  supply. 

These  and  certain  other  peculiarities  of  proteid  catabolism  have  led 
VoiT  to  the  view  that  all  proteids  in  the  body  are  not  decomposed  with  the 
same  ease.  Voit  differentiates  the  proteids  fixed  in  the  tissue-elements, 
so-called  organized  proteids,  tissue-proteids,  from  those  proteids  which 
circulate  with  the  fluids  in  the  body  and  its  tissues  and  which  are  taken  up 
by  the  living  cells  of  the  tissues  from  the  interstitial  fluids  Avashing  them 
and  destroyed.  These  circulating  proteids  are,  according  to  Voit,  more 
easily  and  quickly  destroyed  than  the  tissne-proteids.  When,  therefore,  in 
a  fasting  animal  which  has  been  previously  fed  with  meat  an  abundant  and 
quickly  decreasing  decomposition  of  proteids  takes  place,  while  in  the 
further  course  of  starvation  this  proteid  catabolism  becomes  less  and  more 

'  See  Schondoril,  Pfluger's  Arch.,  Bd.  71. 


METABOLISM  WITH  FOOD  lilCU  IX  PliOTEIDS.  669 

uniform,  tliis  depends  upon  the  fact  that  the  supply  of  circulating^  proteids 
is  destroyed  chiefly  in  the  first  days  of  starvation  and  the  tissue-proteids  in 
the  last  days. 

The  tissue-elements  constitute  an  apparatus  of  a  relatively  stable  nature, 
which  have  the  power  of  taking  proteids  from  the  fluids  washing  the  tissues 
and  appropriating  them,  wliile  their  own  proteids,  the  tissue-proteids,  are 
ordinarily  catabolized  to  only  a  small  extent,  about  1^  daily  (Voit).  By 
an  increased  supply  of  proteids  the  activity  of  the  cells  and  their  ability  to 
decomjiose  nutritive  proteids  is  also  increased  to  a  certain  degree.  When 
nitrogenous  equilibrium  is  obtained  after  increased  supjily  of  proteids,  it 
denotes  that  the  decomposing  power  of  the  cells  for  proteids  has  increased 
so  that  the  same  quantity  of  proteids  is  metabolized  as  is  supplied  to  the 
body.  If  the  proteid  metabolism  is  decreased  by  the  simultaneous  adminis- 
tration of  other  non-nitrogenous  foods  (see  below),  a  part  of  the  circulating 
proteids  may  have  time  to  become  fixed  and  organized  by  the  tissues,  and 
in  this  way  the  mass  of  the  flesh  of  the  body  increases.  During  starvation 
or  with  lack  of  proteids  in  the  food  the  reverse  takes  place,  for  a  part  of 
the  tissue  proteids  is  converted  into  circulating  proteids  which  are  meta- 
bolized, and  in  this  case  the  flesh  of  the  body  decreases. 

Voit's  theory  has  been  severely  criticised  by  Pfluger.  Pfluger's 
statement,  based  on  an  investigation  made  by  one  of  his  pupils,  Schon"- 
DORFF,'  is  that  the  extent  of  proteid  destruction  is  not  dependent  upon 
the  quantity  of  circulating  proteids,  but  upon  the  nutritive  condition  of 
the  cells  for  the  time  being — a  view  which  is  not  very  contradictory  of 
YoiT  if  the  AUTHOR  does  not  misunderstand  Pfluger.  Voit'  has,  as  is 
known,  stated  that  the  conditions  for  the  destruction  of  substances  in 
the  body  exist  in  the  cells,  and  also  that  the  circulating  proteid,  likewise 
according  to  Yoix,  is  first  catabolized  after  having  been  taken  up  by 
the  cells  from  the  fluids  washing  them.  The  point  of  Voit's  theory 
is  that  all  proteids  are  not  destroyed  in  the  body  with  the  same  degree 
of  readiness.  The  organized  proteid,  which  is  fixed  by  the  cells  and 
has  become  a  part  of  the  same,  is  destroyed  less  readily,  according  to  Voit, 
than  the  proteid  taken  up  by  the  cells  from  the  nutritive  fluid,  which  serves 
as  material  for  the  chemical  construction  of  the  very  much  more  compli- 
cated organized  proteids.  This  nutritive  proteid,  which  circulates  with 
the  fluids  before  it  is  taken  up  by  the  cells,  and  which  can  exist  in 
store  in  the  cells  as  well  as  in  the  fluids,  agreeably  to  Voit's  view,  has 
been  called  circulating  proteid  or  supply  proteid  by  him.  It  is  clear  that 
these  names  may  lead  to  misunderstanding,  and  therefore  too  much  stress 
should  not  be  put  on  them.     Tlie  most  essential  part  of  Voit's  theory  is 

'  Pfluger,  Pfluger's  Arch.,  Bd.  54;  ScliOndorff,  ibid.,  Bd.  54. 
*  Zeitschr.  f.  Biologie,  Bd.  11. 


670  METABOLISM. 

the  supposition  that  the  food  proteid  of  the  cells  is  more  easily  destroyed 
than  the  organized,  real  protoplasmic  proteid,  and  this  assertion  can 
hardly,  for  the  present,  be  considered  as  refuted  or  exactly  proved. 

This  question  is  intimately  connected  with  another,  namely,  whether 
the  food  proteids  taken  up  by  the  cells  are  metabolized  as  such  or  whether 
they  are  first  organized.  The  investigations  of  Pajstum  and  Falck  '  on  the 
transitory  progress  of  the  elimination  of  urea  after  a  meal  rich  in  proteids 
throws  light  on  this  question.  From  experiments  upon  a  dog  it  was 
found  that  the  elimination  of  urea  increases  almost  immediately  after  a 
meal  rich  in  proteids,  and  that  it  reaches  its  maximum  in  about  six  hours, 
when  about  one  half  of  the  quantity  of  nitrogen  corresponding  to  the 
administered  proteids  is  eliminated.  If  we  also  recollect  that,  according  to 
an  experiment  of  Schmidt-Mulheim^  upon  a  dog,  about  37,<^  of  the  given 
proteids  are  absorbed  in  the  first  two  hours  after  the  meal  and  about  59^  in 
the  course  of  the  first  six  hours,  we  may  then  infer  that  the  increased 
elimination  of  nitrogen  after  a  meal  is  due  to  a  catabolization  of  the 
digested  and  assimilated  proteids  of  the  food  not  previously  organized.  If 
we  admit  that  the  catabolized  proteid  must  have  been  organized,  then  the 
greatly  increased  elimination  of  nitrogen  after  a  meal  rich  in  proteids  sup- 
poses a  far  more  rapid  and  comprehensive  destruction  and  reconstruction  of 
the  tissues  than  has  been  generally  assumed. 

In  this  connection  we  must  recall  that,  according  to  the  very  interestiDg 
investigations  of  Riazantseff,  after  partaking  of  food  an  increased  nitro- 
gen elimination  depends  in  part  upon  the  increased  work  of  the  digestive 
glands.  This  follows  from  the  considerably  increased  nitrogen  elimination 
after  so-called  "  apparent  feeding"  (see  Chapter  IX),  but  has  also  been 
confirmed  by  Riazantzeff  °  in  other  ways.  In  close  connection  with 
this  stand  the  observations  of  Nencki  and  Zaleski*  on  the  free  forma- 
tion of  ammonia  in  the  cells  of  the  digestive  apparatus  during  the  digestion 
of  food  rich  in  proteids. 

It  has  been  stated  above  that  other  foods  may  decrease  the  catabolism 
of  proteids.  Gelatin  is  such  a  food.  Gelatin  and  the  gelatin- formers  do 
not  seem  to  be  converted  into  proteid  in  the  body,  and  this  last  cannot  be 
entirely  replaced  by  gelatin  in  the  food.  For  example,  if  a  dog  is  fed  on 
gelatin  and  fat,  its  body  sustains  a  loss  of  proteids  even  when  the  quantity 
of  gelatin  is  so  large  that  the  animal,  Avith  an  amount  of  fat  and  meat  con- 

'  Panum,  Nord.  Med.  Arkiv.,  Bd.  6  ;  Falck,  see  Ilennann's  Handbuch,  Bd.  6,  Thl.  1, 
S.  107.  For  further  statements  iu  regard  to  the  curve  of  nitrogeu  elimination  ia  man 
see  TscbeiiloflE,  Korrespond.  Blatt  Schweiz.  Aerzte,  1896 ;  Rosemanu,  Pfliiger's  Arch., 
Bd.  65,  aud  Veraguth,  Journ.  of.  Physiol.,  Vol.  21. 

«  Du  Buis-Reymond's  Arch.,  1879. 

^  Arch,  des  scieuc.  biol.  dc  St.  Petersbourg,  Tome  4,  p.  393. 

•*  See  foot-note  3,  page  471. 


ACTION  OF  GELATIN  ON  METABOLISM.  571 

tainiug  just  the  same  (luiiutity  of  nitrogen  as  the  gelatin  iu  question,  may 
remain  in  nitrogenous  e([uilibrium.  On  the  other  hand,  gelatin,  as  \'oit, 
Panum  and  Oeru.nl  '  have  shown,  has  a  great  value  as  a  means  of  sparing 
the  proteids,  ami  it  may  decrease  the  catabolism  of  proteids  to  a  still 
greater  extent  than  fats  and  carbohydates.  This  is  apparent  from  the 
following  summary  of  Voit's  experiments  upon  a  dog: 

Table  VI. 

Food  per  Day.  Flesh. 


Meat. 

Gelatin. 

Fat. 

Sugar. 

Catabolized. 

On  the  Body. 

400 

0 

200 

0 

450 

-  50 

400 

0 

0 

250 

439 

-  39 

400 

200 

0 

0 

256 

+  44 

I.  MuNK "  has  lately  arrived  at  similar  results  by  means  of  more  decisive 
experiments,  lie  found  in  dogs  that  on  a  mixed  diet  which  contained  3.7 
grms.  proteid  per  kilo  of  body,  of  which  hardly  3.6  grms.  was  catabolized, 
nearly  |  could  be  replaced  by  gelatin.  The  same  dog  catabolized  on  the 
second  day  of  starvation  three  times  as  much  proteid  as  with  the  gelatin 
feeding.  Munk  states  also  that  gelatin  has  a  much  greater  sparing  action 
on  proteids  than  the  fats  or  the  carbohydrates. 

This  ability  of  gelatin  to  spare  the  proteids  is  explained  by  Voit  by  the 
fact  that  the  gelatin  is  decomposed  instr>ad  of  a  part  of  the  circulating 
proteids,  whereby  a  part  of  this  last  may  be  organized. 

Gelatin  may  also  decrease  somewhat  the  consumption  of  fat,  although 
it  is  of  less  value  in  this  respect  than  the  carbohydrates. 

The  question  of  the  nutritive  value  ot  pepto)ies  stands  iu  close  relation- 
ship to  the  nutritive  value  of  the  proteids  and  gelatin.  Tiie  early  investiga- 
tions made  by  Maly,  Plos'z  and  Oyergyay,  and  Adamkiewicz  have  led  to 
the  conclusion  that  with  food  which  contains  no  proteids  besides  peptones 
(albumoses)  an  animal  may  not  only  preserve  its  nitrogenous  equilibrium, 
but  its  proteid  condition  may  even  increase.  According  to  recent  and  more 
exact  investigations  by  Pollitzer,  Zuntz,  and  Muxk  the  albumoses  have 
the  same  nutritive  value  as  proteids,  at  least  in  short  experiments.  Accord- 
ing to  Pollitzer  this  is  true  for  different  albumoses  as  well  as  for  true 
peptone;  but  this  does  not  correspond  with  the  experience  of  Ellixger,' 
who  finds  that  the  true  antipeptone  (gland  peptone)  is  not  able  to 
entirely  replace  proteids  or  to  prevent  the  loss  of  proteid  in  the  animal 
body.     On  the  contrary,  according  to  him,  it  has,  like  gelatin,  the  property 

'  Voit,  1.  c,  S.  123  ;  Panum  and  Ocrum,  Nord.  Med.  Arkiv.,  Bd.  11. 

'  Ptliiger's  Arch..  Bd.  58. 

^  Maly,  Pflliger's  Arch.,  Bd.  9;  Plos'z  and  Gyergyay,  ibid.,  Bd.  10;  Adanikiewicz, 
■"Die  Natiir  und  der  NiUirwerth  des  Peptons "  (Berlin,  1877);  Pollitzer,  Ptliiger's 
Arch.,  Bd.  37,  S.  301  ;  Zuutz,  ibid.,  Bd.  37,  S.  313  ;  :\Iuiik,  Ceutralbl.  f.  d.  med.  Wis- 
sensch.,  1889,  S.  20,  and  Deutsch.  med.  Wocheuschr.,  1889;  Elliuger,  Zeitschr.  f. 
Biologic,  Bd.  33. 


672  METABOLISM. 

of  sparing  proteids.  Yoit  '  long  ago  expressed  a  similar  view.  According 
to  him  the  albamoses  and  peptone  may  indeed  replace  the  proteids  for  a 
short  time,  but  not  permanently;  they  can  spare  the  proteids,  but  not  be 
converted  into  proteids. 

From  exjieriments  made  by  Weiske  and  others  on  herbivora  it  appears 
that  asparagin  may  spare  proteid  in  such  animals.  In  carnivora  (I.  Munk) 
and  in  mice  (Voit  and  Politis)  it  was  found  that  asparagin  has  only  a 
very  slight,  if  any,  sparing  action  on  the  proteids.  It  is  not  known  how  it 
acts  in  man.  According  to  Kellner  '  the  sparing  action  of  asparagin  is 
only  of  an  indirect  kind,  because  it  serves  as  nutrition  for  the  bacteria  in 
the  digestive  tract  instead  of  the  proteids. 

Metabolism  on  a  Diet  consisting  of  Proteid,  with  Fat  or  Carbohydrates. 
Eat  cannot  arrest  or  prevent  the  cataholism  of  proteids  ;  but  it  can  decrease 
it,  and  so  spare  the  proteids.  This  is  apparent  from  the  following  table  of 
Voit.'     A  is  the  average  for  three  days,  and  B  for  six  days. 

Table  VII. 
Food.  Flesh. 


Meat.  Fat.  Metabolized.       On  the  Body. 

A 1500  0  1512  -  12 

B 1500  150  1474  +26 

According  to  Voit  the  adipose  tissue  of  the  body  acts  like  the  food-fat, 
and  the  proteid-sparing  effect  of  the  former  may  be  added  to  that  of  the 
latter,  so  that  a  body  rich  in  fat  may  not  only  remain  in  nitrogenous 
equilibrium,  but  may  even  add  to  the  store  of  bodily  proteids,  while  in  a 
lean  body  with  the  same  food  containing  the  same  amount  of  proteids  and 
fat  there  would  be  a  loss  of  proteids.  In  a  body  rich  in  fat  a  greater 
quantity  of  proteids  is  protected  from  metabolism  by  a  certain  quantity  of 
fat  than  in  a  lean  body. 

Because  of  the  sparing  action  of  fats  an  animal  to  whose  food  fat  is 
added  may,  as  is  apparent  from  the  tables,  increase  its  store  of  joroteid 
with  a  quantity  of  meat  which  is  insuflBcient  to  preserve  nitrogenous 
equilibrium. 

Like  the  fats  the  carbohydrates  have  a  sparing  action  on  the  proteids. 
By  the  addition  of  carbohydrates  to  the  food  the  carnivore  not  only  remains 
in  nitrogenous  equilibrium,  but  the  same  quantity  of  meat  which  in  itself 
is  insufficient  and  which  without  carbohydrates  would  cause  a  loss  of  weight 


>  L.  c,  S.  394. 

'  Weiske,  Zeitschr.  f.  Biologie,  Bdd.  15  and  17,  and  Ceutralbl.  f.  d.  nied.  Wissensch., 
1890,  S.  945;  Muiik,  Vircliow's  Arch.,  Bdd.  94  and  98;  Politis,  Zeitschr.  f.  Biologie, 
Bd.  28.  See  also  Mautliner,  ihid.,  Bd.  28  ;  Gabriel,  ibid.,  Bd.  29  ;  and  Voit,  ibid.,  Bd. 
29,  S.  125  ;  Kellner,  Maly's  Jahresber.,  Bd.  27. 

'  Voit  in  Hermann's  Handbucli,  Bd.  6,  S.  130. 


LIMIT  OF  PROTEID   GATABOLISM.  573 

in  the  body  may  with  the  addition  of  carbohydrates  produce  a  deposit  of 
proteids.     This  is  apparent  from  the  following  table  :  ' 

Table  VIII. 

Food.  Flesh. 


Meat 

Fat. 

Sugar. 

Starch. 

500 

250 

500 

300 

•  •  • 

500 

200 

• .  . 

800 

250 

800 

200 

•  •  > 

2000 

200-300 

2000 

250 

tabolizeil. 

Oil  the  Body 

558 

-  58 

466 

+  34 

505 

-   5 

745 

+  55 

773 

+  27 

1792 

+  208 

1883 

+  117 

The  sparing  of  proteid  by  carbohydrate  is  greater,  as  shown  by  the  table, 
than  by  fats.  According  to  VoiT  the  first  is  on  an  average  ffb  and  the 
other  li,  of  the  administered  proteid  without  a  previous  addition  of  non- 
nitrogenous  bodies.  Increasing  quantities  of  carbohydrates  in  the  food 
decrease  the  proteid  metabolism  more  regularly  and  constantly  than  increas- 
ing quantities  of  fat. 

Because  of  this  great  proteid-sparing  action  of  carbohydrates  the 
lierbivora,  which  as  a  rule  partake  of  considerable  quantities  of  carbohydrates, 
assimilate  proteids  readily. 

The  law  as  to  the  increased  proteid  catabolism  with  increased  proteid 
supply  applies  also  to  food  consisting  of  proteid  with  fat  and  carbohydrates. 
In  these  cases  the  body  tries  to  adapt  its  proteid  catabolism  to  the  supply; 
and  when  the  daily  calorie  supply  is  completely  covered  by  the  food,  the 
organism  can,  within  wide  limits,  be  in  nitrogenous  equilibrium  Avith 
different  quantities  of  proteid. 

The  upper  limit  to  the  possible  proteid  catabolism  per  kilo  and  per  day 
has  only  been  determined  for  herbivora.  For  human  beings  it  is  not 
known,  and  its  determination  is  from  a  practical  standpoint  of  secondary 
importance.  What  is  more  important  is  to  ascertain  the  lower  limit,  and 
on  this  subject  we  have  several  experiments  upon  man  as  well  as  animals  by 
HiRSCHFELD,  KuMAf4AWA,  Klempeuer,  Muxk,  RosEXHEiii,'  and  others. 
It  follows  from  these  experiments  that  the  lower  limit  of  proteid  needed 
for  human  beings  for  a  week  or  less  is  about  30-40  grms.  proteid  or  0.4-0.6 
grm.  per  kilo  Avith  a  body  of  average  weight,  v.  Xookdex  *  considers 
0.6  grm.  proteid  (absorbed  proteid)  per  kilo  and  per  day  as  the  lower 
limit.  The  above-mentioned  figures  are  only  valid  for  short  series  of 
experiments;  still  we  have  the  observations  of  E.  Voit  and  Coxstaxtixidi  * 
on  the  diet  of  a  vegetarian  in  which  the  proteid  condition  was  kept  nearly 
but  not  completely  for  a  long  time  with  about  0.6  grm.  proteid  per  kilo. 

'  Voit  in  Hermann's  Handbuch,  Bd.  6,  S.  143. 

'  See  foot-note  2,  page  566. 

^  Gnindriss  einer  ^Methodik  der  Stoffwecbseluntersuchungen.     Berlin,  1892. 

^  Zeitschr.  f.  Biologic,  Bd.  25. 


574  METABOLISM. 

According  to  Voit's  normal  fignres,  which  will  be  spoken  of  below  for 
the  nutritive  need  of  man,  an  average  working  man  of  about  70  kilos 
weight  requires  on  a  mixed  diet  about  40  calories  per  kilo  (true  calories  or 
net  calories,  namely,  the  combustion  value  of  the  absorbed  foods).  In 
the  above  experiments  with  food  very  poor  in  proteid  the  demand  for 
calories  was  considerably  greater;  as,  for  instance,  in  certain  cases  it  was  51 
(Kumagawa)  or  even  73.5  calories  (Klemperee).  It  therefore  seems  as 
if  the  above  very  low  supply  of  proteid  was  only  possible  with  great  waste 
of  non-nitrogenous  food;  but  in  opposition  to  this  we  must  recall  that  in 
VoiT  and  Coxstak^tixidi's  experiments  ujDon  the  vegetarian,  who  for  years 
was  used  to  a  food  very  poor  in  proteid  and  rich  in  carbohydrate,  the 
calories  amounted  to  only  43.7  jjer  kilo.  It  is  an  open  question  how  a 
nitrogenous  equilibrium  can  exist  also  on  a  diet  very  poor  in  nitrogen,  when 
the  need  of  calories  is  only  Just  covered  by  the  total  supply. 

In  Muxk's  and  Kosexheim's  experiments  upon  dogs  the  food  poor  in 
proteids  must  have  raised  the  total  supply  of  calories  considerably.  These 
experiments  also  teach  that  in  dogs  the  continuous  administration  for  a  long 
time  of  food  poor  in  proteid  has  an  action  on  the  health  of  the  animal  and 
may  even  cause  death.  In  the  experiments  published  by  Eosenheim, 
which  extended  over  two  months,  2  grms.  proteid  per  kilo  of  body  was  not 
sufficient  to  keep  the  animal  healthy,  although  the  heat  value  of  the  food 
taken  up  amounted  to  110  calories  per  kilo. 

The  very  important  question  as  to  the  conditions  favoring  the  deposition 
of  fat  and  flesh  on  the  body  is  closely  associated  with  what  has  just  been 
said  in  regard  to  foods  consisting  of  proteid  and  non-nitrogenous  food-stuffs. 
In  this  connection  we  mnst  recall  in  the  first  place  that  all  fattening  pre- 
supposes an  overfeeding,  i.e.,  a  supply  of  food-staffs  which  is  greater  than 
that  catabolized  in  the  same  time. 

In  carnivora,  as  shown  by  the  investigations  of  A^oit  and  Pfluger,  a 
very  inconsiderable  deposition  of  flesh,  in  proportion  to  the  catabolized 
proteid,  may  take  place  with  food  consisting  exclusively  of  meat.  In  man 
and  herbivora,  on  the  contrary,  the  demand  for  calories  may  not  be  covered 
by  proteid  alone,  and  the  question  as  to  the  conditions  of  fattening  with  a 
mixed  diet  is  of  importance. 

These  conditions  have  also  been  studied  in  carnivora,  and  here,  as  Voit  . 
has  shown,  the  relationship  between  proteid  and  fat  (and  carbohydrates) 
is  of  great  importance.  If  much  fat  is  given  in  proportion  to  the  proteid 
of  the  food,  as  with  average  quantities  of  meat  with  considerable  addition 
of  fat,  then  nitrogenous  equilibrium  is  only  slowly  attained  and  the 
daily  deposit  of  flesh,  though  not  large,  is  quite  constant,  and  may  become 
greater  in  the  course  of  time.  If,  on  the  contrary,  much  meat  besides 
proportionately  little  fat  is  given,  then  the  deposit  of  proteid  with  increased 
catabolism  is  smaller  day  by  day,  and  nitrogenous  equilibrium  is  attained 


DEPOSITION  OF  FLESU. 


675 


in  a  few  days.  In  spite  of  tlie  daily  somewhat  larger  deposit,  the  tot;.l 
flesh  deposit  is  not  considerable  in  these  cases.  The  following  experiment 
of  VoiT  may  serve  as  example: 

Taisle  IX. 


Number  of  Days 

of  Experimeuta- 

tion. 

Food. 

Total 

Deposit  of 

Flesh. 

Dailv 

Deposit  of 

Flesh. 

Nitrogenous 
Equilibrium. 

Meat,  grms. 

Fat,  grms. 

32 

7 

500 
1800 

250 
250 

1792 
854 

56 
122 

not  attained 
attaiued 

The  greatest  absolute  deposition  of  flesh  in  the  body  was  obtained  in 
these  cases  with  only  500  grnis.  meat  and  250  grms.  fat,  and  even  after  32 
days  the  nitrogenous  equilibrium  had  not  occurred.  On  feeding  with  1800 
grms.  meat  and  250  grms.  fat  the  nitrogenous  equilibrium  occurred  after 
7  days;  and  though  the  deposition  of  flesh  per  day  was  greater,  still  the 
absolute  deposit  was  not  one  lialf  as  gre^t  as  in  the  former  case.  Inasmuch 
as  the  quantity  of  proteids  does  not  decrease  below  a  certain  amount,  it 
seems  that  the  most  abundant  and  most  lasting  deposition  of  flesh  is 
obtained  with  a  food  which  does  not  contain  too  much  proteids  in  propor- 
tion to  the  fat.  The  same  is  also  true  of  a  diet  consisting  of  proteids  and 
carbohydrates. 

The  experiments  of  Krug  '  upon  himself,  under  the  direction  of  v.  Xoor- 
DEN,  give  us  information  as  to  the  practicability  of  flesh  deposition  in  man. 
With  abundant  food  (2590  cal.  =  44  cal.  per  kilo)  Krug  was  close  to 
nitrogenous  equilibrium  for  six  days.  He  then  increased  the  nutritive 
supply  to  4300  cal.  =71  cal.  per  kilo  for  15  days  by  the  addition  of  fat  and 
carbohydrate,  and  in  this  time  309  grms.  proteid,  corresponding  to  1455 
grms.  muscle,  was  spared.  Of  the  excess  of  administered  calories  in  this 
case  only  5^  was  used  for  flesh  deposit  and  95,^^  for  fat  deposit.  As  the 
large,  excessive  quantity  of  food  was  not  habitual,  and  eaten  with  reluctance, 
this  experiment,  as  Y.  Xoordex  has  correctly  emphasized,  has  placed  the 
difficulty  of  flesh  deposition  in  another  light.  We  must  admit  with 
V.  Xoordex  that  it  is  impossible  to  produce  a  permanent  flesh  deposit  in 
man  by  overfeeding,  and  that  it  is  not  possible  to  make  a  person  muscle- 
strong  by  excessive  feeding. 

Flesh  deposition  is,  according  to  v.  Noordex,  a  function  of  the  specific 
energy  of  the  developing  cells  and  the  cell-work  to  a  much  higher  extent 
than  the  excess  of  food.  Therefore  we  observe,  according  to  v.  Noorden, 
abundant  flesh  Reposition  (1)  in  each  growing  body;  (2)  in  those  no  longer 

'  Cited  from  v.  Noorden's  Lebrbuch  der  Patb.  des  Stoffwecbsels.  Berlin,  1893 
S.  120. 


576  ■  METABOLISM. 

growing  bat  whose  body  is  accustomed  to  increased  work  (hypertrophy  of 
the  mascles  by  work) ;  (3)  whenever,  by  previous  insufficient  food  or  by 
disease,  the  flesh  condition  of  the  body  has  been  diminished  and  therefore 
requires  abundant  food  to  replace  the  same.  The  deposition  of  flesh  is  in 
this  case  an  expression  of  the  regenerative  energy  of  the  cells. 

The  experiences  of  graziers  show  that  in  food-animals  a  flesh 
deposit  does  not  occur,  or  at  least  is  only  inconsiderable,  on  overfeeding. 
The  individuality  and  the  race  of  the  animal  are  of  importance  for  flesh 
deposition. 

As  above  stated  (Chapter  X)  respecting  the  formation  of  fat  in  the  animal 
body,  the  most  essential  condition  for  a  fat  deposition  is  an  overfeeding  with 
non-nitrogenous  foods.  The  extent  of  fat  deposition  is  determined  by  the 
excess  of  administered  calories  over  those  used.  If  a  large  part  of  the 
calorie  demand  is  covered  by  proteid,  then  a  greater  part  of  the  simul- 
taneously given  non-nitrogenous  food-stufls  is  spared,  i.e.,  used  for  fat 
deposition.  But  as  proteid  and  fat  are  expensive  nutritive  bodies  as  com- 
pared with  carbohydrates,  the  sapply  of  greater  qnantities  of  carbohydrates 
is  important  for  fat  deposition.  The  body  decomposes  less  substance  at 
rest  than  during  activity.  Bodily  rest,  besides  a  proper  combination  of  the 
three  chief  groups  of  organic  foods,  is  therefore  also  an  essential  requisite 
for  an  abundant  fat  deposit.  __^^ 

Action  of  Certain  other  Bodies  on  Metabolism.  Water.  If  a  quantity 
in  excess  of  that  which  is  necessary  is  introduced  into  the  organism,  the 
excess  is  quickly  and  principally  eliminated  witli  the  urine.  This  increased 
elimination  of  urine  causes  in  fasting  animals  (YoiT,  Forster),  but  not  to 
any  appreciable  degree  in  animals  taking  food  (Seegest,  Salk.owski  and 
MujTK,  Mayer,  Dubelir'),  an  increased  elimination  of  urea.  The  reason 
for  this  increased  elimination  ia  to  be  found  in  the  fact  that  the  drinking 
of  much  water  causes  a  complete  washing  out  of  the  urea  from  the 
tissues.  Another  view,  which  is  defended  by  Voit,  is  that  because  of  the 
more  active  carrent  of  fluids  after  taking  large  quantities  of  water  an  in- 
creased metabolism  of  proteids  takes  place.  Voit  considers  this  explana- 
tion the  correct  one,  although  he  does  not  deny  that  by  the  liberal 
administration  of  water  a  more  complete  washing  out  of  the  urea  from  the 
tissues  takes  place. 

*In  regard  to  the  action  of  water  on  the  formation  of  fat  and  its  meta- 
bolism, the  view  that  the  free  drinking  of  water  is  favorable  for  the  deposi- 
tion of  fat  seems  to  be  generally  admitted,  while  the  drinking  of  only  very 
little  water  acts  against  its  formation. 

'  Voit,  Untersuch.  iiber  den  Einfluss  des  Kochsalzes,  etc.  (Mtinclieu,  1800);  Forster, 
cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6,  S.  153;  Seegeii,  Wieu.  Sitzungsber., 
Bd.  03;  Salkowski  and  Munk,  Virchow's  Arch.,  Bd.  71;  Mayer,  Zeitschr.  f.  klin. 
Med.,  Bd.  2  ;  Dubelir,  Zeitschr.  f.  Biologic,  Bd.  28. 


ACTION  OF  ALCOHOL   ON  METABOLISM.  577 

Salts.  The  excretion  of  urine,  even  when  no  great  quantities  of  water 
are  inihibed,  is  increased  by  common  salt,  and  at  the  same  time  the  elimina- 
tion of  urea  is  also  increased.  The  same  two  possibilities  may  be  considered 
for  this  last  as  in-the  action  of  water  on  tiie  excretion  of  urea.  The  experi- 
ments continued  for  a  long  time  by  VoiT,  in  which  the  absolute  increase  of 
the  elimination  of  urea  was  considerable  (lOG  grms.  in  49  days),  render  the 
conclusion  probable  that  common  salt  somewhat  increases  the  metabolism 
of  the  proteids.  Dtbelir  has  obtained  contrary  results,  which  he  considers 
was  due  to  giving  the  animal  larger  quantities  of  common  salt.  It  is 
possible  that  the  decomposition  activity  of  the  cells  may  be  reduced  on 
giving  large  quantities  of  salt.  According  to  Straub  '  tiie  true  action  of 
common  salt  (although  the  loss  of  water  caused  by  the  common-salt  diuresis 
is  replaced  from  the  beginning  by  drinking  water)  is  a  small  diminution  of 
the  proteid  decomposition.  Pugliese  and  CoGGiMiave  also  come  to  the 
conclusion  that  common  salt  in  sufficiently  large  doses  diminishes  the  elimi- 
nation of  nitrogen.  Certain  other  salts,  such  as  potassium  chloride,  sodium 
sulphate,  sodium  phosphate,  sodium  biborate,  nitrate,  salicylate,  and  others, 
Jiave  an  increased  action  on  the  metabolism  of  proteids. 

Alcohol.  The  question  as  to  how  far  the  alcohol  absorbed  in  the  intes- 
tinal canal  is  burnt  in  the  body,  or  whether  it  leaves  the  body  unchanged 
by  various  channels,  l^as  been  the  subject  of  much  discussion.  To  all 
appearances  the  greatest  part  of  the  alcohol  introduced  (95^)  is  burnt  'u\ 
the  body  (Subbotix,  Thudichum,  Bodlaxder,  Benedicenti').  As  the 
alcohol  has  a  high  calorific  value  (1  grm.  =  7  cal.),  then  the  question 
arises  whether  it  acts  sparingly  on  other  bodies,  and  whether  it  is  to  be 
considered  as  a  nutritive  body.  The  investigations  made  to  decide  this 
question  have  led  to  no  decisive  result.  In  the  experiments  on  the  elimina- 
tion of  nitrogen  in  human  beings  sometimes  a  diminished  (Hammoxd, 
E.  Smith,  Oberxier),  sometimes  an  unchanged  (Parkes  and  Woelo- 
"wicz  *),  while  in  other  cases  an  increased  (Forster  and  Romeyx  ')  elimina- 
tion of  nitrogen  was  observed  after  the  administration  of  small  amounts  of 
alcohol.  In  the  recent  experiments  of  Stammreicii  and  v.  Xoorden* 
alcohol  could  only  replace  the  isodynamic  quantity  of  non-nitrogenous  food- 
stuffs, without  an  essential  influence  on  the  proteid  condition  of  the  body, 
in  a  food  richer  in  proteid  than  ordinarily.     Miura  '  could  not  find  any 


'  Zuitsclir.  f.  Biologic,  Bd.  37. 

»  See  Maly's  Jahreshor.,  Bd.  26,  S.  729. 

^  Benedicenti,  Du  Bois-Reymoiid's  Arch.,  1896,  which  also  contains  the  literature. 

*  In  regiird  to  the  older  investigations  see  Voit  in  Hermann's  Handbuch,  Bd.  6,  S.  170. 
'  Maly's  Jahresber.,  Bd.  17,  S.  4jOO. 

*  V.  Noordeu,  "  Alkoliol  als  Sparmitlel,"  Berlin,  kliu.  Wochenschr.,  1891. 
'  Zeitschr.  f.  klin.  Med.,  Bd.  20. 


578  METABOLISM. 

sparing  action  on  proteids  by  alcoliol  in  his  experiments,  and  according  to 
him  alcoliol  cannot  replace  the  siaaring  action  of  carbohydrate  on  proteid. 

FoKKER  and  I.  Muistk^  found  in  dogs  after  the  administration  of  small 
quantities  of  alcohol  a  diminished,  and  after  large  quantities  an  increased, 
metabolism  of  proteids.  Chittenden,  Noeris,  and  E.  Smith  "^  make  the 
statement,  based  on  their  experiments  with  1.9,  2.3,  and  2.7  c.c.  alcohol 
per  kilo  of  dog  per  diem,  that  alcohol  acts  like  a  non-nitrogenous  nutritive 
body  iu  regard  to  its  sparing  action  on  proteids. 

Many  investigations  have  been  made  as  to  the  extent  of  exchange  of 
gas  in  animals  after  taking  alcohol.  The  results  in  these  cases  are  some- 
what different,  depending  upon  the  size  of  dose  and  the  kind  of  animal. 
In  an  experiment  upon  the  human  body  Zuntz,  and  likewise  Geppert,^ 
observed  no  essential  change  in  the  respiratory  exchange  of  gas  after  small, 
non-intoxicating  doses  of  alcohol.  As  alcohol  is  in  greatest  part  consumed 
in  the  body  and  the  exchange  of  gas  is  nevertheless  not  essentially  raised,  it 
seems  as  if  the  alcohol  diminishes  the  combustion  of  other  bodies  and 
therefore  has  a  sj)aring  value.  Corresponding  with  this,  as  is  well  known,  a 
deposition  of  fat  may  take  place  in  the  body  under  the  influence  of  alcohol. 
The  nutritive  value  of  alcohol  may  be  of  essential  importance  only  in  certain 
cases,  as  large  quantities  of  alcohol  taken  at  a  time,  or  the  continued  use  of 
smaller  quantities,  has  an  injurious  action  on  the  organism.  Alcohol  may 
therefore  be  regarded  as  a  foodstuff  only  in  exceptional  cases,  and^in  other 
respects  must  be  considered  as  an  article  of  luxury. 

Coffee  and  tea  have  no  positively  proved  action  on  the  exchange  of 
material,  and  their  importance  lies  chiefly  in  their  action  upon  the  nervous 
system.  It  is  impossible  to  enter  into  the  action  of  various  therapeutic 
agents  upon  metabolism. 


V.  The  Dependence  of  Metabolism  on  Other  Conditions. 

The  previously  mentioned  so-called  abstinence  value,  i.e.,  the  extent  of 
metabolism  with  absolute  bodily  rest  and  inactivity  of  the  intestinal  tract, 
serves  best  as  a  starting-point  for  the  study  of  metabolism  under  various 
external  circumstances.  The  metabolism  going  on  under  these  conditions 
leads  in  the  first  place  to  the  production  of  heat,  and  it  is  only  to  a  sub- 
ordinate degree  dependent  upon  the  work  of  the  circulatory  and  respiratory 
apparatus  and  the  activity  of  the  glands.     According  to  a  calculation  by 

'  Fokker,  cited  from  Voit  in  Hermann's  Handbucli,  Bd.  6,  S.  170;  Munk,  Du  Bois- 
Reymond's  Arch.,  1879. 

»  Journ.  of  Physiol.,  Vol.  12.  See  also  Donogany  and  Tibald,  Maly's  Jahrcsber., 
Bd.  24,  and  Strfjm,  ibid. 

*  Zuntz,  Maly's  Jahresber.,  Bd.  17  ;  Qeppert,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  32. 


AOE  AND  METABOLISM.  579 

ZuNTZ,'  only  10-20^  of  the  total  calories  of  the  abstinence  value  belongs  to 
the  circulation  and  respiration  work. 

The  magnitude  of  the  abstinence  value  depends  in  the  first  place  upon 
the  heat  production  necessary  to  cover  the  loss  of  heat,  and  this  heat  pro- 
duction is  in  turn  dependent  upon  tlie  relationship  between  the  weiglit  of 
body  and  the  surface  of  the  body. 

Weight  of  Body  and  Age.  The  greater  the  mass  of  the  body  the  greater 
the  absolute  consumption  of  material;  while  on  the  contrary,  other  things 
being  equal,  a  small  individual  of  the  same  species  of  animals  metabolizes 
absolutely  less,  but  relatively  more  as  compared  with  the  unit  of  the  weight 
of  the  body.  It  must  be  remarked  that  we  mean  flesh  weight  when  we  say 
body  weight.  The  extent  of  the  metabolism  is  dependent  upon  the 
quantity  of  living  cells,  and  a  very  fat  individual  therefore  decomposes  less 
substance  per  kilo  than  a  lean  person  of  the  same  weight  of  body.  In 
women,  who  generally  have  less  bodily  weight  and  a  greater  quantity  of  fat 
than  men,  the  metabolism  in  general  is  smaller,  and  the  latter  is  ordinarily 
about  \  of  that  of  men. 

Tiie  question  as  to  what  extent  gender  specially  influences  metabolism 
remains  to  be  investigated.  Tigerstedt  and  Souden  '  found  that  in 
the  young  the  carbon  dioxide  elimination,  per  kilo  of  body  weight  as  well  as 
per  square  metre  of  body  surface,  was  considerably  greater  in  males  than  in 
females  of  the  same  age  and  the  same  weight  of  body.  This  difference 
between  the  two  sexes  seems  to  disappear  gradually,  and  at  old  age  it  entirely 
disappears. 

The  essential  reason  why  small  animals  decompose  relatively  more  sub- 
stance, as  calculated  on  the  kilos  of  the  body,  than  large  ones  is  that 
the  smaller  animals  have  greater  bodily  surface  in  proportion  to  their  mass. 
On  this  account  the  loss  of  heat  is  greater,  which  causes  increased  heat  pro- 
duction, i.e.,  a  more  active  metabolism.  This  is  also  the  reason  why  young 
individuals  of  the  same  kind  show  a  relatively  greater  decomposition  than 
older  ones.  If  we  calculate  the  heat  production  and  carbon-dioxide  elimi- 
nation on  the  unit  of  surface  of  body,  we  find,  on  the  contrary,  as  the 
experiments  of  Hubxer  upon  human  beings  and  Richet'  upon  dogs  show> 
that  they  vary  only  very  little  from  a  certain  average  in  individuals  of 
dilferent  weights. 

According  to  Tigerstedt  and  Souden  the  greater  metabolism  in  young 
animals  depends  nevertheless  also  in  part  on  the  fact  that  in  tliese  indi- 
viduals  the   decomposition   in   itself   is   more   active  than  in  older  ones. 

'  Cited  from  v.  Noorden,  Lehrbucb,  S.  97. 
'  Skand.  Arch.  f.  Physiol.,  Bd.  6. 

•^  Rubuer,    Zeilschr.   f.   Biologie,    Bdd.  21  and  19 ;  Richet,  Arch,  de  Physiol.  (5), 
Tome  2. 


580  METABOLISM. 

The  period  of  growth  has  a  considerable  influence  on  the  extent  of  meta- 
bolism (in  man),  and  indeed  the  metabolism,  even  when  calculated  on  the 
unit  of  surface  of  body,  is  greater  in  youth  than  in  age.' 

The  more  active  metabolism  in  young  individuals  is  apparent  when  we 
measure  the  gaseous  exchange  as  well  as  the  elimination  of  nitrogen.  As 
example  of  the  elimination  of  urea  in  children  the  following  results  of 
Camerer'^  are  of  value: 

Table  X. 

Age.  Weight  of  Body  in  Kilos.  Urea  in  grms. 

Per  Day.  Per  Kilo. 

li  years 10.80  12.10  1.35 

3'  " 13.30  11.10  0.90 

5  "     16.20  12.87  0.76 

7  "     18.80  14.05  0.75 

9  "     25.10  17.27  0.69 

12i  "     32.60  17.79  0.54 

15  "     35.70  17.78  0.50 

In  adults  weighing  about  70  kilos  from  30  to  35  grms.  urea  per  day  is 
eliminated,  or  0.5  grm.  per  kilo.  At  about  15  years  of  age  the  destruction 
of  proteids  per  kilo  is  about  the  same  as  in  adults.  The  relatively  greater 
metabolism  of  proteids  in  young  individuals  is  explained  partly  by  the  fact 
that  the  metabolism  of  material  in  general  is  more  active  in  young  animals, 
and  partly  by  the  fact  that  young  animals  are  as  a  rule  poorer  in  fat  than 
those  full  grown.  — ..^ 

As  the  metabolism  may  be  kept  at  its  lowest  point  by  absolute  rest  of 
body  and  inactivity  of  the  intestinal  tract,  it  is  manifest  that  work  and  the 
taking  up  of  food  have  an  important  bearing  on  the  extent  of  metabolism. 

Rest  and  Work.  During  work  a  greater  quantity  of  potential  energy  is 
converted  into  living  force,  i.e.,  the  metabolism  is  increased  more  or  less  on 
account  of  work. 

As  explained  in  a  previous  chapter  (XI)  work,  according  to  the  generally 
accepted  view,  has  no  material  influence  on  the  elimination  of  nitrogen. 
It  is  nevertheless  true  that  several  investigators  have  observed  in  certain 
cases  an  increased  elimination  of  nitrogen;  but  these  observations  have 
been  explained  in  other  ways.  For  instance,  work  may,  when  it  is  con- 
nected with  violent  movements  of  the  body,  easily  cause  dyspnoea,  and 
this  last,  as  Frankel'  has  shown,  may  cause  an  increase  in  the  elimination 
of  nitrogen,  since  diminution  of  the  oxygen  supply  increases  the  proteid 
■metabolism.  In  others  series  of  experiments  the  quantity  of  carbohydrates 
.anil  fats  in  the  food  was  not  sufficient;  the  supply  of  fat  in  the  body 
was  decreased  thereby,  and  the  destruction  of  proteids  was  correspond- 
ingly increased.     Work  may  also   increase  the  appetite,  and   an    increase 

'  This  stntemeiit  is  disputed  by  Ciimerer,  Zeitschr.  f.  Biologie,  Bd.  33. 
2  Zeitschr.  f.  Biologie,  Bdd.  10  aud.  20. 
^  Virchow's  Arch  ,  Bdd.  67  u.  71. 


MUSCLE  ACTIVITY  AND   EXCHANQE  OF  GA.S.  .081 

in  the  elimination  of  nitrogen  may  be  caused  by  tlio  greater  quantity  of 
proteids  taiien.  According  to  the  generally  accepted  views  muscular  activity 
has  hardly  any  influence  on  the  metabolism  of  proteids. 

On  the  contrary,  work  lias  a  very  considerable  influence  on  the  elimina- 
tion of  carbon  dioxide  and  the  consumption  of  oxygen.  This  action,  which 
was  first  observed  by  Lavoisier,  has  recently  been  confirmed  l)v  many 
investigators.  Pettenkofek  and  Yoit'  have  made  investigations  on  a 
full-grown  man  as  to  the  metabolism  of  the  nitrogenous  as  well  as  of  the 
non-nitrogenous  bodies  during  rest  and  work,  partly  while  fasting  and 
partly  on  a  mixed  diet.  The  experiments  were  made  on  a  full-grown  man 
weighing  70  kilos.     The  results  are  contained  in  the  following  table: 

Table  XI. 

Consumption  of 
Proteids.        Fat.    Carbohydrates.    COj  eliminated.    O  consumed 

Fastin?         ^^«s^ '9  209  ...  716  761 

**^"°S  •••  (Work 75  380  ...  1187  1071 

Mixed  diet  \  ^^«^"' 13^  "^2  352  912  831 

Mixed  diet  I  ^^j.^ J3Y  J ^3  3^2  ^209  980 

In  these  cases  work  did  not  seem  to  have  any  influence  on  the  destruc- 
tion of  proteids,  while  the  gas  exchange  was  considerably  increased. 

ZuNTZ  and  his  pupils '  have  made  very  important  investigations  into  the 
extent  of  the  exchange  of  gas  as  a  measure  of  metabolism  during  work  aiul 
caused  by  work,  using  Zl'xtz-Geppert's  method  (see  page  544).  These 
investigations  not  only  siiow  the  important  influence  of  muscular  Avork  on 
the  decomposition  of  material,  but  they  also  show  in  a  very  instructive  way 
the  relationship  between  the  extent  of  metabolism  of  material  and  n?ef'il 
work  of  various  kinds.  We  can  only  refer  to  these  important  investigations, 
which  are  of  special  physiological  interest. 

The  action  of  muscular  work  on  the  gas  exchange  does  not  alone  appear 
with  hard  work.  From  the  researches  of  Speck  and  others  we  learn  th;it 
even  very  small,  apparently  quite  unessential  movements  may  increase  the 
production  of  carbon  dioxide  to  such  an  extent  that  by  not  observino-  these, 
as  in  numerous  older  experiments,  very  considerable  errors  may  creep  in. 
.ToHAXSSON '  has  also  made  experiments  upon  himself,  and  finds  that  on 
the  production  of  as  complete  a  muscle  inactivity  as  possible  the  ordinary 
amount  of  carbon   dioxide   (31.2  grms.  per  hour  at  rest  in  the  ordinary 

'  Zeitschr.  f.  Biologic,  Bd.  2. 

■See  the  works  of  Zuntz  and  Lehmanu,  Maly's  Jahresber. ,  Bd.  19;  Katzensteln, 
Pflager's  Arch.,  Bd.  49  ;  Loewy,  ibid.;  Zuntz,  ibid.,  Bd.  68,  and  espocinlly  the  large 
work  "  Untersucb.  Uber  den  Sloffweclisel  des  Pferdes  bei  Rube  und  Arbeit,"  Zuntz  aiul 
Hagemauu,  Berlin,  1898,  wbicb  also  contains  a  bibliography. 

*  Nord.  Med.  Arkiv.  Fcstband,  1897;  ills.)  Maly's  Jahresber.,  Bd.  27;  Specks 
"Physiol,  des  mcnschl.  Alhmens."     Leipzig,  1892. 


582  METABOLISM. 

sense)  may  be  reduced  nearly  one  third,  or  an  average  of  22  grms.  per 
hour. 

The  quantity  of  carbon  dioxide  eliminated  during  a  working  period  is 
uniformly  greater  than  the  quantity  of  oxygen  taken  up  at  the  same  time, 
and  hence  a  raising  of  the  respiratory  quotient  was  formerly  usually  con- 
sidered as  caused  by  work.  This  rise  does  not  seem  to  be  based  upon  the 
kind  of  chemical  processes  going  on  during  work,  as  we  have  a  series  of 
experiments  made  by  Zuntz,  Lehmann,  and  Katzexsteix  ^  in  which  the 
respiratory  quotient  remained  almost  wholly  unchanged  in  spite  of  work. 
According  to  Loewy''  the  combustion  processes  in  the  animal  body  go  on 
in  the  same  way  in  work  as  in  rest,  and  a  raising  of  the  respiratory  quotient 
(irrespective  of  the  transient  change  in  the  respiratory  mechanism)  takes 
place  only  with  insufficient  supply  of  oxygen  to  the  muscles,  as  in  contin- 
uous fatiguing  work  or  excessive  muscular  activity  for  a  brief  period,  also  with 
local  lack  of  oxygen  caused  by  excessive  work  of  certain  groajjs  of  muscles. 
This  varying  condition  of  the  respiratory  quotient  has  been  explained  by 
Katzenstein  by  the  statement  that  during  work  two  kinds  of  chemical 
processes  act  side  by  side.  The  one  depends  upon  the  work  which  is  con- 
nected with  the  production  of  carbon  dioxide  also  in  the  absence  of  free 
oxygen,  while  the  other  brings  about  the  regeneration  which  takes  place  by 
the  taking  up  of  oxygen.  When  these  two  chief  kinds  of  chemical  processes 
make  the  same  progress  the  respiratory  quotient  remains  unchanged  during 
work ;  if  by  hard  work  the  decomposition  is  increased  as  compared  with  the 
regeneration,  then  a  raising  of  the  respiratory  quotient  takes  place. 

The  theory  of  Loewy  and  Zuntz  that  the  raising  of  the  respiratory 
quotient  during  work  is  to  be  explained  by  an  insufficient  supply  of 
oxygen"  is  opposed  by  Laulanie.'  He  has  observed  the  reverse,  namely,  a 
diminution  in  the  respiratory  quotient  during  continuous,  excessive  work, 
and  this  is  not  reconcilable  with  the  above  statements.  According  to 
Laulanie,  who  considers  sugar  as  the  source  of  muscular  energy,  the  rise 
in  the  respiratory  quotient  is  due  to  an  increased  combustion  of  sugar. 
The  diminution  of  the  same  he  explains  by  a  re-formation  of  sugar  from  fat 
which  takes  place  at  the  same  time  and  is  accompanied  with  an  increased 
consumption  of  oxygen. 

In  sleep  metabolism  decreases  as  compared  with  that  during  waking, 
and  the  most  essential  reason  for  this  is  the  muscular  inactivity  during  sleep. 
The  investigations  of  Rubner  upon  a  dog,  and  of  Johansson  *  upon  human 


'  See  foot-note  2,  page  580. 
•^  PUager's  Arch.,  Bd.  49. 
3  Arch,  de  Physiol.  (5),  Tome  8,  p.  573. 

*  Rubner,  Ludwig-Festschr.,  1887;  Loewy,  Berl.  klin.  Wochenscbr.,  1891,  S.  434; 
Jobausson,  Skand.  Arch.  f.  Physiol.,  Bd.  8. 


ACTION  OF  EXTERNAL  TEMPERATURE.  583 

teings,  teach  ns  that  if  the  muscular  work  is  eliminated  the  metabolism 
during  waking  is  not  greater  than  in  sleep. 

The  action  of  lif/Iit  also  stands  in  close  connection  witii  the  question  of 
the  action  of  muscular  work.  It  seems  positively  proved  that  metabolism  is 
Micreased  under  the  influence  of  light.  Most  investigators,  such  as  Speck, 
LoEH,  and  Ewald,'  consider  that  this  increase  is  due  to  the  movements 
caused  by  the  light  or  an  increased  muscle  tonus.  Fubini  and  Beni- 
DiCENTi '  assume  that  the  increase  in  metabolism  due  to  light  is  independent 
of  the  movements.  They  base  this  assumption  on  experiments  made  on 
hibernating  animals. 

Mental  activity  does  not  seem  to  have  any  influence  on  metabolism. 

Action  of  the  External  Temjierature.  In  cold-blooded  animals  the  pro- 
duction of  carbon  dioxide  increases  and  decreases  with  the  rise  and  fall  of 
the  surrounding  temperature.  In  warm-blooded  animals  this  condition  is 
the  reverse.  By  the  investigations  of  Ludwig  and  Sanders-Ezx,  Pfluger 
and  his  pupils,  and  Duke  Charles  Theodore  of  Bavaria  and  others,'  it 
has  been  demonstrated  that  in  warm-blooded  animals  the  change  in  the 
external  temperature  has  different  results  according  as  the  animal's  own 
heat  remains  the  same  or  changes.  If  the  temperature  of  the  animal  sinks, 
the  elimination  of  carbon  dioxide  decreases;  if  the  temperature  rises,  tlie 
elimination  of  CO,  increases.  If,  on  the  contrary,  the  temperature  of  the 
body  remains  unchanged,  then  the  elimination  of  carbon  dioxide  increases 
with  a  louver  and  decreases  with  a  higher  external  temperature.  This  fact 
may  be  explained,  according  to  Pfluger  and  Zuntz,  by  the  statement  that 
the  low  temperature,  by  exciting  a  reflex  action  in  the  sensitive  nerves  of 
the  skin,  causes  an  increased  metabolism  in  the  muscles  with  an  increased 
production  of  heat,  affecting  the  temperature  of  the  body,  while  with  a 
higher  external  temperature  the  reverse  takes  place.  The  experiments 
made  upon  animals  are  somewhat  uncertain  for  several  reasons,  but  the 
determinations  of  the  oxygen  absorption,  as  well  as  the  elimination  of  CO,, 
made  by  Speck,  Loewy,  and  Johanssox  ^  in  human  beings,  have 
shown  that  cold  does  not  produce  any  essential  increase  in  the  metabolism 
of  man.  The  irritation  caused  by  cold  may  reflexly  cause  a  forced  respira- 
tion with  an  action  on  the  gas  exchange,  and  weak  reflex  muscular  move- 
ments, such  as  shivering,  trembling,  etc.,  may  cause  an  insignificant 
increase  in  the  elimination  of  carbon  dioxide;  in  complete  muscular  in- 
activity cold  seems  to  cause  no  increased  absorption  of  oxygen  or  increased 

'  Speck,  1.  c;  Loeb,  PflUger's  Arch.,  Bd.  43  ;  Ewald,  Journ  of  Physiol.,  Vol.  13. 

»  Cited  from  Maly's  Jahresber.,  Bd.  22,  S.  395. 

'  The  pertinent  literature  may  be  found  cited  by  Voit  in  Hermann's  Handbuch,  Bd. 
6,  and  also  by  Speck,  1.  c. 

*  Speck,  1.  c. ;  Loewy,  Pflvlger's  Arch.,  Bd.  46  ;  JobanssoD,  Skand.  Arch.  f.  Physiol., 
Bd.  7. 


584  METABOLISM. 

metabolism.  Etkman's  '  experiments  upon  inhabitants  of  the  tropics  also' 
sliow  the  same  result,  namely,  that  in  human  beings  no  apreciable  chemical 
heat  regulation  occurs. 

Metabolism  is  increased  by  the  partaking  of  food,  and  Zusttz'  has  cal- 
culated that  in  man  the  consumption  of  oxygen  is  raised  oq  an  average  15^ 
abov^e  the  amount  during  rest  for  about  6  hours  after  taking  a  moderately 
hearty  meal.  This  increase  in  the  metabolism  is  caused,  according  to  the 
generally  accepted  view  of  Speck,  probably  only  by  the  increased  work  of 
the  digestive  apparatus  on  the  partaking  of  food.  Rjasantzeff  has  shown 
that  the  extent  of  nitrogen  elimination  is  joroportional  to  the  intensity  of 
the  digestive  work. 

VI.  The  IVecessity  of  Food  by  Man  under  Various 

Conditions. 

Various  attempts  have  been  made  to  determine  the  daily  quantity  of 
organic  food  needed  by  man.  Certain  investigators  have  calculated,  from 
the  total  consumption  of  food  by  a  large  number  of  similarly  fed  individuals, 
soldier,  sailors,  laborers,  etc.,  the  average  quantity  of  foodstuffs  required 
per  head.  Others  have  calculated  the  daily  demand  of  food  from  the 
quantity  of  carbon  and  nitrogen  in  the  excreta.  Others,  again,  have  calcu- 
lated the  quantity  of  nutritive  material  in  a  diet  by  which  an  eqUitrbrium 
was  maintained  in  the  individual  for  one  or  several  days  between  the  con- 
sumption and  the  elimination  of  carbon  and  nitrogen.  Lastly,  others  still 
have  quantitatively  determined  during  a  period  of  several  days  the  organic 
foodstuffs  consumed  daily  -by  persons  of  various  occupations  who  cliose 
their  own  food,  by  which  they  were  well  nourished  and  rendered  fully 
capable  of  labor. 

Among  these  methods  a  few  are  not  quite  free  from  objection,  and  others 
have  not  as  yet  been  tried  ou  a  sufficiently  large  scale.  Nevertheless  the 
experiments  collected  thns  far  serve,  partly  because  of  their  number  and 
partly  because  of  the  methods,  to  correct  and  control  one  another,  and  also 
serve  as  a  good  starting-point  in  determining  the  diet  of  various  classes  and. 
similar  questions. 

If  the  quantity  of  foodstuff's  taken  daily  be  converted  into  calories 
produced  during  physiological  combustion,  Ave  then  obtain  some  idea  of 
the  sum  of  the  chemical  potential  energy  which  under  varying  con- 
ditions is  introduced  into  the  body.  It  must  not  be  forgotten  that  the 
food  is  never  completely  absorbed,  and  that  undigested  or  unabsorbed 
residues  are  always  expelled  from  the  body  with  the  faeces.     The  gross 

»  Viichow's  Arch.,  Bd.  133,  iind  Pfliiger's  Arch.,  Bd.  G4. 

'■' Zuiitz  and  Levy,  "  Beilrag  zur  Kenntuiss  d.  Verdaulichkeit,  etc.,  des  Brodes," 
Pfliiger's  Arch.,  Bd.  49. 


NECESSITY  OF  FOOD  IN  MAN.  ^8^ 

results  of  calories  calculated  from  the  food  taken  must  tlierefore,  according 
to  RriJNER,  be  diuiiniahod  at  least  8;;^. 

Tiie  following  suniuuiry  contains  certain  examples  of  the  quantity  of 
food  which  is  consumed  by  individuals  of  various  classes  under  different 
conditions.  In  the  last  column  we  also  find  the  quantity  of  living  force 
which  corresponds  to  the  quantity  of  food  in  question,  calculated  as  calories, 
with  the  above-stated  correction.  The  calories  are  therefore  net  results, 
while  the  figures  for  the  nutritive  bodies  are  gross  results. 

Table  XII. 

Proteids.      Fat.  hj^^aies  C'alories.        Authority. 

Soldier  (luring  peace . ..   119  40  529  2784  Playfair.' 

light  service 117  35  447  2424  Hildesheim. 

"       intifkl 146  46  504  2852 

Laborer 130  40  550  2903  ^NIolebchott. 

at  rest 137  72  352  2458  Pettenkofer  &  VoiT. 

Cabinet-maker  (40  years)...   131  68  494  2835  Porsteu.'^ 

Young  physician 127  89  362  260S 

134  102  292  2476 

Laborer.    133  95  422  2902 

Eiiirlish  smith 176  71  666  3780  Playfair. 

pugilist 288  88  93  2189 

Bavarian  wood-chopper. .. .  135  208  876  5589  Liebig. 

Laborer  in  Silesia 80  16  552  2518  Meineht.' 

Seamstress  in  London 54  29  292  1688  Playfair. 

Swedish  laborer 134  79  485  3019  Hulturen  &  Landergren.* 

Japanese  student 83  14  622  2779  P:i.ikman.' 

shopman 55  6  394  1744  'J'awaha.' 

It  is  evident  that  persons  of  essentially  different  weight  of  body  who  live 
under  unequal  external  conditions  must  need  essentially  different  food.  It 
is  also  to  be  expected  (and  this  is  confirmed  by  the  table)  that  not  only  the 
absolute  quantity  of  food  consumed  by  various  persons,  but  also  the  relative 
proportion  of  the  various  organic  nutritive  substances,  shows  considerable 
variation.  Results  for  the  daily  need  of  human  beings  in  general  cannot 
be  given.  For  certain  classes,  such  as  soldiers,  laborers,  etc.,  results  may 
be  given  which  are  valuable  for  the  calculation  of  the  daily  rations. 

Based  on  extensive  investigations  and  a  very  wide  experience,  ^'oIT  has 
proposed  the  following  average  quantities  for  the  daily  diet  of  adults: 

Proteids.  Fat.  Carbohydrates.    Calories. 

For  men 118  grms.  56  grms.  500  grms.  2810 

But    it    should   be  remarked    that    these  data  relate  to  a  man  weigh- 

'  In  regard  to  the  older  researches  cited  in  this  table  we  refer  the  reader  to  Voit  i;i 
Hermann's  Handbuch,  Bd.  6.  S.  519. 

«  Ibid.,  and  Zeitschr.  f.  Biologic,  Bd.  9. 

*  Armee-  und  Volksernilhrung.     Berlin,  1880. 

*  Untersuchung  liber  die  Eruilhruug  schwediscber  Arbeiter  bei  frei  gewahlter  Kos{ 
Stockholm.  1891.     Maly,  Jahresber.  Bd.  21. 

*  Cited  from  Kclluer  and  Mori  in  Zeitschr.  f.  Biologie,  Bd.  25. 


586  METABOLISM. 

ing  70  to  75  kilos  and  who  was  engaged  daily  for  ten  hours  in  not  too 
fatiguing  labor. 

The  qnaiitity  of  food  required  by  a  woman  engaged  in  moderate  work  is 
about  four  fifths  that  of  a  laboring  man,  and  we  may  consider  the  following 
■as  a  daily  diet  with  moderate  work: 

Proteids.  Fat.  Carbohydrates.    Calories. 

For  womea 94  gnus.  45  grms.  400  grms.  2340 

The  proportion  of  fat  to  carbohydrates  is  here  as  1  :  8-9.  Such  a  pro- 
portion occurs  often  in  the  food  of  the  poorer  classes,  while  the  ratio  in  the 
food  of  wealthier  persons  is  1  :  3-4.  The  maximum  quantity  of  carbo- 
hydrates in  the  food  must,  according  to  Voit,  not  be  abore  500  grms. ;  and 
as  the  carbohydrates  besides  coustitate  the  chief  part  of  the  often  very  bulky 
vegetable  foods,  it  has  been  suggested  for  this  and  other  grounds  to  increase 
the  quantity  of  fat  at  the  expense  of  the  carbohydrates  in  such  rations. 
But  because  of  the  high  price  of  fat  such  a  modification  cannot  always  be 
made. 

In  examining  the  above  numbers  for  the  daily  rations  it  must  not  be 
forgotten  tbat  the  figures  for  the  various  foodstuffs  are  gross  results.  They 
consequeutly  represent  the  quantity  of  these  which  must  be  taken  in,  and 
not  those  which  are  really  absorbed.  The  figures  for  the  calories  are,  on 
the  contrary,  net  results. 

The  various  foods  are,  as  is  well  known,  not  equally  digested  and 
absorbed,  and  in  general  the  vegetable  foods  are  less  completely  consumed 
than  animal  foods.  This  is  especially  true  of  the  proteids.  When,  there- 
fore, Voit,  as  above  stated,  calculates  the  daily  quantity  of  proteids  needed 
by  a  laborer  as  118  grms.,  he  starts  with  the  supposition  that  the  diet  is  a 
mixed  animal  and  vegetable  one,  and  also  that  of  the  above  118  grms. 
about  105  grms.  are  absorbed.  The  results  obtained  by  Pfluger  and  his 
pupils  BoHLAND  and  Bleibtreu  '  of  the  extent  of  the  metabolism  of 
proteids  in  man  with  an  optional  and  sufficient  diet  correspond  well  with 
the  above  figures,  when  the  unequal  weight  of  body  of  the  various  persons 
experimented  upon  is  sufficiently  considered. 

As  a  rule,  the  more  exclusively  a  vegetable  food  is  employed,  the 
smaller  is  the  quantity  of  proteids  in  the  same.  The  strictly  vegetable  diet 
of  certain  people,  as  that  of  the  Japanese  and  of  the  so-called  vegetarians, 
is  therefore  a  proof  that,  if  the  quantity  of  food  be  sufficient,  a  person  may 
exist  on  considerably  smaller  quantities  of  proteids  than  Voit  suggests.  It 
follows  from  the  investigations  of  IIiksciifeld,  Kumagav^^a,  and  Klem- 
PERER  (see  page  574)  that  a  nearly  complete  or  indeed  a  complete  nitroge- 
nous equilibrium  may  be  attained  by  the  sufficient  administration  of  non- 
nitrogenous  nutritive  bodies  with  relatively  very  small  quantities  of  proteids. 

>  Bohland,  Pfluger's  Arch.,  Bd.  36  ;  Bleibtreu,  ibid.,  Bd.  38. 


NECESSITY  OF  FOOD  IN  MAN.  587 

If  we  bear  in  mind  that  the  food  of  people  of  different  conntries  varies 
greatly,  and  that  the  individual  also  takes  essentially  different  nourishment 
accordinir  to  the  external  conditions  of  living  and  the  influence  of  climate, 
it  is  not  remarkable  that  a  person  accustomed  to  a  mixed  diet  can  exist  for 
some  time  on  a  strictly  vegetal)le  diet  deficient  in  proteids.  Xo  one  doubts 
the  ability  of  man  to  adapt  liimself  to  a  heterogeneouslj  composed  diet 
when  this  is  not  too  difficult  of  digestion  and  is  suflicient  in  quantity  ;  but 
this  ability  does  not  fnrnisb  a  good  reason  for  essentially  altering  the  figures 
suggested  by  \'oiT.  Although  man  may  be  satisfied  under  certain  circum- 
stances with  a  smaller  quantity  of  proteid  than  tiiat  calculated  by  Voit, 
still  it  does  not  follow  tliat  such  a  diet  is  also  the  most  serviceable.  Voit's 
figures  are  only  given  for  certain  cases  or  certain  categories  of  human  beings. 
It  is  apparent  that  other  figures  must  be  taken  for  other  cases,  and  it  is 
evident  that  the  daily  ration  given  by  Voit  as  necessary  for  a  laborer  must 
be  altered  slightly  for  other  countries  because  of  the  existing  conditions  in 
middle  Europe,  where  Voit  made  his  investigations.  The  numerous  com- 
pilations (of  Atwater  and  others ')  on  the  diet  of  different  families  in 
America  have  given  the  figures  97-113  grms.  proteid  for  a  man,  and  the 
very  careful  investigations  of  Hultgren"  and  Landergren"  have  shown 
that  the  laborer  in  Sweden  with  moderate  work  and  an  average  bodv 
weight  of  70.3  kilos,  with  optional  diet,  partakes  13-4  grms.  proteid,  79 
grms.  fat,  and  522  grms,  carbohydrates.  The  quantity  of  proteid  is  here 
greater  than  is  necessary  according  to  Voit.  On  the  other  hand  Lapicque" 
found  G7  grms.  proteid  for  Abyssinians  and  81  grms.  for  Malaysians  (per 
body  weight  of  70  kilos),  materially  lower  figures. 

If  we  compare  the  figures  of  Table  XII  with  the  average  figures  proposed 
by  Voit  for  the  daily  diet  of  a  laborer,  it  would  seem  at  the  first  glance  as 
if  the  consumed  food  in  certain  cases  was  considerably  in  excess  of  the  need, 
while  in  other  cases,  as  for  instance  that  of  a  seamstress  in  London,  it  was 
entirely  insufficient.  A  positive  conclusion  cannot,  therefore,  be  drawn  if 
we  do  not  know  the  weight  of  the  body,  as  well  as  the  labor  performed  by 
the  person,  and  also  the  conditions  of  living.  It  is  certainly  true  that  the 
amount  of  nutriment  required  by  the  body  is  not  directly  proportional  to 
the  bodily  weight,  for  a  small  body  consumes  relatively  more  substance  than 
a  larger  one,  and  varying  quantities  of  fat  may  also  cause  a  difference;  but 
a  large  body,  which  must  maintain  a  greater  quantity,  consumes  an  abso- 
lutely greater  quantity  of  substance  than  a  small  one,  and  in  estimating  the 
nutritive   need    one  must  also   always  consider  the   weight  of  the   body. 

'  Atwjiter,  Report  of  the  Storrs  Ai^ilc.  Expt.  Station,  Coun.,  1891-1895  and  1896; 
also  Nutrition  Investigiitious  at  the  University  of  Tennessee.  1896  and  1897;  U.  S. 
Depart,  of  Agriculture.  Bull.  53,  1898. 

'  Plultgren  and  Landergreu,  1.  c. ;  Lapicque,  Arch,  de  Ph3-siol.  (5),  Tome  6. 


588  METABOLISM. 

According  to  Voit,  the  diet  for  a  laborer  with  70  kilos  bodily  weight 
requires  40  calories  for  each  kilo.  Ordinarily  in  resting  human  beings 
the  nutritive  demand  is  generally  calculated  as  30  calories  per  kilo.  The 
minimum  figure  for  metabolism  during  sleep  and  in  as  complete  rest  as. 
possible  has  been  found  by  Sonden,  Tigerstedt  and  Johansson'  to  be 
24-25  calories. 

As  several  times  stated  above,  the  demands  of  the  body  for  nourishment 
vary  with  different  conditions  of  the  body.  Among  these  conditions  two 
are  especially  important,  namely,  work  and  rest. 

In  a  previons  chapter,  in  which  muscular  labor  was  spoken  of,  it  was 
seen  that  the  generally  accepted  view  is  that  non-nitrogenous  food  is  the 
most  essential,  if  not  the  sole,  source  of  muscular  force.  As  a  natural 
sequence  it  is  to  be  expected  that  in  activity  the  non-nitrogenous  foods, 
before  all  must  be  increased  in  the  daily  rations. 

Still  this  does  not  seem  to  hold  true  in  daily  experience.  It  is  a  well- 
known  fact  that  hard-working  individuals — men  and  animals — require  a 
greater  quantity  of  proteids  in  the  food  than  less  active  ones.  This  contra- 
diction is,  however,  only  apparent,  and  it  depends,  as  Voit  has  shown,  upon 
the  fact  that  individuals  used  to  violent  work  are  more  muscular.  For 
this  reason  a  person  performing  severe  muscular  labor  requires  food  contain- 
ing a  larger  proportion  of  proteids  than  an  individual  whose  occupation 
demands  less  violent  exertion.  Another  question  is,  how  sliould  the 
relative  and  absolute  quantity  of  food  be  changed  if  increased  exertion  be 
demanded  of  one  and  the  same  individual  ? 

An  answer  based  upon  experience  may  be  found  in  statistics  concerning 
the  maintenance  of  soldiers  in  peace  and  war.  Many  such  data  are  obtain- 
able. In  a  critical  examination  of  the  same  it  is  found  that  in  Avar  rations 
the  quantity  of  non-nitrogenous  bodies  as  compared  with  the  proteids 
is  only  increased  in  exceptional  cases,  while  usually  the  reverse  is  the  case. 
Even  in  these  cases  the  actual  proportion  does  not  correspond  with  the 
theoretical  demand,  upon  which,  however,  too  great  stress  must  not  be 
laid,  since  in  the  case  of  soldiers  in  the  field  many  other  circumstances 
are  to  be  considered,  such  as  the  volume  and  weight  of  the  food,  etc.,  etc., 
which  cannot  here  be  more  closely  discussed.  The  following  table  shows 
the  average  results  of  soldiers'  rations  in  war  and  peace  from  the  data  given 
for  various  countries."  These  average  results  also  include  the  figures  for 
Sweden. 


'  Sonden  and  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  Bd.  6  ;  .Johansson,  ibid.,  Bd.  7^ 
Tigerstedt,  Nord.  Med.  Arkiv.  Festbaud,  1897. 

'  Germany,  Austria,  Switzerland,  France,  Italy,  Rus.sia,  and  the  United  States. 


NECESSITY  OF  FOOD  IN  MAN.  589 

Table  XIII. 

A.  Peace  lUition.  6.  War  Ration. 

Proteids.       Fat.            Carb.  Proteids.  Fat.  Carb. 

Minimum 108            22            504  126  38  484 

Maximum. 165            97            731  197  95  688 

Meau 130            40            551  146  59  557 

Sweden 179          102            591  202  137  565 

If  we  do  not  consider  the  very  liberal  rations  for  the  soldier  in 
Sweden,  and  if  we  simply  adhere  to  the  above  mean  figures,  we  obtain  the 
following  results  for  the  daily  rations: 

Proteids.  Fat.  Carb.  Calories. 

In  peace 130  40  551  2900 

In  war 146  59  557  3250 

If  we  calculate  the  fat  in  its  equivalent  quantity  of  starch,  then  the 
relation  of  the  proteids  to  the  non-nitrogenous  foods  is: 

I II  peace 1  :  4. 97 

In  war 1  :4.79 

The  proportion  is  nearly  the  same  in  both  cases;  the  slight  difference 
which  occurs  shows  a  trifling  relative  increase  in  the  proteids  in  the  war 
ration.  On  the  contrary,  as  is  especially  apparent  from  the  total  of  the 
calories,  the  total  quantity  of  nutritive  bodies  is  greater  in  the  war  than  in 
the  peace  ration. 

As  more  work  requires  an  increase  in  the  absolute  quantity  of  food,  so 
the  quantity  of  food  must  be  diminished  when  little  work  is  performed. 
The  question  as  to  how  far  this  can  be  done  is  of  importance  in  regard  to 
the  diet  in  prisons  and  poorhouses.  We  give  below  the  following  as  example 
of  such  diets: 

Table  XIV. 

Proteids.        Fat.  Carb.         Calories. 

Prisoner  (not  working) 87  22  305  1667  Schuster.' 

....  85  30  300  1709  Voit. 

Man  in  poorhouse 92  45  332  1985  Fokster.' 

Woman  in    '•         80  49  266  1725 

The  figures  given  by  Voit  are,  he  says,  the  lowest  reported  for  a  non- 
working  prisoner.  He  considers  the  following  as  the  lowest  diet  for  old 
non-  working  people : 

Proteids.         Fat.  Carb.  Calories. 

Men 90  40  350  2200 

Women 80  35  300  1733 

In  calculating  the  daily  diet  it  is  in  moat  cases  sufficient  to  ascertain 
how  much  of  the  various  foodstuffs  must  be  daily  administered  to  the 
body  to  keep  it  in  the  proper  condition  to  perform  the  work  required 
of  it.     In  other  cases  it  may  be  a  question  of  improving  the  nutritive  condi- 

'  See  Voit.  Untersucbung  der  Kost.     MUnchen,  1877.     S.  142. 
'  Ihid..  S.  186. 


690  METABOLISM. 

tion  of  the  body  by  properly  selected  food;  bat  we  also  have  cases  in  which 
it  is  desired  to  diminish  the  mass  or  weight  of  the  body  by  an  insufficient 
nutrition.  This  is  especially  the  case  in  obesity,  and  all  the  dietaries 
proposed  for  this  purpose  are  chiefly  starvation  cares. 

The  oldest  and  most  generally  known  diet  cure  for  corpulency  is  that  of 
Haevey,  which  is  ordinarily  called  the  Baxtixg  method.  The  principle 
of  this  cure  consists  in  increasing,  as  far  as  possible,  the  consumption  of  the 
accumulated  fat  of  the  body  by  as  limited  a  supjjly  of  fat  and  carbohydrates 
as  practicable  and  a  simultaneously  increased  supply  of  ^jroteids.  A  second, 
called  Ebstein's  cure,  is  based  on  the  assumption  (not  correct)  that  the  fat 
of  the  food  is  not  accumulated  in  a  body  rich  in  fat,  but  is  completely 
burnt.  In  this  cure  large  quantities  of  fat  are  therefore  allowed  in  the 
food,  while  the  quantity  of  carbohydrates  is  diminished  very  materially. 
The  third  cure,  called  Oertel's  '  cure,  is  based  on  the  correct  view  that  a 
certain  quantity  of  carbohydrates  has  no  greater  influence  in  the  accumula- 
tion of  fat  than  the  isodynamic  quantities  of  fat.  In  this  cure,  therefore, 
carbohydrates  as  well  as  fat  are  allowed,  provided  the  total  quantity  of  the 
same  is  not  so  great  as  to  hinder  the  decrease  in  the  fatty  condition.  A 
greatly  diminished  supply  of  water  is  also  one  of  the  features  of  Oertel's 
cure,  especially  in  certain  cases.  The  average  quantity  of  the  various 
nutritive  substances  supplied  to  the  body  in  these  three  cures  is  as  follows, 
and  we  give  also  for  comparison  in  the  same  table  Voit's  diet  ne'cessary  for 
a  laborer : 

Proteids.    Fat.       Carb.      Calories. 

Hakvey-Banting's  cure  171  8  75  1066 

Ebstein's  cure 102  85  47  1391 

Oertel's     "    156  22  72  1124 

"    (max.) 170  44  114  1557 

Laborer,  according  to  VoiT 118  56  500  2810 

If  the  fat  in  all  cases  is  recalculated  in  starch,  then  the  proportion  of 
the  proteids  to  the  carbohydrates  is: 

Hakvet-Banting's  cure 100  :    54 

Ebstein's  cure 100  :  246 

Oertel's     "    100:80 

"    (max.) 100:129 

Laborer 100  :  540 

In  all  these  cures  for  corpulence  the  quantity  of  non-nitrogenous  bodies 
is  diminished  as  compared  with  the  proteids;  but  also  the  total  quantity 
of  food,  as  is  shown  by  the  number  of  calories,  is  considerably  diminished. 

Harvey-Banting's  cure  differs  from  the  others  in  a  relatively  very 
much  greater  quantity  of  proteids,  while  the  total  number  of  calories  in  it 


'  Banliug,  Letter  on  Corpulence.  London,  1864 ;— Ebsteiu,  Die  Fettliebigkeit  und 
ilire  Bebaudlung.  1882  ;— Oertel,  Handbuch  der  allg.  Tberapie  der  Kreislaufstorungen. 
1884. 


DIET  CURES.  591 

is  tlie  smallest.  On  tliis  account  this  cure  acts  very  quickly;  but  it  ia 
tljerelore  also  more  dangerous  and  more  diflicult  to  accomplish.  In  this 
regard  Ebstkin's  and  Oertel's  cures  (especially  Oektel's),  having  a 
greater  variation  in  the  selection  of  food,  are  better.  As  the  adipose  tissue 
has  a  proteid-s]iaring  action,  we  have  to  consider  in  using  these  cures, 
esiK'cially  liANTixo's,  that  the  destruction  of  i)roteids  in  the  body  is  not 
increased  with  the  decrease  in  the  adipose  tissue,  and  one  must  therefore 
carefully  watch  the  elimination  of  nitrogen  by  the  urine.  All  diet  cures  fcr 
obesity  are  moreover,  as  above  stated,  starvation  cures;  and  if  the  daily 
quantity  of  food  required  by  an  adult  man,  represented  as  calories,  is  in 
round  numbers  2500  calories  (according  to  the  average  figures  found  by 
FoRSTER  in  the  case  of  a  physician),  then  one  immediately  sees  what  a  con- 
siderable part  of  its  own  mass  the  body  must  daily  give  up  in  the  above 
cures.  This  reminds  us  of  tlie  great  care  necessary  in  employing  them; 
each  special  case  should  be  conducted  with  regard  to  the  individuality,  the 
weight  of  the  body,  the  elimination  of  nitrogen  in  the  urine,  etc.,  etc.,  and 
always  under  strong  control,  and  only  by  a  physician,  never  by  a  layman.  A 
more  detailed  discussion  of  the  many  conditions  which  must  be  considered. 
in  these  cases  does  not  enter  into  the  plan  and  scope  of  this  work. 


592 


FOOD   TABLES. 
TABLE  L— FOODS/ 


1.  Animal  FoodstuflFs. 


a.  Flesh  withotjt  Bones. 

Pat  beef ' 

Beef  (average  fat ') 

Beef 

Coined  beef  (average  fat) 

Veal 

Horse,  salted  and  smoked 

Smoked  ham  

Pork,  salted  and  smoked  * 

Flesh  from  hare 

"         "     chicken 

"         "     partridge 

"         "     Avild  duck 

h.  Flesh  with  Bones. 

Fat  beef  = 

Beef,  average  fat  ^ 

Beef,  slightly  corned 

Beef,  thoroughly  corned 

Mutton,  very  fat 

' '        average  fat 

Pork,  fresh,  fat ,. 

Pork,  corned,  fat 

Smoked  hum 

c.  Fishes. 

River  eel,  fresh,  entire , 

Salmon,         "  "     , 

Anchovy,      "  "     

Flounder,      "  "     , 

River  perch,"  "     

Torsk,  "  "     

Pike.  "  '••     

Herring,  salted,  entire , 

Anchovy,     "  "      , 

Salmon  (side),  salted 

Kabel jau  (salted  haddock) , 

Codfish  (dried  ling) , 

(dried  torsk) 

Fish-meal  from  variety  of  Gadus 


1000  Parts  contain 

Eelationship 

1 

-i 

3 

4 

5 

6 

1 

:2 

"^  m 

5g^ 

P 
fc 

O 

4 

< 

6 
1 

183 

166 

11 

640 

100 

90 

196 

98 

18 

688 

100 

50 

190 

120 

18 

672 

100 

63 

218 

115 

117 

550 

100 

53 

190 

80 

13 

717 

100 

43 

318 

65 

125 

492 

100 

20 

255 

365 

100 

280 

100 

143 

100 

660 

40 

130 

100 

660 

233 

11 

12 

744 

100 

5 

195 

93 

11 

701 

100 

48 

253 

14 

14 

719 

100 

6, 

246 

31 

12 

711 

100 

13 

156 

141 

9 

544 

150 

100 

90 

167 

83 

15 

585 

150 

100 

49 

175 

93 

85 

480 

167 

100- 

^53 

190 

100 

100 

430 

180 

100 

53 

135 

332 

8 

437 

88 

100 

246 

160 

160 

10 

520 

150 

100 

100 

100 

460 

5 

365 

70 

100 

460 

120 

540 

60 

200 

80 

100 

450 

200 

300 

70 

340 

90 

100 

150 

89 

220 

6 

352 

333 

100 

246 

121 

67 

10 

469 

333 

100 

56 

128 

39 

11 

489 

333 

100 

31 

145 

14 

11 

580 

250 

100 

9 

100 

2 

8 

440 

450 

100 

2 

86 

1 

8 

455 

450 

100 

82 

1 

6 

461 

450 

100 

140 

140 

100 

280 

340 

100 

100 

116 

43 

107 

334 

400 

100 

37 

200 

108 

132 

460 

100 

100 

54 

246 

4 

178 

472 

100 

100 

532 

5 

106 

257 

100 

100 

665 

10 

59 

116 

150 

100 

736 

7 

87 

170 

100 

'The  results  in  the  following  tables  are  cliiefly  compiled  from  the  summary  of  AlmSn  and  of 
KoNio.  We  here  designate  as  "waste"  the  part  of  the  foods  which  is  lost  in  the  preparation  of  the 
food  or  that  which  is  not  used  by  the  body;  for  instance,  bones,  skin,  egg-shells,  and  the  cellulose 
vegetable  foods. 

^  Meat  such  as  is  ordinarily  sold  in  the  markets  in  Sweden. 

3  Bf-ef  such  as  is  delivered  by  large  purveyors  to  public  institutions  in  Sweden. 
Pork,  chiefly  from  the  breast  and  belly,  such  as  occurs  in  the  rations  of  Swedish  soldiers. 


ANIMAL  AND    VEGETABLE  FOODS. 
TABLE   I.— FOOD^.— {Continued.) 


693 


1.  Animal  FoodstuflFs. 


d.  Inner  Organs  (Fresh). 

Braiu   

Beef-liver 

Beef  heart 

Heiiit  aud  lungs  of  mutton 

Veal-kidney 

Ox  tongue  (fresh) 

Blood      from      various      animals 
(average  results) 

<'.  Other  Animal  Foods. 
Variety  of  pork-sausage(Mettwurst). 

Same  for  frying 

Butter 

Lard 

Meat  extract 

Cow's  milk  (full) 

"     (skimmed) 

Buttermilk 

Cream 

Cheese  (fat) 

(poor) 

Whey  cheese  (poor) 

Hen's  egg,  entire 

"        "    without  shell 

Yolk  of  egg 

White"     "  

2.  Vegetable  Foodstiiffs. 

Wheat  (grains) 

Wheat-ltlour  (fine) 

"  (very  fine) 

Wheat-bran 

Wheat- bread  (fresh) 

Macaroni 

Rye  (grains) 

Rye-tlour 

Bye-bread  (dry) 

(fresh,  coarse) 

"        "      (fresh,  fine) 

Barley  (grains) 

Scotch  barley 

Oat  (grains) 

Oat  (peeled) 

Corn 

Rice  f peeled  for  boiling) 

Frencli  beans 

Peas  (yellow  or  green,  dry)  . . . 

Flour  from  peas 

Potatoes 

Turnips 


1000  Parts  contain 

1 

•i 

3 

4 

5 

*  > 

^f' 

u 

5 

•Sf! 

•g 

< 

4) 

8^ 

5- 

t^Ui 

116 

103 

11 

770 

196 

56 

11 

17 

720 

184 

92 

10 

714 

163 

106 

10 

721 

221 

38 

13 

728 

150 

170 

10 

670 

182 

2 

9 

807 

190 

150 

50 

610 

220 

160 

55 

565 

7 

850 

7 

15 

119 

3 

990 

7 

304 

175 

217 

35 

35 

50 

7 

873 

35 

7 

50 

7 

901 

41 

9 

38 

7 

905 

37 

257 

35 

6 

665 

230 

270 

40 

60 

400 

334 

66 

50 

50 

500 

89 

70 

456 

56 

329 

106 

93 

4 

8 

654 

122 

107 

5 

10 

756 

160 

307 

13 

520 

103 

7 

7 

8 

875 

123 

17 

676 

18 

140 

110 

10 

740 

8 

120 

92 

11 

768 

3 

120 

150 

39 

439 

50 

130 

88 

10 

550 

17 

330 

90 

3 

768 

8 

131 

115 

17 

688 

18 

140 

115 

15 

720 

20 

110 

114 

20 

725 

15 

110 

77 

10 

480 

16 

400 

80 

14 

514 

11 

370 

111 

21 

654 

26 

140 

110 

10 

720 

7 

146 

117 

60 

563 

30 

130 

140 

60 

660 

20 

100 

101 

58 

656 

17 

140 

70 

7 

770 

2 

146 

232 

21 

537 

36 

137 

220 

15 

530 

25 

150 

270 

15 

520 

25 

125 

20 

2 

200 

10 

760 

14 

2 

74 

' 

893 

Relationship  of 


135 


26 
12 

6 
192 

5 

22 
20 
16 
17 

11 
48 

100 
20 
28 
5 
87 
60 
45 


100 
100 
100 
100 
100 
100 

100 

100 
100 
100 
100 

100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 


100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 


8  I  100 
10  100 


89 
28 
50 
65 
17 
113 


79 

73 

12100 

33000 


0 

0 

100 

0 


100  143 
20  143 


22 

695 

117 

19 

79 


192 

7 


93 
95 

17 
15 
512 
4 
4 
0 
7 


549 

654 

835 

26'  293 

111  625 

3  853 

15  600 

13  626 
18  634 

14  (i23 

18  634 

19  589 
9  654 


481 

471 

663 

1100 

9  231 

7i  240 

6  193 

J0  1030 

14:  529 


594 


FOOD   TABLES. 


TABLE   I.— FOOT>%— {Continued). 


1000  Parts  contain 

Relationship  of 

2.  Vegetable  FoodstuflFs. 

1 

xr.'Z 

-a  -J 

2 

1 

3 

u 

u  u 

6"^ 

4 

i 

5 

1 

6 
I 

1 

:3 

:3 

Cfirrot  (yellow)  

10 

25 

19 

27 

31 

14 

10 

12 

32 

219 

4 

5 

242 

140 

2 
4 
2 
1 
5 
3 
1 
1 
4 
25 

537 

480 

90 

50 

49 

66 

33 

22 

23 

38 

60 

412 

130 

90 

72 

180 

10 
8 

12 
6 

19 

10 
4 
7 
9 

61 
3 
6 

29 

50 

873 
904 
900 
888 
908 
944 
956 
9b4 
877 
160 
832 
849 
54 
55 

15 
9 
18 
12 
8 
7 
6 
8 

18 
123 
31 
50 
66 
95 

100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 

20 
16 

11 

4 
16 
21 
10 

8 
12 
12 

222 
343 

900 

Cauliflower     •• 

200 

C:ibbag6  

?15R 

\*.H 

Spinach.    

106 

Lettuce 

157 

Cucumbers 

230 

817 

Edible  mushrooms  (average) 

Same  dried  in  the  air  (average). . . 
Apples  and  pears 

188 

188 

3?50 

Various  berries  (average) 

1800 
30 

Cocoa 

129 

1 

TABLE   II.— MALT   LIQUORS. 


1000  Parts  by  "Weight  contain. 


Porter 

Beer  (Swedish) 

•'     (Swedish  export). . 

Draught-beer 

Lager-beer 

Bock  beer 

"Weiss-beer 

Swedish  "  Svagdricka" 


c 

"o 
Si 

8 
< 

1 

u 

CO 

"2 
"53 

2 

P4 

c 

a 

i 

a 

•u 

u 
>> 

5 

871 
887 

2 

54 

28 

76 

7 
15 

13 

3.0 

— 

65 

885 

32 

— 

7 

73 

— 

— 

911 

2 

35 

55 

8 

10 

31 

2.0 

2 

903 

2 

40 

58 

4 

7 

47 

1.5 

2 

881 

2 

47 

72 

6 

13 

— 

1.7 

— 

916 
945 

3 

25 
22 

59 

5 

7 

— 

— 

4.0 

— 

2 

3 

5 
3 
2 
2 
3 
2 

—        -        3 


WINES  AND   OTHER  ALCOHOLIC  LIQUORS. 


695 


TABLE    III— WINES   AND    OTHER  ALCOHOLIC    LIQUORS. 


1000  Parts  by  Weight 
contain. 


Bordeaux  wiDe 

White  wine  (Rheingau). . 

CLampagne 

Kiiiue  wine  ^sparkling). . 

Tokay 

Sherry   

Port-wine. 

^Madeira 

-Marsala 

Swedish  punch 

Brandy 

French  cognac 

Liqueurs 


06 

20. 


863 
776  1 
801 
808 
795 
774  1 
791  ' 
790  1 
479  I 


94 

23 

115 

23 

90 

134 

94 

105 

120 

72 

.170 

35 

164 

62 

156 

53 

164 

46 

263 

460 

650 

442-590 

6 
4 

115 
87 
51 
15 
40 
33 
35 

332 


260-475 


1i 


5.9 
5.0 
6.0 
6.0 
7.0 
5.0 
4.0 
5.0 
5.0 


e 

' 

c 

b 

— 

< 

£t 

0 

2.0 

2.0 

1.0 

1.0 

1.0 

2.0 

9.0 

3.0 

6.0 

5.0 

2.0 

3.0 

3.0 

3.0 

4.0 

4.0 

(60-70 


596  INDEX  TO  SPECTRUM  PLATE, 


SPECTKUM  PLATE. 

1.  Absorption  spectrum  of  a  solution  of  oxyhcumoglohin. 

2.  AbsorptioQ  spectrum  of  a  solution  of  hemoglobin,  obtained  by  the  action  of  an 

ammoaiacal  ferro- tartrate  solution  on  an  oxyhgemoglobiu  solution. 

3.  Absorption  spectrum  of  a  faintly-alkaline  solution  of  methmmogiohin. 

4.  Absorption  spectrum  of  a  solution  of  hosmatin  in  ether  containing  oxalic  acid. 

5.  Absorption  spectrum  of  an  alkaline  solution  of  Timmatin. 

6.  Absorption  spectrum  of  an  alkaline  solution  of  hmmochromogen,  obtstffred  by  the 

action    of  an    ammoniacal    ferro-tartrate    solution    on    an    alkaline-hsematin 
solutiou. 

7.  Absorption  spectrum  of  an  acid  solution  of  urobilin. 

8.  Absorption  spectrum  of  an  alkaline  solution  of  urobilin  after  the  addition  of  a 

zinc  chloride  solutiou. 

9.  Absorption  spectrum  of  a  solution  of  lutein  (ethereal  extract  of  the  egg-yolk). 


INDEX. 


Absorption,  304 — 315 

,  action  of  putrefactive  processes 
in  the  intestine  on,  298,  299 
Absorption  ratio,  153 

of    the    blood    pigments, 
154 
Acetanilid.  behavior  in  animal  body,  479 
Acetic  acid  in  intestinal  contents,  293 
in  gastric  juice,  2G0 
in   gastric   contents,   2G0,   275, 
279 
,  passage  of.  into  urine.  459,  470 
Aceto-acetic  acid.     See  Diacetic  acid. 
Acetone,  508 

in   blood,    108 
in  urine,  50G,  508 
Acetonuria,  500,  508 
Aeetophenon,  behavior  in  body,  482 
Acetylene,  compound  with  haemoglobin,  147 
Acetyl  equivalent,  97 
Acetyl  acid  equivalent.  97 
Acetyl-amido  benzoic  acid,  481 
Acholia,  pigmentary,  240 
Achromatin,  100 
Achroo-dextrin.  89.  253 
Acid  albuminates,  10 

,  properties,  31 — 33 
,  formation   in   peptic   di- 
gestion, 205,  200 
.  absorption  of,  304 
Acid  amides,  behavior  in  the  animal  bodv, 

470 
Aciil  equivalent.  97 
Acid  fermentation  of  urine.  513 
Acid  rigor.  340 
Acids,    organic,    behavior    in    the    animal 

bo<ly.  408.  4.59.  470 
Acidity  of  urine,  407.  408,  408 

of  the  gastric  contents.  270 
of  the  muscles.  332.  340 
Acrite.  79 
Acrolein,  93 
Acrolein  test,  93,  90 
Acroses.  79 

Acrylic  acid  diureid.     See  Uric  acid. 
Actiniochrom.  520 
Adamkiewicz's  reaction,  27 
Adelomorphic  cells,  257 


Adenin,  115 

,  properties,     reaction,     and     occur- 
rence, 119 
in  urine,  435 
Adenylic  acid,  109 
Adhesion,  importance  in  blood  coagulation, 

102,  103 
Adipocere,  327 
-Egagropila,  303 
.^-^rotonometric  method,  541 
Age,  influence  on  metabolism,  579,  580 
Alanin,  GO 
Albamin,  22 
Albumins,  10 

,  general  properties,  30 
.  See  also  the  various  albumins. 
Albumin,  detection  of,  in  urine,  484,  485 

,  quantitative  estimation  in  urine 

488 
.  See  Proteids. 
Albuminates,  10 

,  properties       and       reactions, 

31—33 
,  ferruginous  albuminate  in  the 
spleen,  199 
Albuminoids,  IG,  51 

in  cartilage.  317.  320 
in  the  lens  fibres.  307 
Albumoids,  IG.  51 

in  tracheal  cartilage,  52 
in  lens  fibres,  307 
Albuminose.  in  spermatozoa.  372 
Albuminous  bodies.     See  Proteids. 
Albuminous  glands,  249 
Albumoses,  10 

,  general  properties,  .33 — 42 

,  production    in    putrefaction   of 

proteids,  294 
,  formation   in   peptic   digestion, 

205 
,  formation  in  trvptie  digestion. 

289 
,  relationship   to   coagulation   of 

blood,  leO,   107 
,  nutritive  value.  571.  572 
,  absorption  of,  304 — 300 
,  transformation     of.    into    pro- 
teid,  300 

597 


598 


INDEX. 


Albumoses,  occun-ence  in  urine,  487 
Alcapton  and  alcaptonuria,  446,  451,  452 
Alcohol.     See  Ethyl  alcohol. 
Alcohols,  behavior  in  animal  body,  477 
Alcoholic  fermentation,  10,  76 

in  intestine,  294 
in  milk,  392 
Aldehydes,  behavior   in  the  animal  body, 

477 
Alturon  grains,  376 
Aloxines,  14,  181 
Aldoses,  72,  74 

Alimentary  glycosuria,  220,  308 
Alizarin  in  the  urine,  483 
Alizarin  blue,  behavior  in  the  tissues,  5 
Alkali  albuminates,  16 

,  properties     and     reac- 
tions, 31—33 
,  occurrence   in  the   egg 

yolk,  377 
J  occurrence        in        the 

brain,  358 
,  occuiTence    in    smooth 

muscles,  356 
,  absorption  of,  303 
,  Lieberkiihn's  alkali  al- 
buminate, 32 
Alkali     carbonates,     physiological     impor- 
tance, 565 
,  importance     for     gas- 
eous exchange, 
532—534 
,  action  on  secretion  of 
gastric  juice,  259 
,                              ,  action  on  secretion  of 
pancreatic  juice,  283 
.  See      various      tissues 
and  fluids. 
Alkalies,  relation  to  gaseous  exchange,  160 
,  diffusible    and    non-diffusible    in 

blood,  135,  158 
,  division    of,    in    blood    corpuscles 

and  plasma,  158,  170 
.  See   also   the   various   fluids   and 
tissues. 
Alkali  phosphates  in  urine,  407,  408,  432, 
466 
,  occurrence.       See       the 
various    fluids    and 
organs. 
Alkali  urates,  408.  432 

in  calculi,  517,  518 
in  sediments,  408,  432,  514, 
515 
Alkaline  earths,  elimination  bv  the  intes- 
tine, 466,  "467,  472 
in  urine,  483 
in  bones,  321,  .322 
,  insuflifient  supply  of,  324 
Alkaline  fermentation  of  urine.  .514 
Alkaloids,  action  on  muscles,  346 

,  passage  of,  into  urine,  483 
,  retention  by  the  liver,  206 


Allantoic  fluid,  384 

Allantoin,  properties  and  occurrence,  439, 
440 
in  transudations,  193,  384 
,  formation   from    uric   acid,   426, 
439 
Alloxan,  426,  433 
AUoxuric  bases,   113,  435 
AUoxuric  bodies,  114,  429 
Alkylsulphide  in  the  skunk,  527 
Almen-Bottger-Nylander's    sugar    test,    81, 

497 
Amanitin,  103 
Ambergris,  304 
Ambrain,  304 

Amido  acids,  relation  to  formation  of  uric 
acid,  429 
,  relation  to  formation  of  urea, 

412,  476 
,  formation     in     putrefaction, 

20,   294 
,  formation  from   protein  sub- 
stances,   15,    17—21,    62 — 
68,  294 
,  formation    in    tryptic    diges- 
tion, 289 
Amido-acetic  acid.     See  GlycocoU. 
Amido-benzoic  acids,  behavior  in  the  ani- 
mal body,  480 
Amido-caproic  acid.     See  Leucin. 
Amido-cinnamic  acid,  478 
Amido-ethylen-lactic  acid.     See~^rin. 
Amido-oxyethyl      sulphonic      acid.         See 

Taurin. 
Amido-phenyl-acetic  acid,  behavior  in  ani- 
mal body,  479 
Amido-phenyl  propionic  acid,  formation  in 

the  putrefaction  of  proteids,  20,  441 
Amido-phenyl   propionic   acid,   behavior  in 

the  animal  body,  478,  479 
Amido    pyrotartaric    acid.      See    Glutamic 

acid. 
Amido-succinic  acid.     See  Aspartic  acid. 
Amido  thiolactic  acid,  behavior  in  the  ani- 
mal body,  477 
Amidulin,  *87,  253 
6-umino-2-oxypurin,  118 
Ammonia,   formation   in   proteid   putrefac- 
tion, 294 
,  formation     from     protein     sub- 
stances, 18,   19,  289,  294 
,  formation   in   tryptic   digestion, 

289 
,  occurrence    in    blood,    172,    413, 

470,  471 
,  occurrence    in    urine,    408,    414, 

415,  428,  429,  471 
,  elimination  after  administration 

of  mineral  acids,  408,  471 
,  elimination    in    diseases    of    the 

livor.  411,  415 
,  after  extirpation  or  atrophy  of 
the  liver,  415 


INDEX. 


599 


Ammonia,  estimation  of,  in  urine,  472 
Ammonium  chloride,  action  on  metabolism, 

577 
Ammonium  salts,  relation  to  formation  of 
glj'cogen,  214 
,  relation  to  formation  of 

urea,  412 — 114 
,  relation  to  formation  of 

uric  acid,  428 
,  relation  to  permeability 
of   the    blood    corpus- 
cles,  IGO 
Ammonium-magnesium   phosphate   in    uri- 
nary calculi,  51(j — 518 
Anmionium-magnesium    phosphate    in    uri- 
nary sediment.  514 — 510 
Ammonium  sulphate,  method  of  separating 
albumoses,   37,  41 
,  method  of  separating 
carbohydrates,    38, 
89,  212' 
Ammonium    urate    in    urinary    sediments, 
514,  515 
in  urinary  calculi,  517 
Amniotic  fluid,  384 
Amphicreatin,  341 
Amphopeptone,  35 
Amyl  nitrate,  poisoning  with,  180 
Amvlndextrin.  87 
Amyloid,  16,  48,  318 

,  vegetable,  90 
Amyloid  degeneration,  bile  in,  241 

,  chondroitin    -    sul- 
phuric    acid     in 
the  liver  in,  318 
Amylolytic  enzymes,  12,  252,  285 
Amylopsin,  285 
Amylum.     See  Starch. 
Ana'raia,  pernicious,   177 
Anhvdride   theory   of  glycogen   formation, 

2 1 .") 
Aniiin,  behavior  in  the  animal  body,  479 
Anisotropous  substance,  332 
Antedonin,  526 
Anthrax  protein.  17 
Antialbumate,  265 
Antialbumid,  265 
Antialbumose,  37 
Antifehrin,    relation     to     elimination     of 

urobilin.  456 
Antimony,  passage  of,  into  milk,  404 

,  action    on    the    elimination    of 
nitrogen.  411 
An ti peptone,  35—38,  43 
AntipjTin,    relation    to    formation    of   gly- 
cogen. 214 
,  action  on  the  urine,  456,  483 
,  relation  to  the  permeability  of 
the  blood  corpuscles,  160 
Antitoxins,  14 
Apatite  in  bone  earth,  322 
Approximate     estimation     of     proteid     in 
urine,  488 


Arabinose,  78,  91 

,  relation    to    formation    of    gly- 
cogen, 78,  214 
Arabit,  73 

Arachidic  acid  in  butter,  388 
Arachnoidal  fluid,  189 
Arbacia,  372 
Arbacin,  02,  372 

Arbutin,  relation  to  formation  of  glycogen, 
214 
,  behavior  in  the  animal  body,  447 
Arginin,  19,  24,  .52,  54,  59,  69,  289 
Argon  in  blood,  530 
Aromatic  compounds,  behavior  in  animal 

body,  478—483 
Aromatic  oxyacids,  450 — 453 
Arsenic,  passage  of,  into  milk,  404 
in  sweat,  529 

action     on     the     elimination     of 
nitrogen,  411 
Arsenious  acid,  action  on  peptic  digestion, 

205 
Arseniuretted    hydrogen,    poisoning    with, 

242,  244,  490 
Arterin,  138 
Ascitic  fluids,  192 
Asparagin,  67 

.,  relation    to    synthe.sis    of    pro- 

teids,  24 
,  relation    to    formation    of    gly- 
cogen, 214 
,  nutritive  value,  572 
Asparaginic  acid.     See  Aspartic  acid. 
Aspartic  acid,  67 

,  relation     to     formation     of 

uric  acid,  429 
,  relation     to     formation     of 

urea,  412 
,  formation   from   proteid,   20, 

07 
.  behavior    in    the    organism, 
412,  429,  476 
Asparagus,    odoriferous   bodies   of,    in    the 

urine.  483 
Assimilation  limit.  220,  309 
Ass's  milk,  396,  .397 
Atniidalbumin,  36 
Atmidalbumose,  36 

Atropin,  action  of,  elimination  of  uric  acid, 
428 
,  on  the  secretion  of  saliva,  256 
Auto-digestion  of  the  stomach,  275 
Auto-intoxication.  14 
Auto-oxidizabie  bodies,  3 
Auto-oxidation,  3,  6 

Bacteria  urete,  514 
Bactericidal   action.   14,   181 
Banting  cure,  590,  591 

Barium   salts,   behavior  to  blood   coagula- 
tion. 124 
Bases,  nitrogenous,  from  proteids,  68 — 70 
in  the  thyroidea,  202 


600 


INDEX. 


Beeswax,  98 

Bela's  acetone  reaction,  509 

Benzaldehyde,  oxidation  of,  4 

,  substituted     aldehyde,     be- 
havior    in     the     animal 
body,  480 
Benzoic  acid,  formation  from  protein  sub- 
stances, 22,  55,  441 
,  passage  of,  into  sweat,  528 
,  behavior    in    the    organism, 

68,  441,  480 
,  occurrence  in  the  urine,  441, 

443 
,  substituted     benzoic     acids, 
action  in  body,  480 
Benzol,  behavior  in  the  animal  body,  478, 

479 
Benzoyl-amido-acetic    acid.      See   Hippuric 

acid. 
Benzoyl-chloride,     behavior     to     carbohy- 
drates, 82,  212,  500 
,  behavior  to  cystin,  512 
Benzoyl-cystin,  512 
Benzoar-stones,  30.3 
Bifurcated  air,  540 
Bile,  223—249 

,  general  chemical  properties,  225 
,  analysis  of,  239 
,  antiseptic  action,  298,  299 
,  constituents  of,  22G,  237 

in  disease,  240 
,  diastatic  action,  237,  291 
,  influence  on  proteid  digestion,  292 
,  on  the  emulsification  of  fats,  292,  314 
,  on  the  secretion  of,  225 
,  on   the   absorption   of   fat,   298,   311, 

314 
,  cleavage  of  neutral  fats,  292,  314 
,  on  tryptic  digestion,  289,  293 
,  quantity  of.  224 

,  solvent  "^f or  fatty  acids,  291,  292,  311 
,  passage  of  foreign  bodies,  240 
,  occurrence    of,    in    urine,    314,    315, 

494—496 
,  occurrence  of,  in  gastric  contents,  276, 
292 
in  meconium,  302 
,  composition  of,  238,  240 
,  formation   of,  241 — 245 
,  secretion  of,  224,  225 
Bile-concretions,  245 
Bile-pigments,  23.3—2.37 

,  origin  and  formation,  242 — 

245 
,  reactions,  235,  236,  494,  495 
,  passage  of,  into  urine,  494, 

495 
,  occurrence    in    blood-serum, 

1.34,  180 
,  occvirrcnce  in  egg-shells,  382 
Biliary  fistulse,  223 

,  influence   of,   on   intestinal 
putrefaction,  299 


Biliary   fistulse,  influence  on  the  want  of 

food,  299 
Bile-salts,  226 
Bile-acids,  227—231 

in  blood,  180,  241 
in  pus,  198 
in  urine,  315,  494 
,  absorption  of,  315 
Bile-mucus,  225 
Bilianic  acid,  229 
Bilicyanin,  233,  235,  237,  495 
Bilifulvin,  237 
Bilifuscin,  233,  237,  245 
Bilihumin,  233,  237 
Bilipha2in,  233 
Biliprasin,  233,  237 
Bilirubin,  233,  234 

,  relationship    to    blood-pigments, 

152,  243 
,  relationship  to  haematoidin,  152,. 

233,  243 
,  relationship  to  proteinchrom,  289 
,  properties,  234 
,  occurrence,  233 

,  occurrence  in  corpora  lutea,  373 
,  occurrence  in  urine,  494 
,  occurrence  in  the  placenta,  383 
Biliverdin,  236 

in  the  egg-shell,  382 
in  faeces,  302 
in  urine,  394 
in  the  placenta,  383~^-^ 
Biliverdinic  acid,  236 
Bismuth,  passage  of,  into  milk,  404 
Birotation,  76 
Bitch's  milk,  397,  401 
Biuret,  416 

Biuret,  reaction,  27,  416 
Blister  fluid,  195 
Blonds,  milk  of,  400 
Blood,  123—183 

,  general  behavior,  123,  157 — 161 
,  analyses,  quantitative,  168 — 172 
,  arterial  and  venous,  138,  172,  531 
,  defibrinated,  124 
,  asphyxiation,  5,  138,  161,  531 
,  quantity  of,  in  the  body,  180 
,  detection,  chemico-legal,  152 
,  behavior  in  starvation,  175,  176,  561 
,  composition    under    A^arious    condi- 
tions, 172—180 
in  gastric  contents,  276 
in  urine,  490—492 
Blood  analysis,  methodical,  153,   168,   169, 

170 
Blood-casts,  491 
Blood-clot,  124,  160 
Blood-corpuscles,  white,  155,  156,  178 

,  relation    to    coagulation, 

1.56,  162—166 
,  relation   to   formation   of 

uric  acid,  430 
,  red,  136—138 


INDEX. 


601 


Blood-oorpuscles,  number  of,  137,  176 

,  relation      to     high     alti- 
tudes, 17tJ 
,  passage     of,     into    urine, 

4U0.  41U 
j'pernieahility,   159 
,  composition,      154,      155, 
171.   177,   178 
BlooJ-pigments,  138 — 154 

in  bile,  241 
in  urine,  490—493 
Blood-plasma,  125 — 132 

,  composition  of,  135,   171 
Blood-plates,  155,  15G 

,  relation     to     coagulation     of 
blooil.  102 
Blood-scrum,  124,  132— 13G 

,  globulicidal  action  of,  181 
,  action  of  enzymes  in,  133,  134, 

181 
,  composition  of,  135,  171 
Blood-spots,  152 
Blood-sweat,  529  * 

Blue  stentorin,  526 
Bones  and  bone  tissues,  321 — 326 

in    starvation,    467, 
560 
Bone-earths,  321,  322 
Bones,  softening  of,  324 
Boncllin,  526 
Borax,  action  on  metabolism,  577 

,  on  tryptic  digestion,  289 
Borneol,  482  ' 

Biittcher's  spermin  crystals.  370 
Bottger-Almcn's  sugar  test,  81,  497 
Bowman's  disks,  333 
Brain,  358—364 
Bread,  behavior  in  the  stomach,  270 

,  action  of,  on   the  secretion  of  gas- 
tric juice,  259 
,  action  of,  on  the  secretion  of  pan- 
creatic juice,  284 
,  excrement,  after  feeding  with,  300, 
307 
Bromadenin.  116 
Bromanil.  22 
Bromhypoxanthin,  116 
Bromides.  l)ehavior  to  secretion  of  gastric 

juice.  268 
Bromine,  action  on  proteids,  23 

,  action  on  pri)teiiuhro"i,  289 
,  passage  of,  into  saliva,  256 
Bromoform,  22 

,  behavior  in  the  animal  body, 
477 
Brunettes,  milk  of.  400 
Brunner's  glands.  279 
Buccal  mucus.  251 
Buffy  coat.  161 
Bufidin.  527 
Bull,  spermatozoa.  372 
Bursa?  mucosae,  contents  of,  196 
Butalanin,  66 


Butter-fat,  388,  397 

,  calorific  value,  554 
,  absorption   of,  312 
Butterfly,  pigment  of  wings,  427,  525 
Buttermilk,  396 
Butyl     alcohol,    behavior    in     the    animal 

body,  477 
Butyl-chloral  hydrate,  behavior  in  the  ani- 
mal body.  477 
Butyric  acid  in  gastric  contents,  275,  279 
in  gastric  juice.  260 
in  milk  fat,  388.  397 
Butyric-acid  fermentation,  4,  5,  386 

in  intestine,  296 
Byssus,  16,  58 

Cachexia  thyreopriva,  202 
Cadaverin,  13 

in  intestine,  512 
in  urine,  463,  512 
Caffein,  115 

,  behavior  in  the  animal  body,  430 
,  action  on  the  muscles,  .346 
Calcium,  lack  of,  in  food,  324,  325 

,  occurrence.      See    various    tissues 
and  Huids. 
Calcium  carbonate  in  urine,  406,  515 

in  urinary  calculi.  518 
in     urinary     sediments, 

515 
in  bones,  322,  324,  325 
in  tart    ,  257 
Calcium  casein,  389 
Calcium  formate,  enzymotic  decomposition, 

10 
Calcium  oxalate  in  urine,  438 

in  urinary  sediments.  515 
in  urinary  calculi,  517 
Calcium  phosphate,  relation  to  the  coagu- 
lation of  the  blood, 
165 
,  occurrence      in      intes- 
tinal       concretions, 
303 
in  the  urine.  406.  466. 

467.  468.  472 
in    urinary    sediments, 

515 
in   urinary   calculi.  518 
in      salivary      calculi, 
257 
Calcium  salts,  elimination,  466,  467.  472 

,  impoTtance    to    coagulation 
o;    the    blood,    124.    128. 
164.  165 
,  relation   to   the   coagulation 

of  the  milk.  390 
,  importance    to    coagulation 

of  milk,  389.  .390 
.     See  various  calcium  salts. 
Calcium  sulphate  in  urinary  sediments.  515 
Calculi,  salivary.  2.)7 

,  intestinal,  303,  304 


602 


INDEX. 


Calculi,  urinary,  516 — 519 
Calories  of  food  stufl's,  554 — 556 

of  different  rations,  585 — 590 
Campho-glj'curonic  acid,  460,  482 
Camphor,    behavior    in    the    animal    body, 

460,  482 
Camphoral,  482 
Cane-sugar,  84,  85 

,  inversion  of,  216,  266,  291,  308 

,  calorific  value  of,  554 

,  absorption  of,  308 

,  behavior  with  intestinal  juice, 

280 
,  behavior    with    gastric    juice, 
266 
Capillary     endothelium,     secretory     impor- 
tance, 188,  189 
Capranica's  reaction  for  guanin,  118 
Capric  acid,  92,  388.  397 
Caproic  acid,  92,  388,  397 
Caprylic  acid,  92,  388 
Caramel,  80,  85 
Carbamic  acid,  422 

in  blood,  134,  413 
in  urine,  413,  422 
,  poisonous  action,  413 
Carbamic-acid  ethylester,  422 
Carbazol,  behavior  in  body,  479 
Carbohaemoglobin,   146 
Carbohydrates,  71—92 

,   importance   in   fat   fomia- 

tion,  330 
,  importance      in      glycogen 

formation,  214,  216 
,  importance     for     muscular 
activity,  348,  349,  352— 
354 
,  action   on   proteid  metabo- 
lism, 565,  566,  573—576 
,  action  on  intestinal  putre- 
faction, 298,  300,  444 
,  formation    from    fats,    218, 

220 
,  absorption  of,  308—311 
,  inadequate   supply   of,   566 
See  also  the  various  car- 
bohydrates. . 
Cai'bolic   acid,  action  on   peptic  digestion, 
265 
.    See  also  Phenol. 
Carbolic  urine,  447 

Carbon,  relation  to  nitrogen  in  the  urine, 
.550,  .551 
,  calorific  value,  553 
Carbon  dioxide  in  the  blood,  531 — 535,  541 — 
543 
in    the    blood    in    diabetes, 

535 
in    the   blood    in    poisoning 
Avith  mineral  acids,  535 
in  the  intestine.  294.  296 
in  the  lymph,  184,  535 
in  the  stomach,  271 


Carbon  dioxide  in  the  muscles  during  rest 
and  activity,  348,  352 
in    the    muscles     in     rigor 

mortis,  346 
in  the  secretions,  535 
in  transudations,  536 
,  binding     of     CO,     in     the 

blood,  532—535 
,  action  on  the  secretion  of 

gastric  juice,  258 
,  tension    of,    in    the    blood, 

541,  542 
,  tension   of,    in    the    tissues, 

543 
,  tension  of,  in  lymph,  184 
,  tension     of,     in     transuda- 
tions, 536 
elimination,    dependence    of 
external       temperature 
upon,  583 
elimination     in     rest     and 
activity,  348,  352,  581, 
'  582 
elimination     by     the    skin, 

529 
elimination  in  various  ages, 

579,  580 
haemoglobin,  146 
Carbon-monoxide  poisoning,  145,  221,  343 
Carbon-monoxide  poisoning,  action  on  the 

formation  of  lactic  acid,  343 
Carbon-monoxide  poisoning,  action,  on  the 

elimination  of  niti'ogen,  411 
Carbon-monoxide  poisoning,  action  on  the 

elimination  of  sugar,  221,  343 
Carbon-monoxide    hsemoglobin,  145,  146,  147 
Carbon-monoxide  methsemoglobin,  146 
Carbon-monoxide    blood    test,    Hoppe-Sey- 

ler's,  146 
Carcinoma,   lactic    acid    in   stomach    with, 

276 
Carminic  acid,  525 
Carnic  acid,  35,  43,  340 
Carniferrin,  44,  340 
Carnin,  115,  340 

in  urine,  435 
Carp,  sperma  of,  372 
Cartilage,  317—321 

,  quantity  of  ash,  320 

,  behavior   to   gastric   juice,    266, 

270 
,  heliavior  to  pancreatic  juice,  290 
Cartilage  gelatin,  57 
Casein,  origin,  403 

,  from  woman's  milk,  398 

,  from  cow's  milk,  388,  389 

,  quantitative     estimation     of,     393, 

.394 
,  absorption  of,  304 
,  behavior  towards  rennin,  267,  389, 

390,  398 
,  behavior  to  gastric  juice,  265,  270, 
390,  398 


INDEX. 


603 


Casein,  heat  of  combustion,  554 
Caseinogen.  3'JO 
Caseoses,  3(j 

,  relation  to  the  coagulation  of  the 
blood,  124 
Castor  bean,  14 
Castoreuni,  52U 
Castorin,  520 
Cataract.  ;J(i8 

Catheterization  of  the  lungs,  539,  541 
Cats  milk,  3!)(i.  397 
Cell,  animal.  99—123 
Cell  constituents,  primary  and  secondaiy, 

100 
Cell  fibrinogen.  112 
Cell  globulins.  100,  137 
Cell  membrane.  102 
Cell  nucleus,  lOG 

,  relation     to     coagulation     ot 
fibrinogen,  157,  162 
Cellulose.  90 

,  fermentation  of,  291,  297 
,  occurrence  in  tuberculosis,  545 
.  action    on    absorption    of    food- 
stuffs, 307 
Cement,  325 

Cerebellum,  composition  of,  363 
Cerebrin,  84,  197.  359,  361 

,  properties  and  behavior,  361,  362 
in  pus,  199 
Cerebrosides.  197,  360,  361 
Cerebrospinal  fluid,  194 
Cerolein.  98 
Cerotic  acid,  98 
Cerumen,  526 
Cetin,  98 
Cetyl  alcohol,  98 
Chalaza,  378 

Charcot's  crystals,  178,  371 
Chcno-taurocholic  acid,  229 
Childrcus  urine.  406,  410,  439 
Chitin,  .58.  .521,  522 

,  behavior  in  tryptic  digestion,  290 
Chitosamin.  40.  75,  523 
Chloral    hydrate,    behavior   in    the   animal 

body,  460.  477 
Chlorates,  poisoning  with,  180,  490 
Chlorazol,  22 
Chlorbenzol.  behavior  in  the  animal  body, 

482 
Chlorides,   elimination   by   the   urine.    136, 
463,  464 
,  elimination  by  the  sweat,  528 
,  action    on    proteid    metabolism, 

577 
,  insufficient  supply  of,  564 
.  See     also     various     fluids     and 
tissues. 
Chlorocruorin,  154 

Chloroform,   action   on   the  elimination  of 
chlorides.  464 
,  .action  on  the  muscles.  .346 
,  behavior  in  the  animal  body,477 


Chlorophan,  366 
Chlorophyll,  2,  526 

,  relation    to    blood    pigments, 
139 
Chloroproteinchrom,   290 
Chlorosis,  177 
Chlorphenylcystein,  483 
Chlorphenylmerca])turic  acid,  483 
Chlorrhodinic  acid.    198 
Cholagogues,  224,  225 
Cholalic  acid,  229 

,  relation  to  cholesterin,  246 
Cholanic  acid,  230 
Cholecyanin,  235,  236 
Choleic  acid,  230 
Cholepvrrhin,  233 
Cholera,  blood  in,  178,  179 
,  sweat  in,  128 
,  ptomaines  in,  13 
Cholera  bacilli,  behavior  with  gastric  juice, 

274 
Cholesterilene,  246 
Cholestcrilin,  246 
Cholesterin,  246 

in  blood  serum,  1.32 
in  sputum.  545 
in  the  bile.  226.  237.  239,  240 
in  the  brain,  359,  364 
in  the  urine,  511 
,  importance    in    the    life    proc- 
esses of  the  cell,  100,  106 
Cholesterin  calculi,  245,  519 
Cholesterin  fat,  as  protective  fat,  526 
Cholesterin-propionie  ester,  247 
Cholesterinic  acid,  229 
Cholesteron.  246 
Choletelin,  233,  236 

,  relation  to  urobilin,  454 
Cholic  acid.     See  Cholalic  acid. 
Cholin,   14.   103.  237 
Choloha^matin.  237 
Choloidic  acid,  231 
Clolylic  acid.  229 
Chondrigen.  317 
Chondrin,  57,  317 

in  pus.  198 
Chondrin  balls,  320 
Chondroitic  acid,  318 
Chondroitin,  318 

Chondroitin-sulphuric    acid,    48,    317,    318, 

319 
in   urine,  461, 

489 
in       kidneys, 
406 
Chondrormucoid,  48,  317,  319 
Chondroproteids,  44.  48 

in  the  urine,  461.  489 
Chondrosin     from     chondroitin  -  sulphuric 
acid,   318 
from  sponges,  48 
Chorda  saliva,  250 
i   Choroid  coat,  368 


604 


INDEX. 


Choroid  coat,  pigment  of,  524 
Lliristenseu   and   Mygge's  approximate  es- 
timation of  proteid  in  urine,  489 
Chromatin,    106 
C  hromhidrosis,  529 
Chromogens  in  urine,  453 

in  supra-renal  capsule,  204 
Chrysophanic  acid,  action  on  urine,  483 
Chyle,   183—185 
Chylopericardium,   191 
Chyluria,  511 
Chyme,  270 

,  investigation  of,  276 — 279 
Chymosin,  12,  267,  389,  390 
in  urine,  462 
.  See  also  rennin. 
Cilianic  acid,  229 

Cinnamic  acid,  behavior  in  the  bodv,  441 
Citric  acid  in  milk,  388,  395,  399 
Clupein,  59,  60 
Coagulated  proteids,  16,  42 
Coagulation    of   the   blood,    123,    124,    128, 
129,  160—166,  178 
,  intravascular,  166 
of   milk,   386.   387,   389,   390, 

398 
of  muscle  plasma,   333,   336, 
346 
Coecinic  acid,  525 
Cochineal,  525 
Cochinillic  acid,  525 
Coefficient,  Haser's,  474 

,  respiratory,  330,  352,  552,  559, 

582 
,  extinction,  153,  154 
,  urotoxic,   463 
Coffee,  action  on  metabolism,  578 
Collagen,  16,  54,  316,  317,  319,  321 
Collidin,   13 
Colloid,  47,  373,  374 
Colloid  corpuscles,  373 
Colloid  cysts,  373 

Coloring  matters.     See  various  pigments. 
Colostrum  of  woman's  milk,  400 

of  cow's  milk,  395,  396 
Colo.strum  corpuscles,  395 
Comma    bacillus,    behavior    with    gastric 

juice,  274 
Compound  proteids,  16,  44 — 51 

.  See        the        different 
groups    of   protein 
substances. 
Conchiolin,  16,  .58 
Concrements.     See  various  calculi. 
Cones  of  the  retina,  pigment  of,  366 
Conglutin,  calorific  value  of,  554 
Conifer  seeds,  proteifl  of,  69 
Connective  tissues,  316 
Contact  action,  12 

Copaiva  balsam,  action  on  the  urine,  483 
Copper  in  blood,  1.34,  170 
in  bile.  23S 
in  biliary  calculi,  245 


Copper  in  hsemocyanin,  154 

in  protein  substances,  15 
in  turacin,  525 
Cornea,  320,  368 
Cornein,  16,  58 
Cornicrystallin,  58 
Corpora  lutea,  373,  377 
Corpulence,  diet  cures  for,  590,  591 
Corpuscula  amvlacea,  363 
Cor^v's  milk,  385—397 

,  general  behavior,  385,  SSG 
,  analysis  of,  393—395 
,  inorganic  constituents  of,  395 
,  organic  constituents  of.  388 — 

393 
,  anti-jDutrefactive      action      of, 

298—444 
,  coagulation  with  rennin,  267, 

386.  398 
,  behavior  in  the  stomach,  270, 

274 
,  composition  of,  395 
Cream,  396 

Creatin,  relation  to  formation  of  urea,  339, 
410 
,  relation  to  muscular  activitv,  350, 

352 
,  properties     and     occurrence,     338, 
339 
Creatinin,    relation    to    muscular    activity, 
350,  352,  423 
,  properties  and  occair^ence,422,423 
,  zinc  chloride,  423 
Cresol,  20,  294,  443,  444 
Cresol-sulphuric  acid,  443,  444 
Crotonic  acid,  511 
Cruor,  124 
Crusocreatinin,  341 
Crustaceorubin,  526 
Crusta   inflammatoria   or  phlogistica,    161, 

178 
Crystalbumin,  368 
Crystalfibrin,  368 
Ci-ystallins,  16.  367,  368 
Crystalline  lens,  367,  368 
Crystalline  seralbumin,  132 
Cumic  acid,  480 
Cuminuric  acid,  480 

Curare  poisoning,  action  on  muscular  tonus, 
.347 
,  action  on  elimination  of 
sugar,  221 
Curd,  390 
Cyanhydrines.  73 
Cj'anmethsemoglobin,  147 
Cyanoerystallin,  382,  525 
Cyanogen  in  proteid  molecule,  4 
Cyanuric  acid,  416,  426 
Cyanurin.  453 
Cymol.  479 
Cystein.  483.  512 

,  conjugation  in  animal  body,  483 
Cystin,  52,  ois 


INJJh'X. 


605 


Cystin,  pioportios,  512 

,  (H'ouneiioe  in  urine,  461,  462,  512 
,  ocriinenee    in    urinary    sediuienls, 

51(5 
,  octurrcnco -in  urinary  calculi,  518 
,  occurrence  in  sweat,  529 
Cystinuria,  13,  4(i2,  512 
Cysts,  ta|ic\\<)riii,   l'J5 
,  ovarial,  ."JTS — 376 
,  thyroid,  204 
Cytin.  52;  112 

Cylofilol.in.   10,  101,  112,  1G3 
Cytosin,    110 

Dauialuric  acid.  463 

Damolic  acid,  403 

Dctil)rinatod   blood,   124 

Delivdroi-liolalic  acid,  229 

Doliydrocliolcic  acid,  230 

Dcliiinorpliic  or  parietal  cells,  257 

]>iii<rcs  reaction  for  uric  acid,  433 

Dentin.  322,  325 

Dermoid  cyst,  fat  from,  98 

Desaniidoalhuminic  acid,  33 

Desccniet's   membrane,  48,  321 

Desoxydiolaiic  acid,  229,  230 

Deuteroalbumose,  30,  38,  487 

Deuteropclatose,  57 

Devoto's  method  of  estimating  proteids,  487 

Dextrins,  89 

,  formation   from   starch,   89,   253, 

285 
,  loading  the  stomach  with,  209 
,  occurrence    in    the    gastric    con- 
tents, 271 
,  occurrence  in  muscles,  342 
,  occurrence  in  portal  blood,   173, 
308 
Dextrin-like  substance  in  the  urine,  459 
Dextrose,  79 — 83 

in  blood,  132,  173,  218,  219—223 
in  urine,  179,  219,  220,  459,  496, 

505 
in  the  lympli,  183 
in  muscles,  342 
,  preparation  of,  82 
,  calorific  value  of,  554 
,  detection,  82,  497-  500 
.  reactions  of,  80—82 
,  absorption  of.  3n«,  309 
.  quantitative  estimation,  500 — 505 
Diabetes  mellitus,  219—223.  490 

,  elimination   of  ammonia 

by  the  urine  in,  471 
,  relationship  of  the  liver 

to,  221.  222 
,  relationship  of  the  pan- 
creas to.  221.  222,  223 
,  blood  in,  179,  221 
,  amount      of     sugar     in 
blood  in.  179,219,220 
,  urin''  in.  407 
,  CO^  in  the  blood  in,  535 


Diabetes  mcllilu>.  osyldityric  ;icid   in   the 
blood   in,  535 
,  oxybutyrie   acid    in    the 
urine  in,  471,  510 

Diacetic  acid,  509 

in  urine,  500,  507 

Diamid,  poisoning  with,  440 

Diamins  in  the  urine,  13,  403,  512 

in  the  gastric  contents,  13,  512 

Diamido-acetic  acid,   19,  09 

Dianudo-caproic  acid.     See  Lysin. 

Diamido-valerianic  acid.     See  Ornithin. 

Diarriuca,  action  on  the  blood,   170,   178 

Diastatic  enzymes,  12,  133,  217,  252,  285 

.  See  also  other  enzymes. 

Diastase  in  the  blood,  133 

Diazobenzol-sulphonic   acid,   reaction    with 
sugar,  82 

Dicalcium  casein,  389 

Dicldorpurin,   114 

Diet  cures,  590,  591 

Diet  for  various  classes  of  people,  585 — 589 

Digestion,  249—316 

Digestibility   of  food-stufTs,   272,   273,  274, 
307,  310,  312 

Digestion  leucocytosis,  178,  427 

Dimethylanilin    as    solvent    for    uric    acid, 
234 

Dimethylketone.     See  Acetone. 

Dioxyacetone,  79 

Dioxy benzol,  479 

Dioxynapiithalin,  479 

Dioxypyridin,  205 

Disaccharides,  84 

in  urine,  309,  505 
,  inversion  of,  280,  291.  308 

Distearyllecithin,    103 

Doeglic  acid,  90 

Dog's  milk,  390,  397 

Dolphin's  milk.  .397 

Donne's  pus  test,  493 

Dotterpliitchen,  24.  376 

Dropsical  tluid,  192 

Dulcite,  73 

,  relationshij)    to    formation    of  gly- 
cogen. 214 

Dysalbumose,  36 

Dyslysin,  231 

Dysoxidizable  bodies,  3 

Dyspeptone.  205 

Dyspnoea,    action    on    proteid    transforma- 
tion. 351.  411,  580 

Earthy  phosphates,  elimination  by  the 
urine.  4(50.  4(i7.  472 

,  solubility  in  fluids  rich 
in  proteid.  .325 

,  occurrence  in  bone- 
earths,  322—325 

,  occurrence  in  calculi, 
245.   303.  518 

,  occurrence  in  sedi- 
ments, 514,  51.^,516 


606 


INDEX. 


Earthy    phosphates.      See    also    different 

earthy  phosphates. 
Ebstein's  diet  cure,  590 
Echinochrom,  154 
Echinococcus  cysts,  cyst  wall,  523 

,  cyst  contents,  195 
Eck's  fistula,  413 
Eel,  flesh  of,  256 
Egg,  376 

,  hen's,  376—384 

,  absorption  in  the  intestine,  307 
,  incubation  of,  382,  383 
Egg  albumin  (see  Ovalbumin),  379 
Egg-shell,  51,  381 
Egg  yolk,  376 
Ehrlich's  test  for  bile-pigments,  496 

urine  test,  511 
Eiselt's  reaction  for  melanin,  493 
Elaidic  acid,  95 
Elaidin,   95 
Elastin  albumose,  54 
Elastinpeptone,  54 
Elastin,  16,  53 

,  behavior  with  gastric  juice,  266 
,  behavior  with  trypsin,  290 
Eleidin,  521 
Elephant  bones,  322 
milk,  397 
tusk,  326 
EUagic  acid,  304 
Emulsin,  11 
Emydin,  382 
Enamel,   325 
Encephalin,   361,  362 
Endolymph,  369 

Energy,  potential,  of  food-stuffs,  554 — 562 
Enzymes,  in  general,  9 — 12 

,  diastatic,     in     pancreatic     juice, 

284,  285 
,  diastatic,  in  blood,  133,  217 
,  diastatic,  in  bile,  237,  291 
,  diastatic,  in  urine,  462 
,  diastatic,  in  liver,  217 
,  diastatic,  in  lymph,  184 
,  diastatic,  in  muscles,  338 
,  diastatic,    in    secretion    of   intes- 
tinal mucosa,  280,  281 
,  diastatic,  in  saliva,  2.52,  2.53 
,  proteolytic,  in  intestinal  mucosa, 

281 
,  proteolytic,  in  urine,  462 
,  proteolytic,  in  stomach,  257,  260, 

261  ■ 
,  proteolytic,  in  pancreas,  284,287 
,  proteolytic,    in    plant    kingdom, 

261 
,  proteolytic,     in    lower    animals, 

261 
,  steatolytic,  12,  284 
,  coagulating.       See     Fibrin     fer- 
ment   and     Rennin     or     Chy- 
mosin. 
,  urea  forming,  in  the  liver,  412 


Enzymes,  urea  splitting,  9,  514 
Epiguanin,  115,  435,  437 
Episarkin,  115,  435,  436 
Erucic  acid,  92 

,  absorption  of,  311 
Erythrit,  relation  to  glycogen  formation,. 

214 
Erythro-dextrin,  89,  253 
Erythropsin.     See  Visual^  purple. 
Esbach's    estimation    of    proteid    in    urine, 
488 
estimation  of  urea  in  urine,  422 
Esters,  behavior  with  pancreatic  juice,  286 
Ethal,  98 
Ether,  action  on  the  blood,  137,  159 

,  action   on    the   secretion   of   gastne 

juice,  258 
,  action  on  the  muscles,  346 
Ethereal   sulphuric   acids   in  the  bile,   226, 

239 
Ethereal  sulphuric  acids  in  the  urine,  294, 

443—455,  477,  481 
Ethereal  sulphuric  acids  in  sweat,  528,  529 
Ethereal  oils,  action  on  muscles,  346 
Ethyl  alcohol,  production  in  the  intestine, 
293 
,  passage  of,  into  milk,  404 
,  behavior      in      the      animal 

body,  577 
,  action    on   the   secretion    of 

gastric  juicer-258 
,  action  on  the  muscles,  346 
,  action  on  metabolism,  577 
,  action  on  digestion,  205,  273 
EtLylamin,  solvent  for  uric  acid,  432 
Ethyl  benzol,  behavior  in  the  animal  body, 

479 
Ethylen   glycol,   relation   to   formation    of 

glycogen,  214 
Ethylenimin.     See  Spermin. 
Ethyl  idene-lactic  acid,  342.     See  also  other 

lactic  acids. 
Ethylmercaptan,   behavior    in    the    animal 

body,  477 
Ethyl-sulphuric  acid,  behavior  in  the  ani- 
mal body,  477 
Ethyl  sulphide,  formation  from  proteid,  19' 
,  behavior     in     the     animal 
body,  477 
Euxanthic  acid,  460,  482 
Euxanthin,  460,  482 
Excrements,  300—303 

in   dogs  with  biliary   fistula,. 

299 
in  starvation,  548,  .549 
Excretin,  302 
Excretolic  acid,  302 
Exostosis,  324 
Expectorations,  544,  .545 
Extinction   cnefHfioiit,   1.53,   154 
Extracellular  action  of  enzymes,  10 
Exudations,   188—196 
Eye,  364—369 


i 


INDEX. 


eo? 


FflBces.     See  Excrements. 
Fat,  origin  in  the  body,  327—331,  5G7,  568 
,  general    properties,   detection   and   oc- 
currence, 92 — yy 
,  emulsification    of,    93,    281,    287,    292, 
310—315 
in    blood    serum,    132,    134,    171,    17G, 

179 
in  chyle,  184,  185 
in  yolk  of  vgg,  'ill 
in  pus,  190,  197 
in  excrements,  302,  312,  313 
in  fatty  tissues,  326 
in  bile,  239 
in  the  brain,  359 
in  the   urin(>,  511 
in  bones.  323,  325 
in  the  liver,  208 
in  milk,  388,  397,  402,  403 
in  muscles,  relationship  to  work,  345 
in  new-bom  and  children,  326 
in  subcutaneous  connective  tissue,  208 
,  calorific  value  of,  5.54,  555 
,  nutritive  value  of,  554 — 556,  566,  572, 

576 
,  rancidity  of,  94 
,  absorption   of,  310 — 315 
,  behavior  with  tlie  intestinal  juice,  281 
,  behavior  with  gastric  juice,  2G0 
,  behavior   with    pancreatic   juice,   285, 

286,  313 
,  saponification  of,  93,  96,  97,  285,  286, 

292,    313 
,  action  of,  on  the  secretion  of  bile,  224 
,  action  of,  on  the  secretion  of  gastric 

juice,  259 
,  action    of,    on    the   secretion   of   pan- 
creatic juice,  283 
.  iodized,    behavior    of,    in    the    animal 

body,  327.  403 
,  estimation  of.  97,  98 
,  metabolism  of,  in  activity  and  at  rest, 

352,  353 
,  metabolism  of,  in  starvation,  5.59 
,  metabolism    of,    with    various    foods, 
567.  568,  572—576 
Fat-cells,  32G 
Fat-sweat,  527 

Fatty  acids,  general   properties,  detection 
and  occurrence,  91 — 96.326 
,  solubility  in  bile.  292,  311 
,  absorption  of,  310,  311 
,  synthesis     to     neutral     fats, 
310,  .327 
Fatty  degeneration,  208,  328 
Fatty  infiltration,  208 
Fatty  series,   behavior  of  members  in  the 

animal  body,  476 
Fatty  tissue, '.326 

,  behavior    with    gastric    juice, 
266,  271 
Feathers,  51,  521 

,  pigments  of,  525 


Fehling'8  solution,  81,  501 — 503 

Fellic  acid,  231 

Fermentation,  5,  9,  10,  76,  80,  81 

in  the  intestine,  293 
in  the  urine,  459,  513,  514 
in  the  gastric  contents,  27 1» 
274,  275 
.  See    also    various    fermenta- 
tions, alcoholic,  etc. 
Fermentation  lactic  acid,  properties,  occur- 
rence, etc.,  343,  344 
Fermentation  lactic  acid  in  the  brain,  359 
Fermentation    lactic    acid    in    the    gastric 

contents,  271 
Fermentation  lactic  acid  in  gastric  juice, 

2G0 
Fermentation  lactic  acid,  formation  of,  in 

the  souring  of  milk,  386 
Fermentation  lactic  acid,  detection  in  the 

gastric  contents,  277 
Fermentation  test  in  the  urine,  498,  503 
Ferments  in  general,  9,  10 

.  See  also  various  enzymes. 
Ferratin,  207 

Fevers,  elimination  of  ammonia  in,  471 
,  elimination  of  uric  acid  in,  428 
,  elimination  of  urea  in,  411 
,  elimination   of  potassium   salts   in» 

470 
,  metabolism  of  proteids  in,  411 
Fibres,  elastic,  in  sputum,  545 

,  reticulate,  316 
Fibrin,  16.  124,  126 

,  occurrence     in     transudations,     188, 

191—195 
,  Henle's,  370 
Fibrin  coagulation,  127—129,  160 — 168 
Fibrin  calculi,  303,  519 
Fibrin  digestion,  2G3,  276,  288 
Fibrin  ferment.   12,  127,   128,   163—168 
Fibrin  formation,  127—129,  160—168 
Fibrin  globulin,  128.  132 
Fibrine  soluble.     See  Serglobulin. 
Fibrinogen,  16,  125—129,  165,  166,  183,  189 
Fibrinolysis.    127 

Fibrinoplastic  substance.     See  Serglobulin^ 
Fibroin,  16,  58 
Filtration,  relation  to  absorption,  320 

,  relation    to    Ij-mph    formation, 
188 
Fischer- Weidel's  reaction,  117 
Fish-bones,  .324 
Fish-eggs.  24.  377.  382 
Fish-scales,  58,  117 
Fish,  swimming  bladder  of.  117,  543 
Flesh,  accumulation  of.  with  various  foods, 
567,  569,  572—576 
,  metabolism,  in  starvation,  .5.58 
,  metabolism,     with     various     foods, 
5G(>— 576 
Flesh  quotient.  356 
FJuorine  in  bones.  322 
in  enamel,  326 


60S 


INDEX. 


Fly-maggots,  formation  of  fat  in,  328 
Fonotion  martiale,  210 

Foods,  inlluence  on  the  secretion  of  intes- 
tinal juice,  280 
,  inHuence   on   the   secretion    of   bile, 

224,  225 
,  influence  on  the  secretion  of  gastric 

juice,  259—260 
,  influence   on   the   secretion   of   pan- 
creatic juice,  283 — 284 
,  influence  on  the  elimination  of  am- 
monia, 470,  471 
,  influence  on  the  elimination  of  uric 

acid,  427 
,  influence  on  tire  elimination  of  urea, 

442,  443 
,  influence  on  the  elimination  of  CO2, 

552,  559,  561 
,  influence  on  the  elimination  of  min- 
eral bodies,  464,  466,  469,  473 
,  influence     on     the     elimination     of 

xanthin  bodies,  434 
,  influence  on  faeces,  301,  307,  549 
,  influence      on      metabolism,      562 — 

576 
,  various,  rich  in  proteid,  566 — 569 
,  various,  mixed,  566 — 569 
,  insufficient  supply  of,  563 — 566 
Food-stuflFs,  necessity  of,  546 

,  combustion  heat  of,  554 — 556 
Formaldehyde,  formation  in  plants,  1,  79 

,  combination  with  proteid,33 

,  combination  with  urea,  417 

,  relation     to     sugar    forma- 

tion,  79 

Formanilid,  behavior  in  the  animal  body, 

(foot-note),  479 
Formic  acid  in  butter,  388 

in  gastric  contents,  279 
,  passage  of,  into  urine,  459,  476 
from  cleavage  of  nucleic  acid, 
110 
Frog's  eggs,  membrane  of,  45 
Fructosamin,  523 
Fructose.     See  Levulose. 
Fruit-sugar.     See  Levulose. 
Fundus  glands,  2.'J7,  269 
Fungi,  glycogen  therein,  211 
Fumaric  acid,  22 

Fiirbringer's  albumin  reagent,  486 
Furturacryluric  acid,  481 
Furfurol    from  giycuronic  acid,  461 
from  pentoses,  78 
,  relation  to  proteid  reactions,  28 
,  relation     to     Pettenkofer's     bile- 
acid  tests,  227 
,  reagent  for  urea,  416 
,  behavior    in    the    animal    body, 
481 
Fuscin,  366 

Galactonic  acid,  84 
<5aIactose,  73,  84,  89,  391 


Galactose  from  cerebrin,  361 

,  relation    to    formation    of    gly- 
cogen, 216 
Gallacetophenon,    behavior   in   the    animal 

body,  482 
Gallic  acid  in  urine,  451 
Gallois's  inosit  test,  342 
Galtose,  75 

Gas,  exchange  of,  in  various  ages,  579,  580 
,  exchange  of,  through  the  skin,  529 
,  exchange  of,  in  starvation,  552,  557, 

559 
,  exchange  of,  in  various  conditions  of 
the  body,  352,  559,  561,  578,  580, 
581 
,  exchange  of,  in  the  muscles,  348,  352 
,  exchange  of,  with  various  food-stuffs, 

578 
,  exchange  of,  abstinence  value  of,  561, 
578 
Gases  of  the  blood,  530—535 
of  the  intestine,  296 
of  the  bile,  240,  535 
of  the  urine,  473,  536 
of  the  hen's  egg,  382,  383 
of  the  lymph,  184,  535 
of  the  milk,  395,  400,  536 
of  the  muscles,  346,  348,  352 
of  the  transudations,  190,  536 
in  pancreatic  digestion,  287 
Gastric  catarrh,  275  ~~~^ 

Gastric  contents.     See  Chyme. 
Gastric  fistula,  258 
Gastric  juice,  258 

,  secretion  of,  258,  259 

,  estimation     of     acidity     of, 

276—279 
,  relation  to  intestinal  putre- 
faction, 300 
,  artificial,  262 

,  action    of,    263—268,    270— 
276,  391,  398 
Gastric  mucosa,  258,  259 
Gelatin,  56 

,  relation    to    glycogen    formation, 

214 
,  putrefaction  of,  54,  294 
,  nutritive  value  of,  570,  571 
,  behavior  with  gastric  juice,  266 
,  behavior    with    pancreatic    juice, 
290 
Gelatin  and  the  detection  of  trypsin,  288 
Gelatin-forming  substances  (see  Collagen), 

54 
Gelatin  peptones,  56 
Gelatin  sugar.     See  Glyoocoll. 
Gelatinous  tissues,  316 
Gelatoses,  56 

,  relation     to    blood    coagulation, 
124 
Gentisic  acid,  451 

,  behavior  in  the  animal  body, 
482 


INDEX. 


C09 


Gentisic  aldehyde,  452 

(Jeihardfs  diacetic  acid   reaction,  509 

Cieriu  of  the  hen"s  egg,  .370 

(ilobin,  ti2,    147 

CJlobulitidal  bodies  in  seniiii,  181 

Cilobulins,    lU 

,  general   characteristics,   30 
in  urine,  487 
in  protoplasm,  lUO,   101 
.  See  also  the  different  globulins. 
Globuloses.  30 
Clucase,  133,  252,  253,  255 
CJlueocyanhydrin,  73 
lilucohcptoso,  73 
(.Mueonic.   72 
(ilueoprotein,    18 
Cilkicosaniin  from  chitin,  522 

from   cartilage.   318 
from  ovomucoid,  381 
Glucosan,  SO 
Cilucose.    See  Dextrose. 
Glucosides.  75.  77 
Glucosoxime,  73 
(Jlutamic  acid,  07 
Gluten  protein.  43 
Glutin.    See  Gelatin. 
Glutolin,  130 
Glutose,  75 
(ilycalanin.  58 
Glycerin  aldehyde,  79 

Glycerin,  relation  to  formation  of  glycogen, 
214 
,  solvent  for  enzymes,  11 
Glyeerophosphoric  acid,  103,178,199,204,237 
Glycerophosphoric   acid   in   urine,  459,   402 
Glycin.     See  Glycocoll. 
Glycocholic  acid,  227,  228,  239 

,  properties,  227,  228 

,  occurrence        in        excre-  i 

nients,  297 
,  occurrence    in    bile    from 

various  animals,   240 
,  absorption  of,  315 
,  behavior      to      intestinal 
putrefaction,  297 
Glycocholates  from  rodents,  228 
Glycocoll,  GO 

,  properties,  231 

,  formation  from  gelatin.  Tt^,  294 

,  formation     from     other     protein 

substances.  53,  59 
,  relation    to    formation    of    uric 

acid.  420,  429 
,  relation    to    formation    of   urea, 

412.  431,  470 
,  synthesis  with  glycocoll,  2,  440, 
480.  481 
Glycogen.  88.  100.  211—223 
,  origin  of,  214—218 
,  general  chemical   behavior.  212 
,  relation     to    muscular    aeWvity, 

348,  352 
,  relation  to  muscle  rigor,  347 


Glycogen,  relation  to  formation  of  sugar, 
217—222,  253 
,  occurrence  in  sputum,  545 
,  occurrence  in  nuiscles,  342 
,  occurrence  in  tlic  lungs,  545 
,  occurrence  in  the  lymph,  184 
,  occurrence    in     protoplasm,     100, 
105,  150,  197 
Glycolysis,  133,   184 
Glycolytic   enzyme,    1.33,  223 
Glyconucleoproteids,  50 
Glycoproteids,   l(i,  44—50,   102,  380 
Glycosuria,  220—224,  490 

,  alimentary,  220,  308 
Glycosuric  acid,  451 
Glycuron,  400 

Glycuronic   acid,   relation   to   formation   of 
glycogen,   214 
,  properties,  400 
,  conjugated,  445,  449.  400 
,  conjugation     of,     in     the 

body,  477,  482 
,  occurrence    in    cartilage, 
318,  400 
Glyoxyl  diureid.     See  Allantoin. 
Gmelin's  test  for  bile-pigments,  235 

test    for    bile-pigments    in    urine, 
494 
Goat's  milk,  390,  .397 
Goose-fat,  absorption  of,  312 
Gorgonin,  58 

Gout,  elimination  of  uric  acid  in,  427,  428, 
(haafian   follicles,  372 
(J rape-moles,  384 
(irape  sugar.     See  Dextrose. 
(Uiaiacum  blood  test,  491 
Guanin,   115 

,  properties    and    occurrence,     117, 
118 
in  urine.  435 
Guanin  calcium,  117 
Guanin  gout,  117 
Guano.  117,  427 
Guano-bile  acids.  228 
Guanovulit,  382 
Guanylic  acid,  109,  110 
Gulonic  acid  lacton.  400 
Gulose.  78,  83 
Gums,  various.  88 — 90 
,  animal,   45 
,  animal,  in  urine.  459 
Gunning-Leiben's  acetone  reaction,  SOS 
Giinzberg's  reagent  for  free  HCl,  277 

HjematatTometer,    539 

IIa>ma(in,   14S 

,  relation  to  bilirubin.  24.^ 
,  relation  to  urobilin,  243 
.  properties,    149 

llivmatinometer,  153 

llitmatinic  acids.   149 

Ha^matoblasts.   15(i 

Ilaematochlorin,  383 


610 


INDEX. 


Ha?niatociit.  1G9 
Hivnitosen,  377,  382 
Ha'inatoglobulin.     See  Oxy haemoglobin. 
HaMiiatoidiii,   152 

,  relation  to  bilirubin,  152,  233, 

243 
,  properties,  152 
,  occurrence  in  sputum,  545 
,  occurrence    in    corpora   lutea, 

373 
,  occurrence      in      excrements, 

302 
,  occurrence  in   sediments,   516 
Hsematolin,  150 

Hsematoporphyrin,    relation    to    bilirubin, 
151,  243 
,  relation      to      urobilin, 

151,  455 
,  relation      to       protein- 

chromogen,  289 
,  properties,  151 
,  occurrence      in      urine, 

455,  492 
,  occurrence      in      lower 
animals,  525 
Heematoporphyrinuria,  492 
Hsematoscope,  152 
Hsematuria,  490 
Ha>merythrin,  154 
Ha>min,   149,   150 
Ha-min  crystals,  150,  491 
Ha-niochromogen,  139,  147,  148 

,  properties  of,  148 
,  occurrence     in     muscles, 
338 
Hsemocyanin,  154 
Haemoglobin,  44,  143 

,  composition  of,  139 

,  properties  and  behavior,  143 

,  quantity   in   blood,    139,    171, 

172—178 
,  quantitative    estimation,    153, 

154 
,  behavior  in  tryptic  digestion, 

290 
.  See  also  oxyhfemoglobin  and 
the  combinations  of  haemo- 
globin with  other  gases. 
Haemoglobinuria,   490 
Hsemometer,  154 
Haeser's  coeflfieient,  474 
Hair,  51,  521 

,  ash  of,  521 
,  pigments  of,  524,  525 
Hair-balls,  .303 
Half- rotation,  76 

Halogens,  action  of,  on  proteids,  2.3 
Hammarsten's   reaction    for   bile-pigments, 
235 
reaction  erf  bile-pigments  in 
urino,  495 
Haptogen-membrano,  387 
Heat,  action  of,  on  metabolism,  579,  583 


Heat  of  combustion  of  various  food-stuflfs, 
554—556 
,  loss  of,  through  the  skin,  529,  583 
generated  in  plants,  2 
Helicoproteid,  16,  50 
Heller's  albumin  test,  26 

albumin  test  applied  to  urine,  485 
Heller-Teichmann's  blood  test,  491 
Hemialbumose,  35 
Hemicelluloses,  91 
Hemicollin,  56 
Hemielastin,  54 
Hemipeptone,  35 
Hemp-seed  calculi,  517 
Hen's  egg,  376—784 

,  incubation  of,  382,  383 
Herring,  spermatozoa  of,  59 
Heteroalbumose,  36,  38,  488 
Heteroxanthin,   115 

in   urine,   436 
Hexobioses,  84 
Hexon  bases,  68 
Hexoses,  78—84 

from  nucleoproteids,  50 
from  nucleic  acids,   110 
.  See  also  the   various  hexoses. 
High  altitude,  action  on  the  blood,  176 
Hippokoprosterin,  248 
Hippomelanin,  524 
Hippuric  acid,  440 

,  properties      and — j::eactions, 

442 
,  formation    in    the    body,    2, 

440,  441,  480 
,  cleavage  of,  440,  442 
,  occurrence  of,  440,  441 
as  sediment,  516 
Histidin,  19,  24,  59,  60,  69 
Histon,  61,  111,  167,  201 

in  urine,  490 
Histozyme,  443 
Hofmann's  tyrosin  test,  65 
Holothuria,  mucin  of,  48 
Homocerebrin,  360 — 362 
Homogentisic  acid,  446,  450 — 452 
Hopkins's    method    for    the    estimation    of 

uric  acid,  434,  435 
Hoppe-Seyler's  CO  blood  test,  146 

xanthin   test,   117 
Horn,  51,  521,  526 
Horn  substance  in  the  gizzard  of  birds,  52 

.  See   also   Keratins. 
Huckleberries,  coloring  matter  of,  in  urine, 

483 
Human  milk,  397^01 

,  behavior     in     the     stomach, 

270,  398 
,  composition,  398 
Humin  substances  in  urine,  453 
Humor,  aqueous,  194 
Iluppert's  reaction  for  bile-pigments,  235 

reaction     for     bile-pigments     in. 
urine,  495 


INDEX. 


611 


Hyalines,  48 

of  (lie  walls  of  hydatid  cysts,  52:} 
of  Rorsida's  substance,   101,   137, 
loU,  197 
Hyalogens,  48 
Hyaloinucoid,  SfiG 
Hyaloplasm,  10(i 
Hydatid  cysts,  iViS 
llydiiurvlic  acid,  342 
HydraMiiia,    177 
Hydrauinion.  384 
Hydrazons,   73 
Hydrobilirubin,  233,  234 

,  relation   to  urobilin,  454 
Hv«lrocolo  fluids,  1!)3 
Hydrochinon,  447,  483 
Hydrocliinon-sulphuric  acid,  443,  447 
Hydrochloric    acid,    secretion    in    stomach, 
2G0,  2GS.  275 
,  anti-fcrmentivo    action 

of,  274 
,  action   of,  on   secretion 
of    pancreatic    juice, 
283 
,  action    of,    on    pv'nrus, 

272 
,  quantity     of,     in     the 

<,'astric  juice,  260 
,  quantitative  estimation 
in    <ja.strie    contents, 
278,  27!) 
,  reagents    for    free   HCl 
in    gastric    contents, 
277 
Hydrocinnaniic  acid,  behavior   in  the  ani- 
mal   body,  441 
Hydrocyanic  acid,  action  on   peptic  diges- 
tion, 205 
,  action    on    tryptic    di- 
gestion, 289 
,  combination  w  i  t  h 

lupnioglobiu,  147 
Hydrogen   in   putrefactive   and    fcrnu'ntive 

processes,  8,  294.  29() 
Hydrogen  peroxide  in  urine.  473 

in  oxidations,  G 
,  decomposition      of,     by 
enzymes,   1 1 
Hydrolytic  cleavages,  8,  9 

.  See  also  the  various 
cleavages. 
Hydronephrosis  fluid,  406 
llydroparaciimaric  acid  in  putrefaction  in 

the  intestine.  294 
Hyoglycoeliolic  acid.  228 
Hypcralbuminosis,    178 
Hyperglycaemia,  220 
Hyperinosis,  178 
Hyperistonic  solutions,  159 
Hypinosis.  178 
Hypisotonic  solutions,  159 
Hypnotics,    relation    to    formation   of   gly- 
cogen, 214 


Hypoga^ic  acid,  98 

Hypophysis  cerebri,  iodothyrin  therin,  203 
Hyposulphites  in  the  urine,  4G2,  47G 
Hypoxanthin,  115 

,  relation  to  the  formation  of 
uric  acid,  429 

,  properties,   118 

,  passage  of,  into  urine,  435 

Ichthidin,  377,  382 
Ichthin,  382 

Ichthulin,   IG,  49,  377,  382 
Ichthylepidin,  58 
Icterus,  224,  244,  245 
in  blood,  180 
in  urine,  494 
Immunity,   14 

Incubation  of  the  egg,  382—384 
Indican  test,  Jaffe's,  448 

,  Obermeyer's,  449 
Indican,   urine,  447 — 449 

,  elimination  in  starvation,  297,447 
,  elimination  in  disease,  447,  448 
Indigo,  448       • 

in  sweat,  529 
in  urinary  sediments,  516 
Indigo  blue,  448,  453 
Indol,  pro])ertics,  295,  29G 

,  fornuition  from  protcid,  18,  20 

,  formation  in  putrefaction,  294,  297, 

443.  447 
,  behavior  in  animal  bodj*.  479,  482 
Indophenol  blue,  5,  7 
Indoxyl,  443,  447 

Indoxyl-glycuronic  acid,  447,  449,  482 
Indoxyl  red,  449 

Indoxyl-sulphuric  acid,  443,  447 — 449 
Inosinic  acid.  338,  340 
Inosit,  properties  and  occurrence,  341 
in  urine,  506 
,  relation   to   formation    of  glvcogen, 
214 
Intestinal   calculi.  303 
Intestinal   contents,  291—303 
Intestinal  fistula,  280.  293 
Intestinal  gases,  294.  290 
Intestinal   juice,  280—282 
Intestinal   mucosa,  280 
Intestine,   putrefactive   processes   in,  293 — 
300 
.  reaction   in.  293.  300 
.  absorption     in,    298—300,    304 — 

31G 
.  digestive  processes  in,  291 — 294 
Intracellular  enzyme  action,  10 
Inulin,  83,  88 

,  relation  to  formation  of  glycogen, 
214 
Inversion,  85,  216,  2G6,  280,  291,  308 
Invertin.   12.  8G.  280,  308 
Invert-sugar.  84 

Iodides  and  secretion  of  gastric  juice,  268 
Iodine  equivalent,  97 


012 


INDEX 


Iodine,  passage  of,  into  milk,  404 
,  passage  of,  into  sweat,  529 
,  passage  of,  into  saliva,  256 
Iodized  albuminates,  23,  58 
Iodized   fats,   327,   403 
lodo-cholalic  acid  compound,  229 
Iodoform,  behavior  in  the  animal  body,  477 
test,  Gunning's,  508 
test,  Lieben's,  508 
lodogorgonic  acid,  58 
lodospongin,  58 
lodothyrin,  201,  203 
lones,  relation  to  ferment  action,  12 
Iron  in  blood,  134,  170,  171 

in  blood-pigments,  139,   148,  150,  153, 

243 
in  bile,  238,  243 
in  urine^  472 

in  the  liver,  209,  210,  243 
in  milk,  395,  399,  401 
in  the  spleen,  199,  200 
in  muscles,  345,  354 
in  new-born,  199,  210,  401 
in  protein  substances,  7,   16,  31,   113, 

199,  207,  243 
in  cells,   121 
,  elimination  of,  238,  243,  256,  472 

and  blood  formation,   176,  377 
,  absorption  of,  176 
granules  in  the  spleen,   199 
Iron  salts,  elimination  by  the  urine,  472 
,  action  on  the  blood,  176 
,  action  on  trypsin  digestion,  289 
,  absorption   of,    176 
Iron    starvation,   565 
Iscliuria   in  cholera,  528 
Isocholesterin,  246,  248 

in  vemix  caseosa,  526 
Isoereatinin,  338,  339 
Isodulcite,   78 
Isodynamic  law,  556 
Tsoglucosamin,  74 
Isomaltose,  84,  86,  253,  285 

in  urine,  459 
Isosaeeharin,     relation     to     formation     of 

glycogen,  214 
Tsoftonie  solutions,  159 
Isotropous  substance,  332 
Ivory,  326 

Jaff6's  indican  test,  448 

creatinin  test,  424 
Janthinin,  526 

.fa panose,  nutrition  of,  585,  586 
Jaune  indien.  460 
Jocorin,  105,  172,  199 

,  propeities  and  occurrence,  209 
.Tequirity  bean,    14 
Jolles's  reaction  for  bile-pigments,  495 

Kairin,  action  on  the  urine,  483 
Kaufmann's   method   of   studying   metabo- 
lism, 553 


Kephalines,  359,  362 
Kephir,  392 

,  anti-putrefactive  action,  298 
Kerasin,  360,  362 
Keratinose,   52 
Keratins,  16,  51,  52 

,  properties,  51,  52 
,  behavior  in  the  stomach,  266 
,  behavior    with    pancreatic    juice, 
290 
Ketoses,  72,  74 
Kidneys,  406 

,  relation    to    formation    of    urie 

acid,  431 
,  relation  to  formation  of  urea,  414 
,  relation  to  formation  of  hippurie 
acid,  442 
Kjeldahl's  method  of  determining  nitrogen, 

417 
Knapp's  titration  method,  503 
Knee-joint  cartilage,  320 
Knop-Hiifner's     method     for     determining. 

urea,  421 
Koprosterin,  247,  302 
Kumyss,  392 
Kyestein,  516 
Kynurenic  acid,  451,  452,  463 

Laborer,  diet  of,  585,  590 
Lactalbumin,   16,  391 
Lactase,  281,  392  — ^ 

Lactates.     See  Lactic  acids,  also  344. 
Lactic-acid  fermentation,  76,  81,  271,  274, 

276,  342,  386, 
392 
in  intestine,  292. 

308 
in    stomach,  274, 

276 
in      milk,      386, 
396 
Lactic  acids,  342—345 

in   intestine,  293 
in  urine,  343,  429,  459 
in  bones,  324 

in  stomach,  260,  270,  274 
,  relation  to  foi'mation  of  uric 

acid,  429 
.  See  also  Paralactie  and  Fer- 
mentation lactic  acids. 
Laeto-caramel,  392 
Lacto-globulin,  391 
Lactones  of  vai'ieties  of  sugars,  72 
Lacto-phosphocarnic  acid,  391 
Lacto-protein,  391 
Lactose.     See  Milk-sugar,  391 
Laevo-lactic  acid,  342 
Laiose,  505 
Lanoccric  acid,  527 
Lanolin,  248 
Lanopalmitic  acid,  527 
Lanugo  hair,  384 
Lard,  absorption  of,  312 


INDEX. 


6i:] 


Latebra,  376 
Lsiuric  acid,  92 

in  butter,  388 

in  spermaceti,  98 
Laxatives,  action  nn  tlic  blood,  178 
Lead    colic,    elimination     of    urobilin     in, 

Lead  in  the  blood,  170 
in   the  liver,  211 
,  passage  of,  into  milk,  404 
Lecillialbumins,  31 

,  relation     to     secretion     of 

gastric  juice,  2G9 
,  relation     to     secretion     of 
urine,  405 
Lecithin,  properties,   occurrence,   etc.,    1U3, 
104 
in  milk,  399 
,  action  on  coagulation  of  blood, 

IGG 
,  putrefaction  of,  104,  297 
,  relation    to     muscular    activity, 
350 
Legal's  acetone  reaction,  503 

indol  reaction.  259 
Legumin  from  peas,  43 
Leinolic  acid,  92 
Lens  (see  Crystallin  lens),  367 
,  capsule  of,  3()7 
,  fibres  of,  367 
Leo's  method  for  determination  of  acidity, 
278 
sugar,  505 
Lepidoporphyrin,   525 
Lepidotic  acid,  525 
Lethal,  98 
Leucaemia,    blood,  115,  178 

,  uric  acid,  elimination   in,  200, 

427,  428 
,  xantliin    bodies    in,    115,    178, 
435 
Leuceines,  18 
Leucines,  18 
Leucin,  18,  62—64 

,  relation  to  formation  of  uric  acid, 

429 
,  relation  to  formation  of  urea,  412, 

476 
,  ])reparation,  65,  66 
,  properties,  62 — 64 
,  passage  of,  into  urine,  511 
,  behavior  in  the  animal  bodv,  412, 
476 
Leucin  ethylester,  64 
Leucinic  acid,  63 
Leucinimid.  19.  22 
Leucocytes,  relation  to  absorption,  306 

,  relation    lo    formation    of   uric 
acid,  430 
in  thymus  gland,  201 
Leueomaines,  14 

in  urine.  463 
in  muscles,  341 


Leuconudein,   163,  165,  106,  201 
Levulinic  acid,  78,  109 
Levuiose,  72,  73,  74,  78,  83,  84 
in  urine,  505 
,  relation    to  glvcogen   formation, 

215,  221 
,  absorption  of,  308 
,  behavior  in  dialtetics,  221 
in  transudations,  190 
Liehenin,  88 

Lieben's  acetone  reaction,  508 
Lieberkiihn's   alkali-alhuminate,    18.   32 

glands,  280 
Liebermann's  reaction  for  proteids,  27 
Liebermann-Hurchard's  reaction  for  choles- 

terin,  247 
Liebig's    titration    method    for   estimating 

urea,  418—421 
Ligamcntum  nuchse,  53,  54 
Lignin,  90 

Linseed  oil,  feeding  with.  327 
Lion's  urine,  425 
Lipaciditmia,  179 
Lipfemia,  179 

Lipanin,  absorption  of,  312 
Lipochromes,  134,  377 
Lipolytic  enzyme  in  the  blood,  134 
Lipuria,  511 
Lithium  iu  blood,   170 
Lithium  lactate,  344 
Lithium  urate,  432 
Lithobilic  acid,  304 
Lithofellic  acid,  231,  304 
Lithuric  acid,  463 
Liver,  206—211 

,  relation    to    coagulation    of    blood, 

168 
,  relation   to  formation   of  uric   acid. 

428.  431 
,  relation  to  formation  of  urea,  412, 

413,  414,  431 
,  blood  of,  173,  218 
,  proteids  of,  207 
,  fat  of.  208,  209 
,  quantity  of  sugar  in,  218 
Liver  atrophy,  acute,  yellow, 

,  elimination  of  ammonia  in. 

415 
,  elimination     of     urea     in, 

415 
,  elimination    of    leucin    f^nd 

tyrosin  in.  511 
,  elimination    of    lactic    acid 
in.  343.  459 
Liver  cirrhosis,  ascitic  fluid  in.  193 

,  action   of.  on   the  elimina- 
tion   of    ammonia     and 
urea,  415 
Liver  dextrin,  214 

Liver  extirpation,  elimination     of     ammo- 
nia with.  415.  428 
,  elimination  of  uric  acid 
with,  428 


614 


INDEX. 


Liver    extirpation,    elimination    of    lactic 
acids   with,   343,   428, 
459 
,  action  on  formation  of 
bile,  241,  242 
Lung  catheter,  539 
Lungs,  554,  555 
Luteins,  377,  378 

in  coi'pora  lutea,  373 
,  egg-yolk,  377 
in  serum,  134 
,  relation  to  hsematoidin,  373 
Lymph,  183—188 
Lymphagogues,  187 
Lymphatic  glands,  198 

Lymph-cells,  quantitative    composition    of, 
201 
.  See  also  Leucocytes. 
Lymph-fibrinogen.     See  Tissue-fibrinogen. 
Lysatin,  19,  69,  412 
Lysatinin,  19,  69,  289 
Lysin,  19,  24,  59,  68,  289 
Lysuric  acid,  68 

Mackerel,  flesh  of,  355 
Madder,  feeding  with,  344 
Magnesium   in  urine,  466,  472,  475 
in  bones,  322,  325 
in  myiscles,  345,  354 
.  See   also   various   tissues   and 
fluids. 
Magnesium  phosphate    in    intestinal    cal- 
culi, 303 
Magnesium  phosphate  in  urine,  466,  472 
Magnesium   phosphate   in   urinary   calculi, 

516,  518 
Magnesium     phosphate    in     urinary     sedi- 
ments, 514,  516 
Magnesium  phosphate  in  bones,  322 
jMagnesium  soaps  in  excrements,  301 
Malaria,  180 
Malic  acid,  behavior  in  the  animal  body, 

476 
Maltase,  86 

in  blood,  133 
Malt  diastase,  253 
Maltodextrin,  89 
Maltose,  85 

,  formation    from    starch,    89,    253, 

285 
,  absorption  of,  308,  309 
,  relation    to    glycogen    formation, 

216 
,  action  with  intestinal  juice,  280, 
291,  308 
Mammaiy  glands,  385,  403,  404 
Mandclic  acid,  479 
Man  in  poorhouse,  diet  of,  589 
Mannite,  78,  83 

,  relatirm     to     formation     of     gly- 
cogen, 214 
Mannosp,  75.  78,  83,  91 
Mannoso-cellulo.se,  91 


Mare's  milk,  396,  397 
Margarine  and  margaric  acid,  94 
Marsh-gas,  formation  in  putrefaction,  294,. 

296 
Maschke's  acetone  reaction,  424 
Meat  extracts,  action  on  secretion  of  gas- 
tric Juice,  259 
Meat  in  intestinal  tract,  307 
,  calorific  value  of,  554,  555 
,  digestibility   of,   272 
,  composition   of,   329,   354—356 
.  See  also  muscles. 
Meconium,  302 
Medulla  oblongata,  363 
Melansemia,    180 
Melanins,  524 

,  relation  to  blood-pigments,  524 
,  relation     to     proteinchromogen, 

289 
,  properties    and    occurrence,    524,. 
525 
in  the  eye,  366 
in  hair,  493 
Melanogen  in  the  urine,  493 
Melanoidic  acid,  524 
Melanotic  sarcoma,  pigment  of,  524,  525 
Melebiose,  87 
Melissyl  alcohol,  98 
Mellitsemia,  179 
Membranines,  48,  321,  367 
Menstrual  blood,   174 
Menthol,    behavior    in    the    anlmad    body,, 

482 
Mereapturic  acid,  482 
Mercury  salts,  passage  of,  into  milk,  404 
,  passage  of,  in  sweat,  529 
,  action  on  ptyalin,  254 
,  action   on  trypsin,  289 
Mesitylen,   behavior   in  the   animal   body, 

480 
Mesitylenic  acid,  480 
Mesitylenuric  acid,  480 
Metabolism,   dependence   of  external   tem- 
perature upon,  583 
in  various  ages,  579 
in   work   and   rest,   350—354, 

580—582 
in  diff"erent  sexes,  579 
in  starvation,  556 — 562 
with     different     food  -  stuffs,. 

566—578 
in  sleep  and  waking,  582 
,  calculation  of  e.xtent  of,  549 — 
554,  561,  562 
Metalburain,  374 

Metaphosphoric    acid,    constituent    of    nu- 
eleins,     31,     108,. 
112 
,  as  reagent  for  pro- 
teids,  26,  485 
Methaemoglobin,  144 

in  blood  in  poisoning,  180 
in  urine,  490 


INDEX. 


615 


:Motlial.   98 

ilt'tliaiip,    formation    in    putrefaction,    20, 

2!t4,  2!IG 
:\letlii)sc',  71t 
Aletliylcnitan,   79 
Aletlivl  j;lvcot'oll.'"   See  Saicosin. 
]\lotlivl«j;iiiinidin,  339,  423 
Metliylfiuandin-acetic  acid.    See  Creatin. 
iMetliylli_\daiidi)inie  acid,  47U 
Metliyl   iiidol.     See  Skatol. 
Methyl  mercaptan  in  proteid  putrefaction, 
20,  54,  294,  29G 
in  urine,  483 
Methyl  pentose.     See   Rhamnose. 
Methyl    pyridin,    behavior    in    the    animal 

body,    479 
Methvl-pvridvl-ammonium  hydroxide,  483 
Methvluramiii,  339.  423 
Methyl  xanthin,   115,  435,  430 
Mett's  method  of  estimating  pepsin,  2G4 
Micrococcus  restituens,  30G 
Micrococcus  ure^e.  10,  514 
Microorganisms  in  intestinal  tract,  12,  274, 

294,  297,  301 
Milk,   385—405 

,  secretion  of,  402 — 404 

,  consumation    of,    in    intestine,    307, 

313 
,  blue  or  red,  404 

,  anti-putrefactive  action  in  intestine, 
298,  444 
in  disease,  404 
,  passage  of  foreign  bodies  into,  404 
,  behavior  in   the   stomach,  270,  274, 

398 
,  action    on    the    secretion    of   gaslric 

juice,   259 
,  action  on  tiie  secretion  of  pancreatic 

juice,   284 
.  See  also  ditlerent  varieties  of  milk. 
Milk- fat.  388.  397 

,  analysis  of,  394 
,  formation    of,   403  . 
Milk-globules  frorm  cow's  milk,  387,  388 

from  human  milk,  397 
Milk-plasma,  388 
Milk-sugar,  87.  391,  392 

,  relation    to   formation    of   glj'- 

cogen.  210 
,  properties,  391,  392 
,  fermentation,  38(>.  392.  390 
,  inversiom  of.  281,  291,  392 
,  calorific  value  of,  554 
,  quantitative  estimation,  395 
,  absorption  of,  308 
,  passage  of,  into  urine,  210,392, 

505 
,  origin  of,  385,  403,  404 
Millon's  reagent,  27 

Mineral    acids,    alkali-removing   action    of, 
408.  471,   535,  563 
,  anti-fermentive    action    of, 
274 


Mineral    acids,   action   on   the   elimination 

of  ammonia,  471,  505 
Mineral   bodies,  elimination   in  starvation, 
500 
,  insuflicient       supply       of, 

502—500 
,  behavior  in  the  organism, 

503 
.  See  also  the  various  fluids, 
tissues,  and  juices. 
Mitoplasm,  100 
Mixture  of  the  nitrogenous  substances  in 

tiic  urine,  411,  427,  428 
Modified  proteids,  29 

Mohr's  titration  method  for  chlorine,  404 
Molisch's  sugar  test,  82 
Monamido  acids,  02 
Monosaccharides,  72 — 84 
Moore's  sugar  test,  80 
Morner-Sjoqvist's     method     of    estimating 
urea,  421 
method     of     estimating 
acidity,  278 
Morner's  reaction  for  aceto-acetic  acid.  510 
Morphin,  passage  of,  into  urine,  483 
,  passage  of,  into  milk,  404 
Mucic  acid,  84,  89,  392 

,  relation   to  formation   of  gly- 
cogen, 214 
ilucilages,  vegetable,  88,  90 
Mucin,  10,  45,  40 

in  sputum,  545 
in  connective  tissue,  316 
in  urine,  402,  489 
in  salivary  glands,  45,  249 
,  detection  of,  in  urine,  489 
Mucin-like  substances  in  bile,  220 

in  juinc,  402.  489 

in  kidneys.  400 

in      thyroid      gland, 

201 
in  synovial  fluid.  19» 
Mucinogjpn,  47,  250 
Mueinoids.     See  Mucoids. 
Mucin  peptone,  46.  266 
Mucoids,  16,  47,  48 

in  ascitic  fluids.  190,  193 
in  the  vitreous  humor,  317.  307 
in  the  cornea,  321 
Mucose,  40 

Mucous  glands,  45,  249 
Mucous  membranes  of  the  stoi.iach,  2.i7 
Mucous  tissue,  310 
Mucus  of  the  bile,  225.  239 

of  the  urine,  400,  462,  489 
of  synovial  fluid,  195 
Mulberry  calculi,  518 
Murcxide  test,  433 

Muscle,  coagulation  of.  334,  336,  340,  357 
Muscle-fibres.  .3.32 
Muscle-pigments.  337 
Muscle-plasma.  333 
Muscle-serum,  333 


616 


INDEX. 


;Rlii>(le-stroma,  335 
Wuscle-sugar,  342 
Wuscle-syntonin,  336 
Jtlusoles,  striated,  356 

,  unstriated,  332 — 356 

,  blood  of,  174,  348,  349 

,  chemical    processes    in    work    and 

rest,  347—354 
,  chemical   processes   in   rigor,   346, 

347 
,  proteids  of,  333 — 337 
,  extractives  of,  338 — 345 
,  pigments  of,  337 
,  fat  of,  345,  352,  355 
,  gases  of,  346,  348,  352 
,  calorific  value  of,  554,  555 
,  mineral  bodies  of,  345,  356 
,  amount  of  water  in,  355 
,  composition  of,  354 
INIuscosamin,  40 

Muscular  energy,  origin  of,  352 — 354 
Muscular  force,  chemical  processes  in  mus- 
cles, 347—354 
,  action    of,   on   urine,   408, 

423,  425,  461 
,  action  of,  on  metabolism, 
347—354 
Musculin,  16,  335,  337 
Mussels,  glycogen  of,  211 
Mustaid-seed  oil,   action   on   the   secretion 

of  pancreatic  juice,  284 
Mutton-fat,  feeding  with,  327 

,  absorption  of,  312,  313 
Mvco-protein,  17 
Mveline  forms,  104,  359 
Myelines,  359 
Myoalbumose,  335 
Myoalbumin,  335 
Myogen,  337 
Myogen  fibrin,  334,  337 
Myogiobulin,   335 
Myolipematin,  338 
Mvoproteid,  337 
Myosin,  334,  337 

,  in  leucocytes,  156 
,  absorption  of,  304 
Mvosin  ferment,  336 
Myosin  fibrin.  334,  337 
Myosinogen,  336,  337 
Mvosinoses,  36 
IMvricin,    98 
Myricyl  alcohol,  98 
Mvristic  acid  in  animal   fat.  92 
in  butter,  388,  397 
in  bile,   237 
in  wool-fat,  527 
Myxoedema,  202,  203,  317 

Nnils,  51,  521 

N;.;  Iithalin,  action  on  urine,  483 

,  behavior  in  the  animal  body, 
479 
2saphthol-glycuronic  acid,  482,  483 


Naphthol,  reagent  for  sugar,  82,  500 

,  behavoir    in    the    animal    body, 
482,  483 
Narcotics,  relation  to  glycogen  formation, 

214 
Native  proteids,  29 
Navel  cord,  mucin  of,  45,  47,  317 
Neossin,  48 
Nerves,  364 
Neuridin,  359,  362,  376 
Neurin,  103 

,  in  suprarenal  capsule,  204 
,  in  protagon,  359 
Neurochitin,  364 
Neurokeratin,  51,  358,  364 
Neutral  fats.     See  Fats. 
Nickel  salts,  behavior  to  amido-acids,  68 
Nicotin,  action  on  quantity  of  CO:.,  in  the 

stomach,  271 
Nitrates  in  the  urine,  470 
Nitric-oxide  haemoglobin,   147 
Nitro-benzaldehyde,    behavior    in    the   ani- 
mal body,  480 
Nitro-benzoic  acid,  22,  480 
Nitro-benzyl  alcohol,  481 
Nitro-cellulose,  91 
Nitro-hippuric  acid,  480 
Nitro-phenyl-propiolic     acid,     reagent    for 

sugar,     82, 
500 
,    behavior     in 
the  animal 
body,  449 
Niti'o-toluol,  behavior  in  the  animal  body, 

4§2 
Niti'o-tyrosin  nitrate,  65 
Nitrogen,  combined,  amount  of,  in  intesti- 
nal       evacuations, 
548,  549 
,  in  meat,  356,  550 
,  in   urine,  411 
,  estimation        of,        in 
urine,  417,  421 
Nitrogen  elimination  in    work    and    rest, 
350,      351,      352, 
580 
in     starvation,     557, 

558 
with    various    foods, 

566—576 
by  the  intestine,  307, 

548,  549 
by    the    urine,    411, 
467,    469,    548— 
550 
by      the      epidermis, 

549 
by  the  sweat,  528, 
548 
,  relation  to  the 
elimination  of 
phosphoric  acid, 
467 


INDEX. 


017 


Nitrogen  elimination,  relation  to  tlip 
eliininatioii  of 
sulphuric  acid, 
4U<J,  550 
"  ,  relation  to  di;,'estivc 
activity,  471, 
548,  570 
Nitrogen,  free,  in  blood,  530 

,  in  intestine,   290 
,  in  stoniacl),   271 
,  in  secretions,  534 
,  in  transudations,  536 
Nitrogen  in  the  jjrotcid  molecule,  17,  18 
Nitrogenous  deficit.  549 
Nitrogenous  equilibrium,  549 

,  wit  h       various 
foods,     567, 
569,  572,  573, 
575 
Nitroso-indol  nitrate,  295 
Nubecula,  400,  402 
Nucleic  acids,  50,  107,  109—111,  113 
in   the   urine,   489 
,  combination    of,    with    pro- 
tamins,  371 
Nuclein  bases,  49,  50,  107,  108,  H!!).  113—120 

in  the  urine,  43.') 
Nucleins,  50,   107,   108,   112.   113 

,  relation    to    elimination     of    al- 

loxuric  bases,  435 
,  relation    to    formation    of     uric 

acid,  429,  430 
.  relation   to  elimination  of  P.O, , 

406 
,  absorption,  550 

,  behavior  with  gastric  juice,  266 
,  behavior   with    pancreatic   juice, 
290 
Nuclein  plates,  157 
Nucleo-albumins,  16,  30 

in  the  bile,  226 
in  the  urine,  462,  489 
in  the  kidneys,  406 
in  protoplasm,  .30,   101 
in  synovial  fluid,  195 
in  transudations,   189,  190, 
192 
,  behavior   in   pepsin   diges- 
tion. .30,  265.  398 
Nucleo-histon,  16,  101,  111 

,  relation    to    coagulation    of 
blood,  164,  166 
in  urine,  490 
Nucleo-proteids,  16,  31,  50,  108,  HI,  112 
in  the  liver,  207 
in  gastric  juice,  260.  261 
in  mammary  glands,  385 
in   muscles.  "336,  359 
in  the  kidneys.  405,  406 
in  the  pancreas.  282 
in  protoplasm,   101 
in    cell    nucleus,    106.    Ill, 
112 


Nucleo-proteids,  as  oxygen  carriers,  7 

,  behavior    in    pepsin    diges- 
tion, 50,  112,  206 
Nucleon,  340 

in  milk,  .391,  .399 
Nucleosin,  110 
Nuck'othymic  ac' »,  110 
Nutrition  requirements,  508 

of  man,  584-590 
Nylander's   reagent.      See   Almcn-llottger's 
sugar  test. 

Obermeyer's  indican  test,  440 

Obermiiller's  cholesterin   reaction,  247 

Odoriferous  bodies  in  the  urine,  516 

Qulema,  subcutaneous,  fluid  from,  195 

Oertel's  diet  cure,  590,  .591 

Oesophagus  fistula,  2.58 

Oleic  acid,  95 

Olcin,  94,  95 

Oliga-mia.  177 

Oligocytha?mia,  177 

Oliguria.  475 

Olive  oil,  absorption  of.  312 

,  action  on  the  secretion  of  bile,225 
Onions,  behavior  with  saliva,  255 
Onuphin,  48 
Oocyanin,  382 
Oorodein,  382 
Opalisin.  388,  398 
Opium.  404 
Optograms,  366 
Organic  acids,  behavior  in  the  animal  body, 

407,  401,  470 
Organized  proteids,  568,  569 
Organs,  loss  of  weight  in  starvation,  561 
Organs  of  generation,  370 — 385 
Ornithin,   19,  68,  480.  481 
Ornithuric  acid.  08.  480 
Orthonitro-toluol.  482 
Orthonitro  -  phenyl  -  propiolic      acid.        See 

Nitro-phenvl-propiolic  acid. 
Orylic  acid.  391 
Osamins,  75 

Of^amincs  of  varieties  of  sugar,  75 
Osazones.  73 

Osmosis,  relation  to  absorption,  187,  315 
Osmotic  pressure  of  blood.  159 
Osone,  74 

Os.sein,  55.  321,  .324 
Osteomalacia,  324,  325 

,  lactic  acid  in   urine,  343 
Osteoporosis.    See  Osteosclerosis. 
Osteosclerosis.  324 
Otoliths,  .369 
Ovalbumin,  16.  379 

,  behavior  in  the  animal  body, 
131.  380 
Ovarian  cysts.  373—376 
Ovaries.  .372 
Ovglobulin.  379 
Ovomucin.  379 
Ovomucoid,  48,  380,  381 


618 


IM>&'X. 


Ovovitellin,  16,  376 

Ovum,  376—384 

Oxalate  calculi,  517 

Oxalate  of  lime.     See  Calcium  oxalate. 

Oxalates,  action  on  blood  coagulation,  124 

Oxalic  acid  in  the  blood,  17!) 

in  the  urine,  438,  439 
.  behavior   in   the   animal   body, 
438,  476 
Oxaluria,  439 
Oxaluric  acid,  426,  438 
Oxamid,  18 
Oxidases,  7 
Oxidation  ferment,  6 

Oxidations,   1—9,  142,  221,  294,  330,  413,  414, 
429,  443,  447,  454,  476,  477,  478,  480,  537 
Oximes,  73 
Oxonic  acid,  426 

Oxyacids,  formation  in  putrefaction,  294 
,  passage  of,  in  urine,  294,  450 
,  passage  of,  in  the  sweat,  529 
Oxybenzoic   acid,   behavior   in   the   animal 

body,  480 
Oxybenzols,  479 
Oxybutyric  acid  in  the  blood,  535 

,  passage  of,  into  the  urine, 
471,  510 
Oxycarnic  acid,  44 
Oxyfatty  acids,  92 

Oxygen,  consumption  in  work  and  rest,  348, 
352 
in  starvation,  559,561 
by  the  skin,  529 
Oxygen,  activity  of,  4  -7,  142 

in  the  blood,  531,  536—540 

in  the  intestine,  296 

in  the  lymph,  184,  535 

in  the  stomach,  271 

in  the  swimming-bladder  of  fishes, 

543 
in  secretions,  535,  536 
in  tran.sudations,  536 
,  combination  of,  in  the  blood,  140, 

141,  536,  539,  540 
,  tension  of,  in  blood,  537 — 541 
,  tension  of,  in  expired  air,  538 — 540 
,  action  of  CO..  in  expired  air,  542 — 

544 
,  lack  of,  action  on  proteid  destruc- 
tion, 343,  350,  351,  411 
,  lack   of,   action   on   elimination  of 

lactic  acid,  343,  459 
,  lack  of,  action  on  elimination  of 

sugar,  343,  459 
,  specific  capacity,  541 
Oxygon  carriers,  7 — 8,  142 
Oxygen,  calorific  value  in  the  combustion 

of  different  foods,  553 
Oxygen  consumption  in  the  blood,  144,  532 
Oxyhfematin,  148 
Oxyhaemocyanin,  154 
Oxyhsemoglobin,  140 

,  dissociation  of,  140,  551 


Oxyhsemoglobin,  properties  and  reactions, 
140,  141 
,  quantity  of,  in  the  blood, 

139,  171,  172,  177 
,  quantity   in   the   muscles, 
337 
■     ,  passage  of,  into  the  urine, 
490 
,  behavior      with       gastric 

juice,  266 
,  behavior  with  trypsin,291 
Oxyhydro-paracumaric  acid,  451 
Oxymandelie  acid,  451,  452 
Oxynapthalin,  479 
Oxynitro-albumin,  22 
Oxyphenyl-acetic  acid,  64,  294,  451,  481 
Oxyphenyl  -  amido  -  propionic     acid.        See 

Tyrosin. 
Oxyphenyl-propionic  acid,  23,  294,  451,  482 
Oxyproteic  acid  in  urine,  461 — 463 
Oxyproto-sulphonie  acid,  23 
Ozone,  3 

Ozone  exciter,  142 
Ozone  transmitter,  142 

Palmitic  acid,  94 
Palmitic-acid  ester,  98 
Palmitin,  94 
Pancreas,  282,  283 

,  relation   to   glycolysis,    133,   224,. 

283 
,  extirpation  of,  actioii~?m  absorp- 
tion, 307,  310—314 
,  extirpation     of,     elimination     of 

sugar,  221—223 
,  charge   of^   200 
,  change  during  secretion,  282 
Pancreas  diabetes,  222 
Pancreas  proteid,  77,  283 
Pancreas  rennin,  290 
Pancreatic  casein,  290 
Pancreatic  juice,  283 

,  secretion  of,  283,  284 
,  enzymes  of,  284 — 291 
,  action      on      food-stuffs, 
282—290 
Parabanic  acid,  116,  426 
Paracasein,  390 
Parachymosin,  267 
Paracresol,  formation  in  putrefaction,  294, 

443,  444 
Paraglobulin.     See  Serglobulin. 
Parahaemoglobin,   141 
Paralactic  acid,  342,  343 

in  the  blood,  134,  172,  344 
,  relation    to    formation    of 

uric  acid,  429 
,  properties  and  occurrence, 

343,  345 

,  formation    from   glycogen, 

344,  346 

,  formation  in  osteomalacia 
bones,  325 


INDEX. 


619 


Paralactic  acid,  formation  in  muscle  dur- 
ing worlv,  34'J,  352 
,  formation,  in  rigor  mortis, 

,  formation,      in      lack      of 

oxygen,  344,  34'J,  45U 
,  formation,       in       animals 
witii    extirpated    livers, 
344,  4.Ji) 
,  passage  of,  into  the  urine, 
42'J,  459 
Paralbumin,  374 
Paralytic  .saliva,  250 
Paramidophenol,  478 
Paramucin,  375 
Paramyosinogen,  335 
Paranuclein.     See  Pseudonuclein. 
Para-oxyphenyl-acetic  acid,  204,  450,  451 
Paraoxyphenyl  propionic  acid,  450,  451 
Paraoxvpropiophenon,   behavior   in   animal 

body'  482 
Para peptone,  2G5 
Paraxanthin,  115,  436 

in   urine,  43(5 
Parietal  or  delomorphic  cells,  257 
Parotid,  249 
Parotid  saliva,  251 
Parovarial  cysts,  375 
Pea  legumin,  43 
Pemphigus  chronicus,   195 
Penicillum  glaucum,  63 
Pentacrinin,   526 

Pentamethylendiamin.     See  Cadaverin. 
Pentosanes.  77 
Pentoses,  77 

,  relation   to  glycogen   formation, 
78,  214 
in  urine,  506 
in  pancreas,  78 
in  nuclein  bases.  109 
in    nudeoproteids,    50,    78,    208, 
385 
,  relation    to    elimination    of   hip- 
puric  acid,  442 
Penzoldt.  acetone  reaction,  509 
Pepsin,  260 

,  properties,  261 

.  detection  in  gastric  contents.  276 
,  quantitative  estimation.  263,  264 
,  occurrence  in  the  urine,  314,  462 
,  occurrence  in  muscles.  338 
,  action  on  proteid.  263 
,  action  on  other  bodies,  266 
Pepsin-like  enzyme.  260.  261 
Pepsin  digestion,  263.  267 

.  products  of,  260,  265,266 
Pepsin  glands,  257 
Pepsin-hydrochloric  acid,  266 
Pepsinogen,  257,  269 
Pepsin  test,  263 
Peptochondrin,  318 
Peptones,  33—10 

in  putrefaction,  20,  294 


Peptones  in  pepsin  digestion,  33 — 39,  266 
in  trypsin  digestion,  .33 — 39,  285* 
,  assimilation  of,  322 — 325 
,  relation   to  amylolysis,  256 
,  preparation,    40 
,  nutritive  value  of,  306,  571 
,  absorption  of,  304,  306 
,  passage  of,  into  urine,  305,  487 
,  action  on  the  secretion  of  gastric 
Juice,  259 
Peptone-plasma,  124,  162 

,  carbon-dioxide  tension,  54,'; 
Peptonuria,  520 
Pericardial  fluid,  189,  191 
Perilymph,  3(59 
Period  of  incubation,  383 
Peritoneal   fluid,   189,   192 
Permeability  of  the  blood  corpuscles,  160 
Peroxyprotic  acid,  23 
Perspiratio  insensibilis,  548 
Pettenkofer's  test  for  bile  acids,  227 

respiration  apparatus,  544 
Phacozymase,  368 
Phaseomannit,  341 
Phenaceturic  acid,  443,  479,  480 
Phenol-glycuronic  acid,  444,  482 
Phenol-sulphuric  acid  in   the   urine,   443 — 
446 
in  sweat,  528 
Phenols,  elimination    bv    the    urine,    299. 
443—450,  478-^81 
in  starvation,  297 
,  estimation   in   the  urine,  44.5.  448 
,  action  on  the  urine.  446.  483 
,  formation     in     putrefaction,     21. 

294—443,  444 
,  behavior  in  the  animal  body,  294 
Phenyl-acetic  acid,  formation  in  putrefac- 
tion, 22.  294 
,  behavior  in  the  animal 
body,  479 
Phenylalanin,    66.      See    Phenylamidopro- 

pionic  acid. 
Phenvl-amido-acetic  acid,  behavior  in  the 

animal  body.  479.  480 
Phcnyl-amido-propionic  acid,  23 
Phenvl-aniidn-])roi)ionic    acid,    behavior    in 

the"  animal  body.  478.  480 
Phcnyl-glucosazone.  82 
Phenyl-glucoshydrazine.  73 
Phenyl-hydrazine  test,  81 

in  the  urine,  498 
Phenyl-lactosazone,  392 
Phenyl-maltosazone,  86 
Phenyl-propionic  acid,  behavior  in  the  ani- 
mal body.  441.  479 
Phenvl-propionic    acid,    formation    in    pu- 
trefaction. 23,  294,  441 
Philothion.  4 
Phlebin.  138 
Phlorhizin.  219.  507 
Phlorhizin  diabetes.  219.  507 
Phloroglucin  as  reagent,  78,  277,  506 


620 


INDEX. 


Phosjphate  calculi,  518 
Phosphate  diabetes,  4G7 
Phosphates  in    urine,    407,    466—469,    484, 
514—510 
See    also    the    ditierent    phos- 
phates. 
Phosphocarnic  acid,  43,  338,  340 

in  the  milk,  391 
in   the  urine,  462 
in     relation     to     the 
elimination    of    CO2 
and  lactic  acid,  347 
in  relation  to  muscu- 
lar    activity,     352, 
354 
Phospho-glyco-proteid,  44,  49 
Phosphoric'  acid,  elimination  by  the  urine, 
466,  469,  472 
,  formation     in     muscular 

activity,  350 
,  physiological  importance, 
'121 
Phosphorized    combinations    in    the   urine, 

462 
Phosphorus     poisoning,     action     on     the 
elimination     of 
ammonia,  415 
,  action       on       the 
elimination     of 
urea,  415 
,  action       on       the 
elimination     of 
lactic  acid,  340, 
459 
,  fatty       degenera- 
tion caused  by, 
208,  328 
,  change      in      the 
urine,  340,  415, 
511 
Photomethsemoglobin,  145 
Phrenosin,  361 

Phthalic  acid,  behavior  in  the  body,  478 
Plivlloporphyrin,  139 
Phymatorusin,  524 

in  the  urine,  493 
Physetoelic  acid,  98 
Phytosterines,   246 
Phytovitellin,  43 

a-Picolin,  Ijehavior  in  the  animal  body,  481 
Picric  acid,  reagent  for  protoid.  26,  488 
,  reagent  for  creatinin,  424 
,  reagent  for  sugar,  82,  500 
Pigment  calculi,  245 
Pigments  of  the  eve,  365 — 307 

of  the  blood,   138—155 

of    the     blood-serum,     134,    377, 

378 
of  the  corpora  lutea,  152,  376 
of  the  egg-shell.  382 
of  the  fat -cells.  320 
of  the  bile,  233—237,  240,  242 
of  the  urine,  453 — 459 


Pigments  of  the  skin,  524 — 527 

of  the  lobster,  382,  525 
of  the  liver,  208 
of  the  muscles,  337,  338 
of  lower  animals,  525,  526 
,  medicinal  pigments  in  the  urine, 
483,  496 
Pigmentary  alcoholia,  240 
Pig's  milk,  397 
Pike,  flesh  of,  350 

,  stomach  of,  202 
Pilocarpin,  action  on   the   secretion  of  in- 
testinal juice,  280 
,  action    on    the    elimination    of 

COv  in  the  stomach,  271 
,  action     on     the     secretion     of 

sweat,  528 
,  action     on     the     secretion     of 

saliva,  250 
,  action    on    the    elimination    of 
uric  acid,  428 
Piperazin  solvent  for  uric  acid,  432 
Piperidin,  432 
Piqiire,  221 

Piria's  tyrosin  test,  05 
Placenta,  363 

Plants,  chemical  processes  in  the  same,  1,  2 
Plasma.     See  Blood-plasma. 
Plasmoschisis,  162 
Plastin,  106,  113 

Plattner's  crystallized  bile,  226  ^^ 
Plethora  polycythsemia,  170 
Pleural  fluid,  189,  191 
Plums,  action   on  the  elimination   of  hip- 

puric  acid,  441 
Poikilocytosis,  177 
Poisonous  proteids,  48 
Polarization  test,  499 
Polycythsemia,  170,  181 
Polyperythrin,  520 
Polysaccharides,  87—92 
Polyuria,  475 
Pons  varolii,  303 
Pork-fat,  absorption  of,  313 
Potassium  combinations,  division  of,  in  the 

form-elements  and  fluids,  121 
Potassium  combinations,  elimination  of.  in 

fevers,  470 
Potassium  combinations,  elimination  of,  in 

starvation,  471 
Potassium    combinations,    elimination    by 

the  saliva,  250 
Potassium  combinations  in  the  urine.  479 
Potassium    chlorate,    poisoning   with,    144, 

184 
Potassium  phosphate  in  yolk  of  eggs,  370 
in  muscles,   345 
in   cells,    121 
Potassium  sulphocyanide  in  the  urine,  401 
in     saliva,     251, 
252 
Potatoes,  consumation  of,  in  the  intestine, 
310 


INDEX. 


621 


Potential  energy  ot  various  foods,  554 — 55G 

l'ic<,'l()l)ulin,   101,   112.  103 

Preputial  secretion,  520 

Primary  albuinoses,   37 

Prisoners,  footl-ration  for,  589 

Propepsin,  2<!'J 

Propetones,  33 

Propylamin,  solvent  for  uric  acid,  432 

Propyl    benzol,  47!) 

I'ropyien   j;lyi(il,   relation    to    formation   of 

glyeogta,  214 
Prostatic  calculi,  372 

secretion,  370,  371 
Prostetic  group,  50 
Prota-ron,  105,  358,  300 
Protalbumose,  30 
Protamin,   15,  24,  59 
Proteid,  separation  from  fluids,  29 

,  approximate     estimation     in     the 

urine.  488 
,  circulating     and     tissue     proteid, 

508 
,  action    on    the    formation    of   gly- 
cogen, 215,  210 
,  active,  4 

,  living  and  dead,  4 
,  detection  of,  25 — 28 
,  detection  of,  in  urine,  483 — 490 
,  quantitative  estimation  of,  28 
,  quantitative      estimation      of,      in 

urine,  488,  490 
,  quantitative      estimation      of,      in 

milk,  393,  394 
,  absorption  of,  304—308 
,  passage    of,    into    the    urine,    343, 

401,  402,  483 
,  heat  of  combustion  of,  554,  555 
,  digestibility   in  gastric  juice,  264, 

205,  272—270 
,  digestibility    in    pancreatic    juice, 
288,  289 
Proteid  bodies    in  general,  16 — 44 

,  poisonous,   13,   14,  43 

,  summary    of    the    various, 

10,  29—44 
,  vegetable,  43 

.  See  also  the  various  proteid 
bodies  of  the  tissues  and 
fluids. 
Proteid  metabolism  in  work  and  rest,  350 — 
354,  580 
in  starvation,  557.  558 
in  various  ages,  580 
with     different     foods, 

560—577 
after  feeding  with  thy- 
roid extracts,  202 
Proteid  putrefaction,  13,  20,  294—300,  441, 

443—450 
Protein  chromogen,  20,  289 
Protein  substances,   15 — 71.     See  also  indi- 
vidual protein  bodies. 
Proteoses,  30.    See  Albumoses. 


Prothrombin.   127,   103—105 

Protic  acid,  338 

Protocatechuic  acid,  behavior  in  the  body, 

440 
Protoelastose,  54 
Protogclatose,  57 
Protogen,  33 
Protone,  00 
Protoplasm,    101 

Protoplasm    poisons    and    proteid    destruc- 
tion, 411 
PseudolutMuoglobin,   138,   143 
Pseudolevulose.    75 
Pseudomucin,  47.  375 

in  ascitic  fluids,   193 
in  the  gall-bladder,  241 
Pseudonucleic  acid.   lOS 
Pseudonucleins,  30.  107 

from  casein,  205,  390,  398 
from  vitellin,  370 
,  consumation     and     absorp- 
tion, 299,  550 
Pseudotagatose.  75 
Pseudoxanthin.  341 
Psittacofulvin.   525 
Psyllosteryl   alcohol.  526 
Psyllosteryl   ether,   520 
Ptomaines,   13,  22 

in  the  urine,  403,  512 
Ptyalin,  252 

,  behavior   with   hvdrochloric  acid, 

254 
,  action  on  starch,  253 — 257 
Pulmotartaric  acid.  545 
Purin,   114 

Purin   bases,   110—114 
Purin  nucleus,  114,   115 
Purple,  525 
Purple  cruorin.  143 
Pus,  190—198 
,  blue.  198 
in   urine,  493,  494 
cells.   197 
serum,   196 
Putrescin,  13,  09 

in  intestine.  512 
in  the  urine.  403,  512 
Pyin.   192,   190,   198 
Pvinic   acid,    198 
Pyloric  gland.  257—269 
Pyloric   secretion,   269 
Pyocyanin,  198 

in   sweat,  529 
Pyogenin.  197.  301 
Pyosin.  197.  301 
Pyoxanthose.   198 

Pyridin.  behavior  in  the  body,  483 
a-Pyridin-carbonic  acid.  481 
a-P.vridinuric  acid.  481 
Pyrocatechin.   44(! 

,  occurrence  in  urine,  440 
,  occurrence      in      suprarenal 
capsule,  204 


622 


INDEX. 


Pyrocatechin,  occurrence  in  transudations, 

"190,  195 
PATOcatechin-sulphuric  acid,  443 — 446 
Pyiomucic  acid.  481 
Pyromucin-oiuithuric  acid,  481 
Psychical  period  of  secretion,  259 
Putrefactive  processes,  5,  13,  20 

in    intestines,   294—300,   441, 
443—452 

Quadriurates,  432,  514 
Quercite,  78 

,  relation    to    glycogen    formation, 
214 
Quercitin,  78 
Quinic  acid,  behavior  in  the  animal  body, 

441 
Quinin,  passage  of,  into  urine,  483 
,  passage  of,  into  sweat,  529 
,  action    of,    on    the    elimination    of 

uric  acid.  428 
,  action  on  the  spleen,  200 
Quotient,  respiratory,  330,  352,  552,  582 

Racemie  acid,  behavior  in  the  animal  body, 

470 
Pauhitis,  bones  in,  324,  325 
Radishes,  behavior  with  saliva,  255 
Paifinose,  87 

Picducing  substances,  formation  of,  in  pu- 
trefaction and  fer- 
mentation, 5,  296 
,  occurrence       of,       in 

blood,  5,  133 
,  occurrence       of,       in 
the   intestine,  296, 
454 
,  occurrence       of,       in 

urine,  459 
,  occurrence       of,       in 
transudations,   190, 
194 
Reduction  proce-sses,   1,  2,  5,   7,  234,  296, 

330,  441,  454,  477 
Reichert-Meis-sl's  equivalent,   97 
Reindeer,  milk  of,  396 
Rennin,  200,  207,  389,  390 

,  detection   of,   in  gastric  contents, 

270 
,  detection  of,  in  the  pancreas,  290 
,  passage  of,  into  urine,  462 
Rennin  cells,  257 
Rennin  glands,  257 
Rennin   zymogen,  257,  267 
Re.sacetophenon,  482 
Reserve  cellulose,  91 
Resin  acids,  transition  into  the  urine,  483, 

485 
Respiration,  external,  530.  536—542 
,  internal,  530.   543 
of  the  hen's  egg,  383 
of  plants,  2 


Respiration.    See  also  Exchange  of  Gas  un- 
der various  conditions. 

Respiratory  quotient,  330,  3.52,  552,  582 

Rest,    metabolism    during.    347,    348. — 352, 
582 

Reticulin,  16,  57,  316 

Retina,  364 

Reversion,  85 

Reynolds'  acetone  reaction,  508 

Rhamnose,  71,  77 

,  relation     to     glycogen     forma- 
tion, 78,  214' 

Rheometer,   540 

Rhodizonic  acid,  341 

Rhodophan,  366 

Rhodopsin,   365 

Rhubarb,  action  on  the  urine,  483,  496 

Rib-cartilage,  320 

Ribose,  78 

Rice,  relation  to  excrements,  307 

Rigor  mortis  of  the  muscles,  346,  347 

Roberts'     method     of     estimating     sugar, 
504 

Rodents,  bile-aeids  of,  231,  240 

Rods  of  the  retina,  pigments  of,  365 

Rosenbach's  bile-pigment  test,  394 
urine  test,  511 

Rovida"s  hvaline  substance,   101,   137,   156, 
197 

Rubner's  sugar  test,  82,  499 

Rye  bread  in  the  intestine,  307,  310 

Saccharic  acid,  72,  460 

,  relation  to  glycogen  forma- 
tion, 214 
Saccharin,  relation   to  glycogen  formation, 

214 
Saccharogen  in  the  mammary  gland,  404 
Saccharose.     See  Cane  Sugar. 
Salicylic   acid,  action  on   pepsin  digestion, 
265 
,  action  on  metabolism,  577 
,  action  on  trypsin  digestion, 

289 
,  behavior     in      the      animal 
body,  480 
Salicyl  aldehyde,  oxidation  of,  6 
Salicyl-sulphonic   acid   as   proteid   reagent, 

26 
Saliva,  249—257 

,  secretion  of,  256,  257 
,  mixed,  252 

,  physiological  importance,  256 
,  behavior  in  the  stomach,  257 
,  various  kinds  of.  250,  251,  252 
,  action  of,  253.  254,  255 
,  composition  of,  255 
Salivary  calculi,  257 
Salivary  diastase.     See  Ptyalin. 
Salivary  glands.  249 
Salkowski's  cholesterin  reaction,  247 
Salkowski-Ludwig's  method  of  estimating 
uric  acid,  434 


INDEX. 


623 


Salniin,  59,  GO,  372 
Salmon,  lU-sli  of,  338 

,  spernia  of,  59,  372 
Salnionueleic-  acid,  108 
Saltpetre,  action  on  metabolism,  577 
Salts.    See  the  various  salts. 
Salt-plasma,  124 
Salts   of   vegetable   acids,   behavior   in   tlie 

organism,  408 
Sanumdarin,  527 

Santonin,  action  on   tiie  urine,  483,  49(3 
Saponification  equivalent,  97 
Saponification  of  neutral  fats,  93,  97,  286, 

292,  310,  311—314 
Sarcolactic  acid.     See   raralactic  acid. 
Sarcolemma,  332 
Sarcomehinin.  524 
Sarcomellanic  acid,  524 
Sarcosin,  339 

,  behavior  in  tiie  animal  body,  47G 
Sarkin.    See  Hypo.vanthin. 
Scherer's  inosit  test,  342 

reaction  for  leuein,  G4 
reaction  for  tyrosin,  05 
Schift's  reaction  for  cholesterin,  247 
reaction  for  uric  acid,  433 
reaction  for  urea,  41G 
Schreiner's  base,  371 
Schweitzer's  reagent,  90 
Sclerotica,  368 
Scombrin.  GO 
Seyllit,  199 
Scymnol,  226 

Scymnol-sulphuric  acid,  226 
Sebacic  acid,  95 
Sebum,  52G 

Secondary  albumoses,  37 
Sedimentation  of  the  blood  corpuscles,  136 
Sediments.     See  Urinary  sediments. 
Sedimentuni  lateritium,  407,  432,  513 
Selivanoflf's  reaction  for  levulose,  83,  505 
Semen,  370 
Semiglutin,  56 
Seminose.    See  Mannose. 
Senna,  action  on  the  urine,  483 
Seralbumin,  16,  130 

,  detection    of.    in    the    urine, 

484—486 
,  quantitative      estimation      of, 

132,  488 
,  absorption  of,  304 
,  behavior  in   ll>e  animal  body, 
131,  380 
Serglobulin,  16,  129 

,  relation  to  the  coagulation  of 

the  blood,  163 
,  detection  of,  in  the  urine,  484 
,  quantitative     estimation     of, 
130,  488 
Sericin,  IG.  58 
Sericoin.  59 
Serin,  59.  130 
Serolin,  131 


Serous  fluids,  185—196 
Serum.     See  Blood-.serum. 
Serum  casein.     See  Serglobulin. 
Se.\,  induence  on  metabolism,  580 
Sharks,  bile  of,  22G 

,  urea  in  bile  of,  238 
Sheep's  milk,  397 

Shell-membrane  of  the  hen's  egg,  51,  381 
Silicic  acid  in  feathers,  521 
in  urine,  472 

in  hen's  egg,  378,  381,  382 
Silicic  acid  ester  in  feathers,  521 
Silk  gelatin,  58 
Sinistrin,  animal,  103 
Sincalin,   103 
Skatol,  22,  294,  295 

,  formation  in  putrefaction,  294,  443, 

449,   450 
,  behavior  in  the  animal   body,  394, 
444,  449,  479,  482 
Skatol-acetic  acid,  22 
Skatol-amido-acetic  acid,  22 
Skatol-carbonic  acid,  450 
Skatol-pigment,  450 
Skatoxyl,  295,  449,  450 
Skatoxyl-glycuronic  acid,  450 
Skatoxyl-sulphuric  acid,  443,  449,  450 
in  sweat,  565 
Skeletins,  58 

Skeleton  at  various  ages,  323 
Skin,  521—530 

,  excretion  through,  525^529 
Sleep,  metabolism,  580 
Smegma  praeputii,  526 
Smith's  reaction  for  bile-pigments,  495 
Snail  mucin,  45 
Snake  poison,  14 
Soaps  in  blood-serum,  132 
in  chyle,  183,  310 
in  pus,  197 
in  excrements,  301 
in  bile,  225,  237 
,  importance  of,  in   the  emulsifieation 
of  fats,  286,  292,  311,  313 
Sodium     alcoholate     as     a     saponification 

agent,  93,  97 
Sodium  butyrate  in  acetonuria,  507 
Sodium  chloride,  elimination  by  the  urine, 
136,  463.  4G4 
,  elimination  bv  the  sweat, 

528 
,  physiological   importance, 

564 
,  quantitative     estimation, 

464,  465 
,  influence  on  the  quantity 

of  urine,  577 
,  influence  on  the  elimina- 
tion of  urea,  577 
,  influence  on  the  secretion 

of  gastric  juice,  268 
,  behavior   with   food    rich 
in  potassium,  564 


624 


INDEX. 


Sodium    chloride,    insufficient    supply    of, 
136,  208,  564 
,  action    on    pepsin    diges- 
tion, 265 
,  action    on    trypsin   diges- 
tion, 288 
Sodium    compounds,    elimination    by    the 
urine,  470 
,  division     among    the 
form-elements  and 
fluids,  121 
.  See  also  the  various 
tissues  and  fluids. 
Sodium  phosphate  in  the  urine,  407,  466, 

467,  513 
Sodium  salicylate,  action  on  the  secretion 

of  bile,  225 
Sodium  sulphate,  taction  on  proteid  meta- 
bolism, 577 
Sodium     tartrate,     relation     to     glycogen 

formation,  214 
Soldiers,  diet  of,  589 
Sorbinose,  83 
Sorbite,  73 

Source  of  muscular  energy,  352,  353 
Sparing  theory,  216 
Specific  rotation,  76 
Spectrophotometry,  153,  154 
Sperma,  59,  370—372 
Spermaceti,  98 
Spermaceti  oil,  98 
Spermatin,  372 
Spermatocele  fluids,  193 
Spermatozoa,  371,  372 
Spermin,   371 
Sperrain  crvstals,  370 
Spherules,  24,  376,  382 
Sphygmogenin,  205 

Spider  excrement,  guanin  therein,  117 
Spider  poison,  14 
Spiegler's  reagent,  486 
Spirographin,  48 
Spirogyra,  121 
Spleen,  199,  200 

,  relation    to    formation    of    blood, 

200 
,  relation  to  formation  of  uric  acid, 

200.  429,  430 
,  relation  to  digestion,  200 
,  blood    of  the,   173 
Spleen  pulp.   199 
Splitting  processes,  1,  2,  9 
Spongin,   16,  58 
Sputum,  544,  545 
Starch,  87 

,  hydrolytic    cleavage   by    intestinal 

juice,  281 
,  hydrolytic   cleavage   by  pancreatic 

juice,  285 
,  hydrolytic  cleavage  by  saliva,  253, 

■^  254 
,  calorific  value  of,  554 


Starch,  absorption  of,  308,  309 

,  behavior  in  the  stomach,  271 
Starch  cellulose,  87 
Starch  granulose,  87 
Starvation,  action  on  the  blood,  175,  180 

,  action  on  the  secretion  of  bile, 

224 
,  action  on  the  urine,  297,  410, 

427,  441,  447 
,  action    on    the    elimination    of 

indican,  297,  447 
,  action    on   the    elimination    of 

oxalic  acid,  438 
,  action     on     the     secretion     of 

pancreatic  juice,  283 
,  action    on    the    elimination    of 

phenol,  297 
,  action     on     metabolism,     553, 

556—562 
,  quantity  of  nitrogen  in  excre- 
ments in,  549 
,  death  from,  556 
Starvation  cures,  590,  591 
Steapsin,  285 
Stearic   acid,   94 
Stearin,  94 

,  absorption  of,  312 
Stercobilin,  234,  302,  455 
Stercorin,  247,  302 
Stethal,  98 

Stokes's  reduction  fluid,   143 
Stokois's  reaction  for  bile-pigments,  495 
Stomach,  importance  in  digestion,  273,  274 
,  relation    to    intestinal    putrefac- 
tion, 275 
,  auto-digestion  of,  274 
,  digestion  in  the,  270 — 275 
Stomachic  glands,  257,  269,  270 
Streptococcus,  behavior  with  gastric  juice^ 

274 
Stroma  fibrin,  138 
Stroma  of  the  blood-corpuscles,  137 

of  the  muscles,  336 
Strontium  salts  and  blood  coagulation,  124 
Struma  cystica,  204 

Strychnin,  passage  of,  into  the  urine,  483 
Sturgeon,  sperma  of,  59,  372 
Sturin,  59 

Sublingual  glands,  249 
Sublingual  saliva,  251 
Submaxillary  glands,  249 
Submaxillary  mucin,  44,  45 
Submaxillary  saliva,  250 
Succinic  acid  in  putrefaction,  20 

in  the  fermentation  of  milk, 

386 
in  the  intestine,  293 
in  the  spleen,  199 
in  transudations,  190,  194 
in  the  thyroid  glands,  201 
,  passage    of,    into    the    urine, 
459 


JMJhX. 


625 


Succinic  acid,   |)a:>sagc  of,   into  the  sweat, 

52S 
8u<;ar.    relation    to    \v(.rk.    348,    349,    352, 
3.">3 
,  formation   from  fats.  218,  3.)3 
,  formation   from   i)e|)tones.  218 
Su^'ar  formation  in  the  liver.  217 — 219,222, 
223 
after      pancreas      extirpa- 
tion. 222,  223 
Sujrar.  behavior  on  subcutaneous  injection, 
21G 
,  beliavior  to   bloo<l-corpuscles,   IGO 
.  .See  also  various  kinds  of  sugar. 
Sugar  tests  in  the  urine.  49G — 504 
Sulphocyanides  in  the  urine.  461 

in  the  saliva.  251,  252 
Sulphonal  intoxication,  urine  in.  492 
Sulphone,    behavior    in    the    animal    body, 

477 
Sulphonic    acids,    behavior    in    the    animal 

body,   477 
Sulphur  of  proteids.  18 

in  the  urine.  401,  4G2 
,  elimination    of,    in    activity,    351. 

4G1,  4G2 
,  elimination   of,  with   lack   of  oxy- 
gen. 4G1,  4G2 
,  neutral      and      acid      sulphur      in 

urine.  4G1 
.  behavior  in  the  organism,  4G1,4G2 
Sulphur  methivmoglobin,  146 
Sulpliuretted   hydrogen   in   putrefaction   in 

the  intestine. "294.  29G 
Sulphuretted  hydrogen  in  the  urine,  462 
Sulphuric  acid,  ethereal,  and  sulphate  in  the 
urine.  4G9 
,  elimination  of,   in   activity. 

351 
,  elimination      of,      by      the 

urine,  469 
,  elimination      of,      by      the 

sweat,  528,  529 
,  estimation  of.  469 
,  relation    to    elimination    of 

nitrogen,  351,  4G9,  549 
,  action  on  pepsin  digestion, 
264 
Suprarenal  capsule,  204 
Sweat,  527—529 

,  secretion  of,  527 
,  action  of,  on  the  urine.  407,  408 
Swimming-bladders  of  fishes,  gases  of,  543 
,  guanin  in,  117 
Sympathetic  saliva.  250 
Synovial    fluid,   195 
Synovin,   195 
Synthesis.  1.  2,  G 

of  etliereal  sulphuric  acids,  294, 

443,  447.  449,  482 
of  proteid,  24 

of   cnnjuirated    trlvfurnnic   acids. 
445.  449.  460.  477.  4S2 


Synthe^s  of  uric  acid,  426,  429 
of  urea,  410,  413,  414 
of  hip|)uric  acid,  2,  440 
of    varieties    of    sugars,    73,    74, 
79 
Syntonin,   32,  336 

,  calorific  value  of,  555 

Tagatose,  75 

Talonic  acid,  84 

Talose,  75,  84 

Tapeworm  cyst,   195 

Tannic  acid,  behavior  in  the  animal  body, 

482 
Tartar,  257 

Tartaric  acid,  rehition  to  glycogen  forma- 
tion. 214 
,  passage  of,  into  sweat,  528 
,  behavior  in  the  animal  body, 
476 
Tatalbumin,  379 
Taurin,  232 

.  behavior  in  'the  animal  body,  476 
Tauro-carbamic  acid,  476 
Taurocholic  acid.  228 

,  (|uantitv  in  various  biles, 

239,  "240 
,  occurrence   in   meconium, 

302 
,  decomposition   in   the   in- 
testine,   297 
,  proteid    precipitating   ac- 
tion, 26 
Tea,  action  on  metabolism,  578 
Tears.  36S 
Teeth,  325 

Teichmann's  crystals.   149.   150,  491 
Tendon   mucin.  45,  316 
Tendon  synovia,  195 

Tension  of  the  CO,  in  the  blood.  539—543 
in  the  tissues,  543 
in  the  lymph.  184 
Oin  the  blood.  536—541 
Terpen-glycuronic  acid,  482 
Terpentine,  acticm  of.  on   the  secretion  of 
bile,  225 
,  action    of.   on    the    urine,   482, 

483 
,  behavior   in   the   animal   body, 
482 
Tetanin,  13 

Tetronerythrin,  154.  525 
Testis.  3*70 
Tewfikose,  392 

Thallin.  action  on  the  urine,  483 
Theobromin,  115 

,  behavior  in  the  animal  body, 
436 
Theophyllin,   115 

,  behavior  in  the  animal  bodv, 
436 
Th'fiilcokols,  behavior  in  the  animal  body, 
477 


e-26 


JM>EX 


Tliioglvcolic  aeid,  behavior  in  the  animal 
bod}%  477 

Thiohic'tic  acid,  52 

Thiophen,  481 

Thiophenic  acid,  481 

Thiophenuiie  acid,  481 

Thrombin,  127,  128,  162—165 

Thrombosin,  1G5 

Thymin,  110 

Thymic   acid^   110 

Thymus,  200 

,  relation    to    the    elimination    of 
allantoin,  440 

Thymus-nucleic  acid,  109 

Thyreoantitoxin,  202 

Tlivreoglobulin,   203 

Thyreoproteid,  202 

Thvreoproteine,   201 

Thyroid  gland,  201,  202 

,  relation    to    proteid    eata- 
bolism,  202 

Thyroiodin.     See  lodothyrin. 

Tissue-fibrinogen,  101,  1*12,   166 

Tollen's  reaction  for  pentoses,  506 

Toluhydrochinon,  451 

Toluol,  behavior  in  the  animal  body,  441, 
470 

Toluric  acid,  480 

Toluvlendiamin,  poisoning  with,  244 

Toluylic  acid,  480 

Tonus,  chemical,  of  the  muscle,  347 

Tooth  tissue,  325 

Tortoise,   bones  of,  322 

Tortoise-shell,  51,  526 

Toxalbumins,  14 

,  relation   to   the   coagulation 
of  the  blood,  161 

Toxins,  13,  206 

Transudations,  188—198,  536 

Trehalose,  87 

Tribromacetic   acid,  22 

Triliroinamido-benzoic   acid,  22 

Tricahiuin  casein,  389 

Tricliloracetic  acid  as  reagent,  26 

Trichlorbutyl  alcohol,  behavior  in  the  ani- 
mal body,  477 

Trclilorbutyi-glycuronic  acid,  477 

Tricliloretliyl-glycuronic  acid.     See  Uroch- 
loralic  acid. 

Trichlorpurin,  114 

Trinitro  albumin,  22 

Triolein.  95 

Tri|)alinitin,  94 

Triple  phosphate  in  urinary  sediments,  514, 
516 
in    urinary     calculi,    510, 
518 

Tristearin,  94 

Trommer's  test  for  sugar,  81,  497 

T  rommor's    test   for   sugar,   behavior   with 
glycuronic  acid,  401 

Trommer's   test  for   sugar,   behavior   with 
uric  acid,  433 


Trommer's  test   for   sugar,  behavior   with 

ceratinin,  423 
Tropics,  metabolism  in  inhabitants  of,  584 
Trypsin,  282,  287 

,  action  on  proteids,  288 
,  action  on  other  substances,  290 
Trypsin  digestion,  288 

,  action  of  various  condi- 
tions upon,  288,  289 
,  products  of,  289 
Trypsin  zymogen,  287,  290 
Tryptophan,  20,  289 
Tuberculinic  acid,  59 
Tuberculosamin,  59 
Tubo-ovarial  cysts,  375 
Tunicin,   521,  522 
Turacin,  525 
Turacoverdin,  525 
Typhotoxin,  13 
Tyrosin,  64 

,  in  urine,  511 

,  in  sediments,  511,  516 

,  detection  of,  65,  511 

,  origin  of,  19,  20,  64,  294 

,  behavior     in     putrefaction,     294^ 

441,  443 
,  behavior  in  the  animal  body,  478,. 
479 
Tyrosin-sulphuric  acid,  65 

Uft'elmann's  reaction  for  lactic  axu4;  277 
Ultzmann's  test  for  bile-pigments,  495 
Uraemia,  bile  in,  240 

,  gastric   contents  in,  276 
,  sweat  in,  528 
Uramido  acids,  476 
Uramido-benzoic  acid,  480 
Urates,  432 

in  sediments,  406,  514,  515 
Urea,  410 

,  elimination  in  starvation,  410,  558 
,  elimination  in  children,  411,  580 
,  elimination  in  disease,  411,  415,  471 
,  elimination  after  various  foods,  410,. 

566,  567,  568,  570—576.  577 
,  progress  of  elimination  after  meals,. 

570 
.,  properties  and  reactions,  415 — 417 
,  formation  and  origin,  412 — 415,  470, 

471 
,  quantitative  estimation,  417 — 422 
,  s])litting  by  ferments,   10,  416,  514 
,  synthesis,  410,  412—415 
,  occurrence    in    the   blood,    134,    172,. 

179,  414,  415 
,  occurrence  in  the  bile,  238,  410 
,  occurrence    in    the    vitreous    humor, 

366 
,  occurrence  in  the  liver,  410,  431 
,  occurrence  in  the  mu.scles,  338 
Urea  nitrate,  416 
Urea  oxalate,  416 
Ureids,  18,  426,  430 


INDEX. 


mi 


Ureomcter,  Esbach's,  422 

Urethan.     See   Carbaniic   acid   ethyl-ester, 

422 
Uric  acid,  42ti 

,  elimination  in  disease,  427,  428 
,  elimination    after    feeding    with 

niulein,  42'J 
,  relation  to  nrea,  42(5,  431 
,  properties   and   reactions,   431 — 

433 
,  formation    in    the   animal   bodv, 

428—431 
,  formation  from  ammonia,  428 
,  relation  to  leucocytosis,  430 
,  relation  to  the  spleen,  200,  429, 

430 
,  quantitative    estimation,    433 — 

435 
,  syntheses  of,  420 
,  behavior    in    the    animal    body, 

431 
,  occurrence   of,   426 
,  occurrence   of,   in    the   blood   in 

pneumonia,   179 
,  occurfence  of,  in  butterflies,  427, 

525 
,  occurrence  of,  in  sweat,  529 
,  occurrence  of,  in  sediments,  406, 
432,  513,  514 
Uric-acid  calculi,  517 
V'ricacida?mia,   17!) 
Urinary  calculi,  510 — 520 
Urinary  pigments,  453 — 459,  493 
,  medicinal,  496 
Urinary  sand,  510 
Urinary  sediments,  406,  514 — 516 
Urine,  405 — 521 

,  excretion  of,  473 

,  inorganic  constituents  of,  403 — 473 

,  poisonous  constituents  of,  403 

,  organic  pathological  constituents  of, 

483—513 
,  physiological  constituents  of,  410 — 

473 
,  casual  constituents  of,  475 — 483 
,  color  of,  407,  453,  475,  483,  490,  492, 

494,  490 
,  solids,  calculation  of,  474 
,  quantity  of  solids.  475 
,  alkaline   fermentation   of,   410,   459, 

514 
,  acid  fermentation  of,  513 
,  gases  of,  473 
,  quantity  of,  473 — 475 
,  physical  properties  of.  400 — 410 
,  reaction  of,  407,  408,  513 
,  acidity  of,  407,  408 
,  estimation  of  acidity,  408.  408 
,  specific  gravity  of,  408,  409 
,  determination    of    specific    gravity, 

409.  474,  475 
,  passage  of  foreign  bodies  into,  475 — 
483 


Urine,  reducing  power  of,  459 
,  composition  of,  475 

Urine   indican,  447 

Urine  indigo,  447,  449,  453,  511,  510 

Urine  poison,  403 

Urine  sugar.     See  Dextrose. 

Urinometer,  409 

Urobilin,  453,  454—458 

,  relation    to    bilirubin,    234,    243, 

454,  455 
,  relation  to  choletelin,  453 
,  relation  to  hajmatin,  243,  455 
,  relation      to      haematoporphyrin, 

151,  455 
,  relation  to  hydrobilirubin,234,  454 

Urobilin   icterus,  450 

Urobilinogen,  453,  457 

Urobilinoid   bodies,  454 

Urobilinoidin,  454 

Urocarnic  acid,  403 

Urochloralic  acid,  40O,  477 

Urochrome,  453,  454 

Urocyanin,   453 

Uroerythrin,  453,  458 

UrofuscohaMuatin,  493 

Uroglaucin,  453 

Urohaematin.  453 

Urohodin,   453 

Uroleucic  acid,  440,  450,  452 

Uramelanins,  453 

Uroiiitro-toluolic  acid,  482 

Uropha'in,  453 

Urorubin.  453 

Urorubrohaematin,   493 

Urorosein,  453,  493 

Urospectrin,  492 

Urostealith.  518 

Urotoxic  coelHcient,  403 

Uroxanthin.  44/ 

Uroxonic  acid.  420 

Uterine  milk.  383 

Valerianic  acid,  18,  23 

Vegetable    acids,    behavior    of    the    alkali 

salts  of,  in  body,  408,  476 
Vegetable  gums,  88,  90 
Vegetable  mucilages,  88,  90 
Vegetable  mjosin,  43 
Vegetable  protcid.  43 
Vegetarians,  food  of,  573,  580 

,  excrement  from,  300 
Vernix  caseosa,  520 
A'esicatory    blisters,    195 
Visual  purple.  305 
Visual   red.  305 
A'itali's  pus-blood  test,  491 
Vitellin,   10 

in  yolk  of  egg,  376 

in  protoplasm,   101 
Vitellolutein,  378 
Vitellorubin.  378 
Vitelloses.   .30 
Vitreous  humor,  366 


628 


INDEX. 


Water,  drinking  of,  action  in  the  elimina- 
tion    of     chlorides, 
4G4 
,  action  on  the  elimina- 
tion   of    uric    ac'  ', 
428 
,  action  on  the  elimina- 
tion of  urea,  576 
,  action   on   the   deposi- 
tion of  fat,  576 
,  action    on    the    excre- 
tion   of   urine,   473, 
474 
Water,  elimination  of,  by  the  urine,  473 — 
475,  548 
,  elimination   of,   by    the   skin,   527, 

548 
,  elimination  of,  in  starvation,  560 
,  elimination  of,  importance  for  the 

animal  body,  562 
,  elimination  of,  quantity  of,  in  the 

various  organs,  562 
,  elimination,   lack   of,   in   the  food, 
562 
Wax  in  plants,  98,  526 
Weidel's  xanthin  reaction,  117 
WeyFs  reaction  for  creatinin,  424 
Wheat  bread,  absorption  of,  307 
Wliey,    387 
Wliey  proteid,  390 
Wliite  of  (igg,  378 

,  calorific  value  of,  554 
Witch's  milk,  401 
Woman's  milk.     See  Human  milk. 
Wool-fat,   248,   527 

Work,  action  on  the  elimination  of  chlorine, 
464 
,  action  on  the  elimination  of  phos- 
phoric acid,  467 


Work,   action   on    the   elimination   of  sul- 
phur, 351,  461 
,  action    on    the    necessity   for   food, 

588—590 
,  action     on     metabolism,     548 — 552, 
579—583 
Worm-Miiller's  sugar  test,  497 
Xanthin,  115,  116 

in  the  urine,  435 
in  urinary  calculi,  518 
,  in  urinary  sediments,  516 
J  detection   and   quantitative    esti- 
mation, 120,  121,  437 
Xanthin  bodies.     See  Nuclein  bases. 
Xanthin  calculi,  518 
Xantho-creatinin,  341,  350,  425 
Xanthophan,  366 
Xanthoproteic  acid,  22 
Xanthoproteic  reaction,  27 
Xanthorharanin,  78 

Xylol,  behavior  in  the  animal  body,  479 
Xyloses,  78,  91 

,  relation     to     the     formation     of 
glycogen,  77,  214 

Yeast-cells,  relation  to  fermentation,  9,  10 
Yeast  nucleic  acid,  109 
Yolk  of  the  hen's  egg,  376 
Yolk-spherules,  376,  382 

Zinc  in  the  bile,  238 
in  the  liver,  211 
,  passage  of,  into  milk,  404 
Zooerythrin,  525 
Zoofulvin,  525 
Zoorubin,  525 

Zymase  from  beer-yeast,  10 
Zymogens.    See  various  enzymes. 
Zymoplastic  substances,  163,  165,  166 


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"Wait's  Engineering  and  Architectural  Jurisprudence Svo,  6  00 

Sheep,  6  50 
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tecture  12mo,  125 

*  World's  Columbian  E.xposition  of  1893 Large  4to,  1  00 

ARMY,  NAVY,  Etc.  -^ 

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*  Davis's  Treatise  on  Military  Law Svo, 

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Large  12mo,       2  00 

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2 


6 

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1  50 

10 

2  50 

4  00 

1  50 

2  00 

2  50 

1  50 

2  00 

1  00 

Hofif's  Naval  Tactics 8vo, 

*  Ingalls's  Ballistic  Tables 8vo. 

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WoodbuH's  Notes  on  Military  Hygiene 16mo, 

Young's  Simple  Elements  of  Navigation 16mo,  morocco, 

"  "  "         "  "  first  edition 

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3 


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Thome's  Structural  Botany 16mo,  2  25 

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BRIDGES,  ROOFS,   Etc. 

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{See  also  Engineering,  p.  7.) 

Boiler's  Highway  Bridges 8vo,  2  00 

*  "       The  Thames  River  Bridge 4to,  paper,  5  00 

Burr's  Stresses  lu  Bridges. Bvo,  3  50 

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Greene's  Arches  iu  Wood,  etc Bvo,  2  50 

Bridge  Trusses Bvo,  2  50 

'  •         Hoof  Trusses Bvo,  1  25 

Howe's  Treatise  on  Arches Bvo,  4_Q0 

Johnson's  Modern  Framed  Structures Small  4to,  10  00 

jlerrimau    &    Jacoby's    Text-book    of    Roofs     and    Bridges. 

Part  L,  Stresses Bvo,  2  50 

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Part  II.,.  Graphic  Statics  Bvo,  2  50 

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*  Morison's  The  Memphis  Bridge Oblong  4to,  10  00 

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16mo,  morocco,  3  00 

"        Specifications  for  Steel  Bridges 12mo,  1  25 

Wood's  Construction  of  Bridges  and  Roofs Bvo,  2  00 

Wright's  Designing  of  Draw  Spans.     Parts  I.  and  II.. Bvo,  each  2  50 

"               "          "      "           "          Complete Bvo,  3  50 

4 


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Adriance's  Laboratory  Calculations 12m<>, 

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Austen's  Notes  for  Chemical  Students 12nu), 

Bolton's  Student's  Guide  in  Quantitative  Analysis .8vo, 

Bollvvood's  Elementary  Electro  Chemistry {In  the  press.) 

Classen's  Analysis  by  Electrolysis.  (Ilerrick  and  BoUwood.).&vo, 

Cohn's  Indicators  and  Test-papers 12nio 

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logical Variations 12mo,  morocco, 

Drechsel's  Chemical  Reactions.    (Merrill.) 12mo, 

Erdmaiin's  Introduction  "to  Chemical  Preparations.     (Dunlap.) 

12uu), 

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"  Qualitative  "  "  (Johnson.) 8vo, 

(Wells.)         Trans. 

16th  German  Edition 8vo, 

Fuertes's  "Water  and  Public  Health 12nio, 

Gill's  Gas  and  Fuel  Analj-sis 12mo, 

Hammarsten's  Physiological  Chemistry.    (Maudel.) 8vo, 

Helm's  Principles  of  Mathematical  Chemistry.    (Morgan).  12mo, 

Hopkins'  Oil-Chemist's  Hand-book 8vo, 

Ladd's  Quantitative  Chemical  Analysis 12mo, 

Landauer's  Spectrum  Analysis.     (Tingle.) 8vo, 

Lob's  Electrolysis  and  Electrosyn thesis  of  Organic  Compound?. 

(Lorenz.) , 12mo, 

Mf  ndel's  Bio-chemical  Laboratory 12mo, 

Mason's  Water-supply 8vo, 

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Meyer's  Radicles  in  Carbon  Compounds.  (Tingle.) 12mo, 

Mi.\ter's  Elementary  Text-book  of  Chemistry 12mo, 

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"         Elements  of  Physical  Chemistr}' 12mo, 

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Poole's  Calorific  Power  of  Fuels 8vo, 

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"         and  Woodman's  Air,  Water,  and  Food 8vo, 

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metallic)  01)long  8vo.  morocco. 

Rideal's  Sewage  and  the  Bacterial  Purification  of  Sewage... 8vo, 

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Riuldiman's  Incompatibilities  in  Prescriptions 8vo,    $3  00 

Schimpf's  Volumetric  Analysis 12mo, 

Spencer's  Sugar  Manufacturer's  Handbook 16mo,  morocco, 

*'  Handbook    for    Chemists    of  Beet    Sugar    Houses. 

16mo,  morocco, 

Stockbridge's  Rocks  and  Soils 8vo, 

*  Tillman's  Descriptive  General  Chemistry 8vo, 

Van  Deventer's  Physical  Chemistry  for  Beginners.    (Boltwood.) 

12mo, 

Wells's  Inorganic  Qualitative  Analysis 12mo, 

"      Laboratory   Guide   in   Qualitative   Chemical  Analysis, 

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Whipple's  Microscopy  of  Drinking-water Svo, 

Wiechmanu's  Chemical  Lecture  Notes 12mo, 

"  Sugar  Analysis , Small  Svo, 

WuUing's  Inorganic  Phar.  and  Med.  Chemistry. 12mo, 


DRAWING. 

Elementary — Geometrical — Mechanical — Topographical. 

Hill's  Shades  and  Shadows  and  Perspective Svo, 

MacCord's  Descriptive  Geometry Svo, 

"  Kinematics Svo, 

"  Mechanical  Drawing Svo, 

Mahan's  Industrial  Drawing.    (Thompson.) 2  vols.,  Svo, 

Reed's  Topographical  Drawing.     (H.  A.) 4to, 

Reid's  A  Course  in  Mechanical  Drawing Svo. 

"      Mechanical  Drawing  and  Elementary  Machine   Design. 

Svo, 

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Warren's  Descriptive  Geometry 2  vols.,  Svo, 

"         Drafting  Instruments 12mo, 

' '         Free-hand  Drawing 12mo, 

"        Linear  Perspective 12mo, 

"        Machine  Construction 2  vols.,  Svo, 

"        Plane  Problems 12mo, 

"        Primary  Geometry 12mo, 

"        Problems  and  Theorems Svo, 

"        Projection  Drawing 12mo, 

"        Shades  and  Siiadows Svo, 

"        Stereotomy— Si  one-cutting Svo, 

Whelpley's  Letter  Engraving 12mo, 

Wilson's  Free-hand  Penspeclive Svo, 

6 


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2  50 

ELECTRICITY  AND  MAGNETISM. 

Ili.c.mination—Batteuies— Physics  -Kailwayb. 

Anthouy  auil  Brackctt's  Text- book  of  Physics.     (Magic.)   Small 

8vo,  $3  00 

Aiillioiiy's  Theory  of  Electrical  Measuremeuls 12mo,  1  00 

Barker's  Deep  sea  Souucliugs bvo,  2  00 

Benjamin's  Voltaic  Cell 8vo,  'd  00 

History  of  Electricity 8vo,  3  00 

Classen's  Analysis  by  Electrolysis.    iHeriick  and  Bollwood  )  8vo,  3  00 
Crehore  and  Squier's  Experiments  with  a  New  Polarizing  Photo- 
Chronograph 8vo,  3  00 

Dawson's  Electric  Railways  and  Tramways.     Small,  4lo,  half 

morocco,  12  50 

*  "Engineering"  and  Electric  Traction  Pocket-book.      16mo, 

morocco,  5  00 

*  Dredge's  Electric  Illuminations. .  .  .2  vols.,  4to,  half  morocco,  25  00 

Vol.  II 4to,  7  50 

Gilbert's  De  magnete.     (Mottelay.) 8vo,  2  50 

Holman's  Precision  of  Measurements 8vo,  2  00 

"         Tekscope-mirror-scale  Method Large  8vo,  75 

Lob's  Electrolysis  and  Electrosynthesis  of  Organic  Compounds. 

(Lorenz.) 12mo,  1  00 

*Michie's  Wave  Motion  Relating  to  Sound  and  Light 8vo,  4  00 

Morgan's  The  Theory  of  Solutions  and  its  Results 12mo,  1  00 

Niaudel's  Electric  Batteries      (Fi.«hback.) 12mo,  2  50 

*Parsliall  &  Ilobart  Electric  Generators.     Small  4to,  half  mor.,  10  00 

Pratt  and  Alden's  Street-railway  Road-beds 8vo,  2  00 

Reagan's  Steam  and  Electric  Locomotives 12mo,  2  00 

Thurston's  Stationary  Steam  Engines  for  Electric  Lighting  Pur- 
poses  8vo,  2  50 

♦Tillman's  Heat 8vo,  1  50 

Tory  &  Pitcher's  Laboratory  Physics ...  .(In  press) 

ENGINEERING. 

Civil — Mechanical — Saxitaky,  Etc. 

{See  also  Bridges,  p.  4 ;  Hyduaulics.  p.  9 ;  Materials  of  En- 
gineering, p.  10 ;  Mechanics  and  Machinery,  p.  12  ;  Steam 
Engines  and  Boilers,  p.  14.) 

Baker's  Masonry  Construction .8vo,  5  00 

"        Surveying  Instruments 12mo,  3  00 

Black's  U.  S.  Public  "Works Oblong  4to,  5  00 

Brooks's  Street-railway  Location 16mo,  morocco,  1  50 

Butts's  Civil  Engineers'  Field  Book 16mo,  morocco,  2  50 

Byrne's  Highway  Construction 8vo,  5  00 

7 


Byrne's  Inspection  of  Materials  and  Woikmausbip IGmo, 

Carpenter's  Experimental  Engineering  8vo, 

Churcb's  Mechanics  of  Engineering — Solids  and  Fluids  —  8vo, 

"        Notes  and  Examples  in  Mechanics 8vo, 

Crandall's  Earthwork  Tables 8vo, 

' '  The  Transiliou  Curve 16mo,  morocco, 

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half  morocco,  $10;  paper, 

*  Drinker's  Tunnelling 4to,  half  morocco, 

Eissler's  Explosives — Nitroglycerine  and  Dynamite 8vo, 

Frizell's  Water  Power 8vo, 

Folwell's  Sewerage 8vo, 

"        Water-supply  Engineering 8vo, 

Fowler's  Coffer-dam  Process  for  Piers . .  8vo. 

Gerhard's  Sanitary  House  Inspection .12mo, 

Godwin's  Piailroad  Engineer's  Field-book 16mo,  morocco, 

Gore's  Elements  of  Geodesy : Svo, 

Howard's  Transition  Curve  Field-book 16mo,  morocco, 

Howe's  Retaining  Walls  (New  Edition.) 13mo, 

Hudson's  Excavation  Tables.     Vol.  II Svo, 

Hutton's  Mechanical  Engineering  of  Power  Plants 8vo, 

"         Heat  and  Heat  Engines 8vo, 

Johnson's  Materials  of  Construction Large  Svo, 

"         Theory  and  Practice  of  Surveying Small  Svo, 

Kent's  Mechanical  Engineer's  Pocket-book 16mo,  morocco, 

Kiersted's  Sewage  Dispo.sal 12mo, 

Mahan's  Civil  Engineering.      (Wood.) Svo, 

Merriuian  and  Brook's  Handbook  for  Surveyors.  .  .  .16mo,  mor., 

Merriman's  Precise  Surveying  and  Geodesy Svo, 

"  Sanitar}'  Engineering Svo, 

Nagle's  Manual  for  Railroad  Engineers 16mo,  morocco, 

Ogdeu's  Sewer  Design 12mo, 

Patton's  Civil.Eugiueering Svo,  half  morocco, 

Patton's  Foundations Svo, 

Philbrick's  Field  Manual  for  Engineers 16mo,  morocco, 

Pratt  and  Alden's  Street-railway  Road-beds Svo,       2  00 

Rockwell's  Roads  and  Pavements  in  France 12mo,       1  25 

Schuyler's  Reservoirs  for  Irrigation Large  Svo.     (7n  press.) 

Searles's  Field  Engineering , 16mo,  morocco,       3  00 

Railroad  Spiral 16mo,  morocco,       1  50 

Siebert  and  Biggin's  Modern  Stone  Cutting  and  Masonry. .  .Svo,       1  50 

Smart's  Engineering  Laboratory  Practice 12mo,       2  50 

Smith's  Wire  Manufacture  and  Uses Small  4to,       3  00 

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"         Hydraulic  Cement 12mo,       2  00 

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3  00 

2  00 

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5  00 

3  00 

Tivylor's  Prismoidal  Fornmlas  iiiul  Eiirthv.ork dvo, 

Tluiisloii's  Maltriiils  of  Const  ruction  8vo, 

Tillson's  Street  Ptivomeiits  aud  Piivinij  Matciials 8vo, 

*  'I'rautwine's  Civil  Engineer's  Pocket-book   .  .  .IGnio,  morocco, 

*  "  Cross-section Sheet, 

*  "  Excavations  and  Embankments Svo, 

*  "  Layintr  Out  Curves 12mo,  morocco, 

Wrtddcirs  De  Poniil)US  (A  Pocket-book  for  Bridge  Engineers). 

ICmo,  morocco. 

Wait's  Engineering  and  Archilectural  Jurisprudence 8vo, 

Slieep, 

"      Law  of  Field  Operation  in  Engineering,  etc Svo. 

*  Sheep, 

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Webb's  Engineering  Instruments.  New  Edition.  16mo,  morocco, 

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Wheeler's  Civil  Engineering 8vo, 

Wilson's  Topograpliical  Surveying ^ Svo, 

Wolll's  Windmill  as  a  Prime  Mover ,. Svo, 

HYDRAULICS. 

Watku-aviikki.s— WixuM I r.t.s— Service  Pipe — Dkai.nage,  Etc 
(See  aUo  Engineering,  p.  7.) 
Ba/.in's  Experiments  u\wu  the  Contraction  of  tbe  Liquid  Vein. 

(Trautwine. ) Svo, 

Bovey 's  Treatise  on  Hydraulics Svo, 

Collin's  Graphical  Solution  of  Hydraulic  Problems I'Jmo, 

Ferrel's  Treatise  on  the  Winds,  Cyclones,  and  Tornadoes. .  .Svo, 

Folwcll's  Water  Supply  Engineering Svo, 

Fuertes's  Water  aud  Public  Health 12mo, 

Ganguillel  ifc  Kulter's  Flow  of  Water.     (Hering  &  Tniulwine  ) 

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Herschel's  115  Experiments  Svo, 

Kiersted's  Sewage  Disposal l'2mo, 

Mason's  Water  Supply Svo, 

"     Examination  of  Water I'imo, 

Merriman's  Treatise  on  Hydraulics Svo, 

Nichols's  Water  Supply  (Chemical  and  Sanitary) Svo, 

Turneaure  and  Russell's  Water-supjily   (///  preit.) 

Wegmann's  Water  Supply  of  the  City  of  New  York 4to, 

Weisbach's  Hydraulics.     (Du  Bois.) Svo, 

Whipple's  Microscoin-  of  Drinking  Water Svo, 

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1  25 

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3  50 

Wilsou's  Irrigation  Engineeviug. 8vo,  $4  00 

Hydraulic  and  Placer  Miuiug 12mo,  3  00 

Wolff's  AVindniill  as  a  Prime  Mover 8vo,  3  00 

Wood's  Theory  of  Turbines 8vo,  2  50 

LAW. 

Architecture — Engineering— Military. 

Davis's  Elements  of  Law Svo,  2  50 

' '      Treatise  on  Military  Law. Svo,  7  00 

Sheep,  7  50 

Murray's  A  Manual  for  Courts-martial 16mo,  morocco,  1  50 

Wail's  Engineering  and  Architectural  Jurisprudence Svo,  6  00 

Sheep,  6  50 

"      Laws  of  Field  Operation  in  Engineering Svo,  5  00 

Sheep,  5  50 

Winthrop's  Abridgment  of  Military  Law ,12mo,  2  50 

MANUFACTURES. 

Boilers— Explosives— Iron— Steel  —Sugar — Woollens,  Etc. 

Allen's  Tables  for  Iron  Analysis Svo,  3  00 

Beaumont's  Woollen  and  Worsted  Manufacture 12mo,  1  50 

Bollaud's  Encyclopaedia  of  Founding  Terms 12mo,  3  00 

The  Iron  Founder 12mo,  2  50 

"          "       "          "        Supplement 12mo,  2-50^ 

Bouvicr's  Handbook  on  Oil  Painting 12nio,  2  00 

Eissler's  Explosives,  Nitroglycerine  and  Dynamite Svo,  4  00 

Ford's  Boiler  Making  for  Boiler  Makers ISmo,  1  00 

Metcalfe's  Cost  of  Manufactures Svo,  5  00 

Melcalf 's  Steel— A  Manual  for  Steel  Users 12mo,  2  00 

*  lieisig's  Guide  to  Piece  Dyeing Svo,  25  00 

Spencer's  Sugar  Manufacturer's  Handbook  . .  .  .16uio,  morocco,  2  00 
"        Handbook    for    Chemists    of    Beet    Sugar    Houses. 

IGmo,  morocco,  3  00 

Tliurston's  Manual  of  Steam  Boilers Svo,  5  00 

Walke's  Lectures  on  Explosives Svo,  4  00 

West's  American  Foundry  Practice 12mo,  2  50 

j\Ioulder"s  Text-book     12mo,  2  50 

Wiechmann's  Sugar  Ana]3^sis Small  Svo,  2  50 

Woodbury's  Fire  Protection  of  Mills Svo,  2  50 

MATERIALS  OF  ENGINEERING. 

Strength — Elasticity — Kesistance,  Etc. 
{See  also  Engineering,  p.  7.) 

Baker's  Masonry  Construction Svo,  5  00 

Beardslee  and  Kent's  Strength  of  Wrouglit  Iron. Svo,  1  50 

10 


7  60 

|5  00 

5  00 

6  00 

10  00 

6  00 

7  50 

7  50 

5  00 

4  00 

1  00 

5  00 

1  2:> 

2  00 

5  00 

8  00 

2  00 

3  50 

•:  50 

3  00 

Bovey's  Strength  of  Maitriuls 8vo, 

Burr's  Elasticity  and  Resistance  of  Materials Bvo, 

Byrne's  IIig,hway  Construction Bvo, 

Church's  Mechanics  of  Engineering — Solids  and  Fluids 8vo, 

Du  Bois's  Stresses  in  P'ranicd  Structures Small  4lo, 

Johnson's  Materials  of  Construction 8vo. 

Lanza's  Applied  Mechanics 8vo, 

^lartens's  Testing  Materials.     (Ileniiing.) 2  vols.,  8vo, 

^lerrill's  Stones  for  Building  and  Decoration 8vo, 

Merriinan's  Mechanics  of  Materials Bvo, 

"  Strength  of  Materials 12nio, 

Patton's  Treatise  on  Foundations Svo, 

Rockwell's  Roads  and  Pavements  in  France 12mo, 

Spalding's  Roads  and  Pavements 12mo, 

Thurston's  Materials  of  Construction 8vo, 

Materials  of  Engineering 3  vols.,  Bvo, 

Vol.  I  ,  Non-metallic Bvo, 

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"Wood's  Resistance  of  Materials Svo, 

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Calculus— Geo.metky — Tkigonometrt,  Etc. 

Baker's  Elliptic  Functions Bvo, 

♦Bass's  Differential  Calculus rjmo, 

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Chapman's  Theory  of  Equations 12mo, 

Compton's  Logarithmic  Computations 12mo, 

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Halsted's  Elements  of  Geometry 8vo, 

"       Synthetic  Geometry Bvo, 

Johnson's  Curve  Tracing 12mo, 

"         Differential  Equations — Ordinary  and  Partial. 

Small  Bvo, 
Integral  Calculus 12mo, 

"  "  "         Unabridged.     Small  Bvo.    {In  press.) 

"        Least  Squares 12mo, 

♦Ludlow's  Logarithmic  and  Other  Tables.     (Bass.) Bvo, 

*       "        Trigonometry  with  Tables.     (Bass.) 8vo, 

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Merriman's  Method  of  Least  Squares 8vo, 

Rice  and  Johnson's  Differential  and  Integral  Calculus, 

2  vols,  in  1,  small  8vo,       2  50 
11 


1 

50 

4  00 

1 

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1 

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1 

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1 

50 

1 

75 

1 

50 

1 

00 

3 

50 

1 

50 

1 

50 

2 

00 

800 

1 

50 

5  00 

2 

00 

Rice  ii^d  Johnsou's  Differential  Ciilculus Small  8vo,  $3  00 

"  Abridgmeut  of  Differential  Calculus. 

Small  8vo,  1  50 

Totten's  Metrology 8vo,  2  50 

Warren's  Descriptive  Geometry 3  vols.,  Svo,  3  50 

"        Drafting  Instruments 12mo,  125 

"        Free-band  Drawing 12mo,  1  00 

''        Linear  Perspective 12mo,  1  00 

"        Primary  Geometry 12mo,  75 

"        Plane  Problems 12mo,  1  25 

"        Problems  and  Theorems Svo,  2  50 

"        Projection  Drawing 12mo,  1  50 

Wood's  Co-ordinate  Geometry .Svo,  2  00 

Trigonometry 12mo,  1  00 

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MECHANICS-MACHINERY. 

Text-books  akd  Practical  Works. 
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Baldvfin's  Steam  Heating  for  Buildings 12mo,  2  50 

JJarr's  Kinematics  of  Machinery Svo,  2  50 

Benjamin's  Wrinkles  and  Recipes .12mo,  2  00 

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Cromwell's  Belts  ami  Pulleys 12mo,  1  50 

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Dana's  Elementary  Mechanics 12mo,  1  50 

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Du  Bois's  Mechanics.     Vol.  I.,  Kinematics  Svo,  3  50 

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Jones's  Machine  Design.     Part  I.,  Kinematics Svo,  1  50 

12 


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7  50 

5  00 

4  00 

5  00 

4  00 

1  50 

3  00 

5i  00 

3  00 

1  00 

7  50 

5  00 

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Machine  Parts 8vo, 

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MiicCord's  Kinematics 8vo, 

^lerrinian's  Mechanics  of  Materials 8vo, 

Metcalfe's  Cost  of  Manufactures 8vo, 

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Ricliards's  Compressed  Air 12mo, 

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Sec.  L     (Klein.) 8vo,       5  00 

Weisbach's  Mechanics    of  Engineering.     Vol.   III.,    Part  I., 

Sec.  II.     (Klein.) 8vo,       5  00 

Weisbach's  Steam  Engines.     (Du  Bois.) 8vo,       5  00 

Wood's  Analytical  ^Mechanics 8vo,       3  00 

"       Elementary  Mechanics 12rao,       125 

"  "  "  Supplement  and  Key 12mo,       1  25 

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Iron— Gold —SiLVEK — Alloys,  Etc. 

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*  "  "  Steel,  Fuel,  etc 8vo, 

Kunhardt's  Ore  Dressing  in  Europe 8vo, 

Metcalf's  Steel — A  Manual  for  Steel  Users 12mo, 

O'DriscoU's  Treatment  of  Gold  Ores 8vo, 

Thurston's  Iron  and  Steel 8vo, 

"  Alloys 8vo, 

Wilson's  Cyanide  Processes 12mo, 

MINERALOGY   AND  MINING. 

Mike  Accidents — Ventilation— Ore  Dressing,  Etc. 

Barringer's  Minerals  of  Commercial  Value Oblong  morocco,  2  50 

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Boyd's  Resources  of  South  Western  Virginia 8vo,  3  00 

"      Map  of  South  Western  Virginia Pocket-book  form,  2  00 

Brush  and  Penfield's  Determinative  Mineralogy.    New  Ed.  8vo,  4  00 

13 


3  00 

7  50 

7  50 

15  00 

15  00 

1  50 

2  00 

2  00 

3  50 

2  50 

1  50 

Chester's  Catalogue  of  Minerals 8vo, 

"  "  "        "         Paper, 

"       Dictionary  of  the  Names  of  Minerals 8vo, 

Dana's  American  Localities  of  Minerals Large  8vo, 

■'•'      Descriptive  Mineralogy   (E.S.)  Large  Svo.  half  morocco, 
"      First  Appendix  to  System  of  Mineralogy.   . .  .Large  8vo, 

"      Mineralogy  and  Petrography.     (J.  D.) 12mo, 

"      Minerals  and  How  to  Study  Them.     (E.  S.) 12mo, 

"      Text-book  of  Mineralogy.     (E.  S.)..  .New  Edition.     8vo, 

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4to,  half  morocco, 

Egleston's  Catalogue  of  Minerals  and  Synonyms 8vo, 

Eissler's  Explosives — Nitroglycerine  and  Dynamite 8yo, 

Hussak's  Rock- forming  Minerals.     (Smith.) Small  8vo, 

Ihlseng's  Manual  of  Mining. . 8vo, 

Kunhardt's  Ore  Dressing  in  Europe 8vo, 

O'Driscoll's  Treatment  of  Gold  Ores Svo, 

*  Penfield's  Record  of  Mineral  Tests Paper,  8vo, 

Rosenbusch's    Microscopical    Physiography  of    Minerals    and 

Rocks.     (Iddiugs.) 8vo, 

Sawyer's  Accidents  in  Mines Large  8vo, 

Stockbridge's  Rocks  and  Soils Svo, 

*Tillman's  Important  Minerals  and  Rocks Svo, 

Walke's  Lectures  on  Explosives Svo, 

"Williams's  Lithology Svo, 

Wilson's  Mine  Ventilation 12mo, 

"         Hydraulic  and  Placer  Mining 12mo, 

STEAM  AND  ELECTRICAL  ENGINES,  BOILERS,  Etc. 

Stationaky—Mauine— Locomotive — Gas  Engines,  Etc. 
{See  also  Engineering,  p.  7.) 

Baldwin's  Steam  Heating  for  Buildings 12mo,  2  50 

Clerk's  Gas  Engine .Small  Svo,  4  00 

Ford's  Boiler  Making  for  Boiler  Makers ISmo,  1  00 

Hemenway's  Indicator  Practice 12mo,  2  00 

Kneass's  Practice  and  Theory  of  the  Injector Svo,  1  50 

MacCord's  Slide  Valve Svo,  2  00 

Meyer's  Modern  Locomotive  Construction 4to,  10  00 

Peabody  and  Miller's  Steam-boilers 8vo,  4  00 

Peabody's  Tables  of  Saturated  Steam Svo,  1  00 

"         Thermodynamics  of  the  Steam  Engine Svo,  5  00 

"         Valve  Gears  for  the  Steam  Engine Svo,  2  50 

"          Manual  of  the  Steam-engine  Indicator 12mo,  1  50 

Pray's  Twenty  Years  with  the  Indicator Large  Svo,  2  50 

Pupin  and  Osterberg's  Thermodynamics 12mo,  1  25 

14 


$1  25 

50 

3  00 

1  00 

12  50 

1  00 

3  00 

1  50 

4  00 

25  00 

2  50 

4  00 

2  00 

4  00 

1  50 

2  00 

50 

5  00 

7  00 

2  50 

2  00 

4-01^ 

3  00 

1  25 

2  50 

Reagan's  Steam  iiud  Electric  Locomotives 12mo,  $2  00 

Riiiitgen's  Thciiiiotl\iiamics.     (Dii  Bois.) 8vo,  5  00 

Sinclair'*  Locomotive  Hunning 12mo,  2  00 

Snow's  Steam-boiler  Practice 8vo.  3  00 

Thurston's  Boiler  Explosions 12mo,  1  50 

"           Engine  and  Boiler  Trials 8vo,  5  00 

^fanual  of  the  Steam  Engine.      Part  I.,   Structure 

auil  Theory 8vo,  6  00 

Manual   of  the    Steam   Engine.      Part  II.,    Design, 

Construction,  and  Operation Svo,  6  00 

2  parts,  10  00 

Thurston's  Philosophy  of  the  Steam  Engine 12mo,  75 

"  Reflection  on  the  Motive  Power  of  Heat.    (Carnot.) 

12ino,  1  50 

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Spangler's  Valve  Gears Svo,  2  50 

Weisbach's  Steam  Engine.     (Du  Bois.) Svo,  5  00 

Whitham's  Steam-engine  Design Svo,  5  00 

Wilson's  Steam  Boilers.     (Flather.) 12mo,  2  50 

"Wood's  Thermodynamics,  Ileat  Motors,  etc Svo,  4  00 

TABLES,  WEIGHTS,   AND  MEASURES. 

Fou  Actuaries,  Chemists,  P:noineers,  Mechanics— Metric 
Tahles,  Etc. 

Adriance's  Laboratory  Calculations 12mo,  1  25 

Allen's  Tables  for  Iron  Analysis Svo,  3  00 

Bixby's  Graphical  Computing  Tables Sheet,  25 

Compton's  Logarithms 12mo,  1  50 

Crandall's  Railway  and  Earthwork  Tables Svo,  1  50 

Egleston's  Weights  and  Measures ISmo,  75 

Fisher's  Table  of  Cubic  Yards Cardboard,  25 

Hudson's  Excavation  Tables.     Vol.11 Svo,  100 

Johnson's  Stadia  and  Earthwork  Tables Svo,  1  25 

Ludlow's  Logarithmic  and  Other  Tables.     (Bass.) 12mo,  2  00 

Totten's  Metrology  ...    Svo,  2  50 

VENTILATION. 

Stea.m  Heating — House  Inspection — Mine  Ventilation. 

Baldwin's  Steam  Heating 12mo,  2  50 

Beard's  Ventilation  of  Mines  12mo,  2  50 

Carpenter's  Heating  and  Ventilating  of  Buildings Svo,  3  00 

Gerhard's  Sanitary  House  Inspection 12mo,  1  00 

Wilson's  Mine  Ventilation.    12mo,  J  25 

15 


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Alcott's  Gems,  Sentimeut,  Language Gilt  edges,  $5  00 

Davis's  Elements  of  Law 8vo,  2  00 

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Ferrel's  Treatise  on  the  Winds 8vo,  4  00 

Haines's  Addresses  Delivered  before  the  Am.  Ry.  Assn.  ..12mo,  2  50 

Mott's  The  Fallacy  of  the  Present  Theory  of  Sound.  .Sq.  lUnio,  1  00 

Richards's  Cost  of  Living 12mo,  1  00 

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Rotherham's    The    Xew    Testament     Critical!}'    Emphasized. 

12mo,  1  50 
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Large  8vo,  2  00 

Totteu's  An  Important  Question  in  Metrology.   8vo,  2  50 

*  Wiley's  Yosemite,  Alaska,  and  Yellowstone 4to,  3  00 

HEBREW  AND  CHALDEE  TEXT=BOOKS. 

For  Schools  and  Theological  Seminaries, 

Gesenius's  Hebrew  and   Chaldee  Lexicon  to  Old   Testament. 

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Green's  Elementary  Hebrew  Grammar 12mo,  1  25 

"       Grammar  of  the  Hebrew  Language  (New  Edition). 8vo,  3  00 

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Letteris's    Hebrew   Bible   (Massoretic  Notes  in   English). 

8vo,  arabesque,  2  25 

MEDICAL. 

Hammarsteu's  Physiological  Chemi.slry.    (Mandel.) 8vo,  4  00 

Mott's  Composition,  Digestibility,  and  Nutritive  Value  of  Food. 

Large  mounted  chart,  1  25 

Ruddiman's  Incompatibilities  in  Prescriptions 8vo,  2  00 

Steel's  Treatise  on  the  Diseases  of  the  Ox 8vo,  6  00 

"      Treatise  on  the  Diseases  of  the  Dog 8vo,  3  50 

WoodhuU's  Military  Hygiene 16mo,  1  50 

Worcester's  Small  Hospitals — Establishment  and  Maintenance, 
including  Atkinson's  Suggestions  for  Hospital  Archi- 
tecture  12mo,  1  26 

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